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1 | ffa6869f | Iustin Pop | Ganeti administrator's guide |
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2 | ffa6869f | Iustin Pop | ============================ |
3 | ffa6869f | Iustin Pop | |
4 | fd07c6b3 | Iustin Pop | Documents Ganeti version |version| |
5 | ffa6869f | Iustin Pop | |
6 | ffa6869f | Iustin Pop | .. contents:: |
7 | ffa6869f | Iustin Pop | |
8 | c71a1a3d | Iustin Pop | .. highlight:: text |
9 | c71a1a3d | Iustin Pop | |
10 | ffa6869f | Iustin Pop | Introduction |
11 | ffa6869f | Iustin Pop | ------------ |
12 | ffa6869f | Iustin Pop | |
13 | c71a1a3d | Iustin Pop | Ganeti is a virtualization cluster management software. You are expected |
14 | c71a1a3d | Iustin Pop | to be a system administrator familiar with your Linux distribution and |
15 | c71a1a3d | Iustin Pop | the Xen or KVM virtualization environments before using it. |
16 | ffa6869f | Iustin Pop | |
17 | ffa6869f | Iustin Pop | The various components of Ganeti all have man pages and interactive |
18 | c71a1a3d | Iustin Pop | help. This manual though will help you getting familiar with the system |
19 | c71a1a3d | Iustin Pop | by explaining the most common operations, grouped by related use. |
20 | ffa6869f | Iustin Pop | |
21 | ffa6869f | Iustin Pop | After a terminology glossary and a section on the prerequisites needed |
22 | c71a1a3d | Iustin Pop | to use this manual, the rest of this document is divided in sections |
23 | c71a1a3d | Iustin Pop | for the different targets that a command affects: instance, nodes, etc. |
24 | ffa6869f | Iustin Pop | |
25 | c71a1a3d | Iustin Pop | .. _terminology-label: |
26 | ffa6869f | Iustin Pop | |
27 | ffa6869f | Iustin Pop | Ganeti terminology |
28 | c71a1a3d | Iustin Pop | ++++++++++++++++++ |
29 | ffa6869f | Iustin Pop | |
30 | c71a1a3d | Iustin Pop | This section provides a small introduction to Ganeti terminology, which |
31 | c71a1a3d | Iustin Pop | might be useful when reading the rest of the document. |
32 | ffa6869f | Iustin Pop | |
33 | ffa6869f | Iustin Pop | Cluster |
34 | c71a1a3d | Iustin Pop | ~~~~~~~ |
35 | ffa6869f | Iustin Pop | |
36 | c71a1a3d | Iustin Pop | A set of machines (nodes) that cooperate to offer a coherent, highly |
37 | c71a1a3d | Iustin Pop | available virtualization service under a single administration domain. |
38 | ffa6869f | Iustin Pop | |
39 | c71a1a3d | Iustin Pop | Node |
40 | c71a1a3d | Iustin Pop | ~~~~ |
41 | c71a1a3d | Iustin Pop | |
42 | c71a1a3d | Iustin Pop | A physical machine which is member of a cluster. Nodes are the basic |
43 | c71a1a3d | Iustin Pop | cluster infrastructure, and they don't need to be fault tolerant in |
44 | c71a1a3d | Iustin Pop | order to achieve high availability for instances. |
45 | c71a1a3d | Iustin Pop | |
46 | c71a1a3d | Iustin Pop | Node can be added and removed (if they host no instances) at will from |
47 | c71a1a3d | Iustin Pop | the cluster. In a HA cluster and only with HA instances, the loss of any |
48 | c71a1a3d | Iustin Pop | single node will not cause disk data loss for any instance; of course, |
49 | c71a1a3d | Iustin Pop | a node crash will cause the crash of the its primary instances. |
50 | c71a1a3d | Iustin Pop | |
51 | c71a1a3d | Iustin Pop | A node belonging to a cluster can be in one of the following roles at a |
52 | c71a1a3d | Iustin Pop | given time: |
53 | c71a1a3d | Iustin Pop | |
54 | c71a1a3d | Iustin Pop | - *master* node, which is the node from which the cluster is controlled |
55 | c71a1a3d | Iustin Pop | - *master candidate* node, only nodes in this role have the full cluster |
56 | c71a1a3d | Iustin Pop | configuration and knowledge, and only master candidates can become the |
57 | c71a1a3d | Iustin Pop | master node |
58 | c71a1a3d | Iustin Pop | - *regular* node, which is the state in which most nodes will be on |
59 | c71a1a3d | Iustin Pop | bigger clusters (>20 nodes) |
60 | c71a1a3d | Iustin Pop | - *drained* node, nodes in this state are functioning normally but the |
61 | c71a1a3d | Iustin Pop | cannot receive new instances; the intention is that nodes in this role |
62 | c71a1a3d | Iustin Pop | have some issue and they are being evacuated for hardware repairs |
63 | c71a1a3d | Iustin Pop | - *offline* node, in which there is a record in the cluster |
64 | c71a1a3d | Iustin Pop | configuration about the node, but the daemons on the master node will |
65 | c71a1a3d | Iustin Pop | not talk to this node; any instances declared as having an offline |
66 | c71a1a3d | Iustin Pop | node as either primary or secondary will be flagged as an error in the |
67 | c71a1a3d | Iustin Pop | cluster verify operation |
68 | c71a1a3d | Iustin Pop | |
69 | c71a1a3d | Iustin Pop | Depending on the role, each node will run a set of daemons: |
70 | c71a1a3d | Iustin Pop | |
71 | c71a1a3d | Iustin Pop | - the :command:`ganeti-noded` daemon, which control the manipulation of |
72 | c71a1a3d | Iustin Pop | this node's hardware resources; it runs on all nodes which are in a |
73 | c71a1a3d | Iustin Pop | cluster |
74 | c71a1a3d | Iustin Pop | - the :command:`ganeti-confd` daemon (Ganeti 2.1+) which runs on all |
75 | c71a1a3d | Iustin Pop | nodes, but is only functional on master candidate nodes |
76 | c71a1a3d | Iustin Pop | - the :command:`ganeti-rapi` daemon which runs on the master node and |
77 | c71a1a3d | Iustin Pop | offers an HTTP-based API for the cluster |
78 | c71a1a3d | Iustin Pop | - the :command:`ganeti-masterd` daemon which runs on the master node and |
79 | c71a1a3d | Iustin Pop | allows control of the cluster |
80 | ffa6869f | Iustin Pop | |
81 | ffa6869f | Iustin Pop | Instance |
82 | c71a1a3d | Iustin Pop | ~~~~~~~~ |
83 | ffa6869f | Iustin Pop | |
84 | c71a1a3d | Iustin Pop | A virtual machine which runs on a cluster. It can be a fault tolerant, |
85 | c71a1a3d | Iustin Pop | highly available entity. |
86 | ffa6869f | Iustin Pop | |
87 | c71a1a3d | Iustin Pop | An instance has various parameters, which are classified in three |
88 | c71a1a3d | Iustin Pop | categories: hypervisor related-parameters (called ``hvparams``), general |
89 | c71a1a3d | Iustin Pop | parameters (called ``beparams``) and per network-card parameters (called |
90 | c71a1a3d | Iustin Pop | ``nicparams``). All these parameters can be modified either at instance |
91 | c71a1a3d | Iustin Pop | level or via defaults at cluster level. |
92 | ffa6869f | Iustin Pop | |
93 | c71a1a3d | Iustin Pop | Disk template |
94 | ffa6869f | Iustin Pop | ~~~~~~~~~~~~~ |
95 | ffa6869f | Iustin Pop | |
96 | c71a1a3d | Iustin Pop | The are multiple options for the storage provided to an instance; while |
97 | c71a1a3d | Iustin Pop | the instance sees the same virtual drive in all cases, the node-level |
98 | c71a1a3d | Iustin Pop | configuration varies between them. |
99 | ffa6869f | Iustin Pop | |
100 | c71a1a3d | Iustin Pop | There are four disk templates you can choose from: |
101 | ffa6869f | Iustin Pop | |
102 | c71a1a3d | Iustin Pop | diskless |
103 | c71a1a3d | Iustin Pop | The instance has no disks. Only used for special purpose operating |
104 | c71a1a3d | Iustin Pop | systems or for testing. |
105 | c71a1a3d | Iustin Pop | |
106 | c71a1a3d | Iustin Pop | file |
107 | c71a1a3d | Iustin Pop | The instance will use plain files as backend for its disks. No |
108 | c71a1a3d | Iustin Pop | redundancy is provided, and this is somewhat more difficult to |
109 | c71a1a3d | Iustin Pop | configure for high performance. |
110 | c71a1a3d | Iustin Pop | |
111 | c71a1a3d | Iustin Pop | plain |
112 | c71a1a3d | Iustin Pop | The instance will use LVM devices as backend for its disks. No |
113 | c71a1a3d | Iustin Pop | redundancy is provided. |
114 | c71a1a3d | Iustin Pop | |
115 | c71a1a3d | Iustin Pop | drbd |
116 | c71a1a3d | Iustin Pop | .. note:: This is only valid for multi-node clusters using DRBD 8.0+ |
117 | c71a1a3d | Iustin Pop | |
118 | c71a1a3d | Iustin Pop | A mirror is set between the local node and a remote one, which must be |
119 | c71a1a3d | Iustin Pop | specified with the second value of the --node option. Use this option |
120 | c71a1a3d | Iustin Pop | to obtain a highly available instance that can be failed over to a |
121 | c71a1a3d | Iustin Pop | remote node should the primary one fail. |
122 | c71a1a3d | Iustin Pop | |
123 | c71a1a3d | Iustin Pop | IAllocator |
124 | c71a1a3d | Iustin Pop | ~~~~~~~~~~ |
125 | c71a1a3d | Iustin Pop | |
126 | c71a1a3d | Iustin Pop | A framework for using external (user-provided) scripts to compute the |
127 | c71a1a3d | Iustin Pop | placement of instances on the cluster nodes. This eliminates the need to |
128 | c71a1a3d | Iustin Pop | manually specify nodes in instance add, instance moves, node evacuate, |
129 | c71a1a3d | Iustin Pop | etc. |
130 | c71a1a3d | Iustin Pop | |
131 | c71a1a3d | Iustin Pop | In order for Ganeti to be able to use these scripts, they must be place |
132 | c71a1a3d | Iustin Pop | in the iallocator directory (usually ``lib/ganeti/iallocators`` under |
133 | c71a1a3d | Iustin Pop | the installation prefix, e.g. ``/usr/local``). |
134 | c71a1a3d | Iustin Pop | |
135 | c71a1a3d | Iustin Pop | “Primary” and “secondary” concepts |
136 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
137 | c71a1a3d | Iustin Pop | |
138 | c71a1a3d | Iustin Pop | An instance has a primary and depending on the disk configuration, might |
139 | c71a1a3d | Iustin Pop | also have a secondary node. The instance always runs on the primary node |
140 | c71a1a3d | Iustin Pop | and only uses its secondary node for disk replication. |
141 | c71a1a3d | Iustin Pop | |
142 | c71a1a3d | Iustin Pop | Similarly, the term of primary and secondary instances when talking |
143 | c71a1a3d | Iustin Pop | about a node refers to the set of instances having the given node as |
144 | c71a1a3d | Iustin Pop | primary, respectively secondary. |
145 | c71a1a3d | Iustin Pop | |
146 | c71a1a3d | Iustin Pop | Tags |
147 | c71a1a3d | Iustin Pop | ~~~~ |
148 | c71a1a3d | Iustin Pop | |
149 | c71a1a3d | Iustin Pop | Tags are short strings that can be attached to either to cluster itself, |
150 | c71a1a3d | Iustin Pop | or to nodes or instances. They are useful as a very simplistic |
151 | c71a1a3d | Iustin Pop | information store for helping with cluster administration, for example |
152 | c71a1a3d | Iustin Pop | by attaching owner information to each instance after it's created:: |
153 | ffa6869f | Iustin Pop | |
154 | c71a1a3d | Iustin Pop | gnt-instance add … instance1 |
155 | c71a1a3d | Iustin Pop | gnt-instance add-tags instance1 owner:user2 |
156 | c71a1a3d | Iustin Pop | |
157 | c71a1a3d | Iustin Pop | And then by listing each instance and its tags, this information could |
158 | c71a1a3d | Iustin Pop | be used for contacting the users of each instance. |
159 | c71a1a3d | Iustin Pop | |
160 | c71a1a3d | Iustin Pop | Jobs and OpCodes |
161 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~ |
162 | c71a1a3d | Iustin Pop | |
163 | c71a1a3d | Iustin Pop | While not directly visible by an end-user, it's useful to know that a |
164 | c71a1a3d | Iustin Pop | basic cluster operation (e.g. starting an instance) is represented |
165 | c71a1a3d | Iustin Pop | internall by Ganeti as an *OpCode* (abbreviation from operation |
166 | c71a1a3d | Iustin Pop | code). These OpCodes are executed as part of a *Job*. The OpCodes in a |
167 | c71a1a3d | Iustin Pop | single Job are processed serially by Ganeti, but different Jobs will be |
168 | c71a1a3d | Iustin Pop | processed (depending on resource availability) in parallel. |
169 | c71a1a3d | Iustin Pop | |
170 | c71a1a3d | Iustin Pop | For example, shutting down the entire cluster can be done by running the |
171 | c71a1a3d | Iustin Pop | command ``gnt-instance shutdown --all``, which will submit for each |
172 | c71a1a3d | Iustin Pop | instance a separate job containing the “shutdown instance” OpCode. |
173 | c71a1a3d | Iustin Pop | |
174 | c71a1a3d | Iustin Pop | |
175 | c71a1a3d | Iustin Pop | Prerequisites |
176 | c71a1a3d | Iustin Pop | +++++++++++++ |
177 | c71a1a3d | Iustin Pop | |
178 | c71a1a3d | Iustin Pop | You need to have your Ganeti cluster installed and configured before you |
179 | c71a1a3d | Iustin Pop | try any of the commands in this document. Please follow the |
180 | c71a1a3d | Iustin Pop | :doc:`install` for instructions on how to do that. |
181 | c71a1a3d | Iustin Pop | |
182 | c71a1a3d | Iustin Pop | Instance management |
183 | c71a1a3d | Iustin Pop | ------------------- |
184 | c71a1a3d | Iustin Pop | |
185 | c71a1a3d | Iustin Pop | Adding an instance |
186 | c71a1a3d | Iustin Pop | ++++++++++++++++++ |
187 | c71a1a3d | Iustin Pop | |
188 | c71a1a3d | Iustin Pop | The add operation might seem complex due to the many parameters it |
189 | c71a1a3d | Iustin Pop | accepts, but once you have understood the (few) required parameters and |
190 | c71a1a3d | Iustin Pop | the customisation capabilities you will see it is an easy operation. |
191 | c71a1a3d | Iustin Pop | |
192 | c71a1a3d | Iustin Pop | The add operation requires at minimum five parameters: |
193 | c71a1a3d | Iustin Pop | |
194 | c71a1a3d | Iustin Pop | - the OS for the instance |
195 | c71a1a3d | Iustin Pop | - the disk template |
196 | c71a1a3d | Iustin Pop | - the disk count and size |
197 | c71a1a3d | Iustin Pop | - the node specification or alternatively the iallocator to use |
198 | c71a1a3d | Iustin Pop | - and finally the instance name |
199 | c71a1a3d | Iustin Pop | |
200 | c71a1a3d | Iustin Pop | The OS for the instance must be visible in the output of the command |
201 | c71a1a3d | Iustin Pop | ``gnt-os list`` and specifies which guest OS to install on the instance. |
202 | c71a1a3d | Iustin Pop | |
203 | c71a1a3d | Iustin Pop | The disk template specifies what kind of storage to use as backend for |
204 | c71a1a3d | Iustin Pop | the (virtual) disks presented to the instance; note that for instances |
205 | c71a1a3d | Iustin Pop | with multiple virtual disks, they all must be of the same type. |
206 | c71a1a3d | Iustin Pop | |
207 | c71a1a3d | Iustin Pop | The node(s) on which the instance will run can be given either manually, |
208 | c71a1a3d | Iustin Pop | via the ``-n`` option, or computed automatically by Ganeti, if you have |
209 | c71a1a3d | Iustin Pop | installed any iallocator script. |
210 | c71a1a3d | Iustin Pop | |
211 | c71a1a3d | Iustin Pop | With the above parameters in mind, the command is:: |
212 | ffa6869f | Iustin Pop | |
213 | ffa6869f | Iustin Pop | gnt-instance add \ |
214 | c71a1a3d | Iustin Pop | -n TARGET_NODE:SECONDARY_NODE \ |
215 | c71a1a3d | Iustin Pop | -o OS_TYPE \ |
216 | c71a1a3d | Iustin Pop | -t DISK_TEMPLATE -s DISK_SIZE \ |
217 | ffa6869f | Iustin Pop | INSTANCE_NAME |
218 | ffa6869f | Iustin Pop | |
219 | ffa6869f | Iustin Pop | The instance name must be resolvable (e.g. exist in DNS) and usually |
220 | c71a1a3d | Iustin Pop | points to an address in the same subnet as the cluster itself. |
221 | ffa6869f | Iustin Pop | |
222 | c71a1a3d | Iustin Pop | The above command has the minimum required options; other options you |
223 | c71a1a3d | Iustin Pop | can give include, among others: |
224 | ffa6869f | Iustin Pop | |
225 | ffa6869f | Iustin Pop | - The memory size (``-B memory``) |
226 | ffa6869f | Iustin Pop | |
227 | ffa6869f | Iustin Pop | - The number of virtual CPUs (``-B vcpus``) |
228 | ffa6869f | Iustin Pop | |
229 | ffa6869f | Iustin Pop | - Arguments for the NICs of the instance; by default, a single-NIC |
230 | ffa6869f | Iustin Pop | instance is created. The IP and/or bridge of the NIC can be changed |
231 | ffa6869f | Iustin Pop | via ``--nic 0:ip=IP,bridge=BRIDGE`` |
232 | ffa6869f | Iustin Pop | |
233 | c71a1a3d | Iustin Pop | See the manpage for gnt-instance for the detailed option list. |
234 | ffa6869f | Iustin Pop | |
235 | c71a1a3d | Iustin Pop | For example if you want to create an highly available instance, with a |
236 | c71a1a3d | Iustin Pop | single disk of 50GB and the default memory size, having primary node |
237 | c71a1a3d | Iustin Pop | ``node1`` and secondary node ``node3``, use the following command:: |
238 | ffa6869f | Iustin Pop | |
239 | c71a1a3d | Iustin Pop | gnt-instance add -n node1:node3 -o debootstrap -t drbd \ |
240 | c71a1a3d | Iustin Pop | instance1 |
241 | ffa6869f | Iustin Pop | |
242 | c71a1a3d | Iustin Pop | There is a also a command for batch instance creation from a |
243 | c71a1a3d | Iustin Pop | specification file, see the ``batch-create`` operation in the |
244 | c71a1a3d | Iustin Pop | gnt-instance manual page. |
245 | ffa6869f | Iustin Pop | |
246 | c71a1a3d | Iustin Pop | Regular instance operations |
247 | c71a1a3d | Iustin Pop | +++++++++++++++++++++++++++ |
248 | ffa6869f | Iustin Pop | |
249 | c71a1a3d | Iustin Pop | Removal |
250 | c71a1a3d | Iustin Pop | ~~~~~~~ |
251 | ffa6869f | Iustin Pop | |
252 | c71a1a3d | Iustin Pop | Removing an instance is even easier than creating one. This operation is |
253 | c71a1a3d | Iustin Pop | irreversible and destroys all the contents of your instance. Use with |
254 | c71a1a3d | Iustin Pop | care:: |
255 | ffa6869f | Iustin Pop | |
256 | ffa6869f | Iustin Pop | gnt-instance remove INSTANCE_NAME |
257 | ffa6869f | Iustin Pop | |
258 | c71a1a3d | Iustin Pop | Startup/shutdown |
259 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~ |
260 | ffa6869f | Iustin Pop | |
261 | ffa6869f | Iustin Pop | Instances are automatically started at instance creation time. To |
262 | ffa6869f | Iustin Pop | manually start one which is currently stopped you can run:: |
263 | ffa6869f | Iustin Pop | |
264 | ffa6869f | Iustin Pop | gnt-instance startup INSTANCE_NAME |
265 | ffa6869f | Iustin Pop | |
266 | ffa6869f | Iustin Pop | While the command to stop one is:: |
267 | ffa6869f | Iustin Pop | |
268 | ffa6869f | Iustin Pop | gnt-instance shutdown INSTANCE_NAME |
269 | ffa6869f | Iustin Pop | |
270 | c71a1a3d | Iustin Pop | .. warning:: Do not use the Xen or KVM commands directly to stop |
271 | c71a1a3d | Iustin Pop | instances. If you run for example ``xm shutdown`` or ``xm destroy`` |
272 | c71a1a3d | Iustin Pop | on an instance Ganeti will automatically restart it (via the |
273 | c71a1a3d | Iustin Pop | :command:`ganeti-watcher` command which is launched via cron). |
274 | c71a1a3d | Iustin Pop | |
275 | c71a1a3d | Iustin Pop | Querying instances |
276 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~ |
277 | c71a1a3d | Iustin Pop | |
278 | c71a1a3d | Iustin Pop | There are two ways to get information about instances: listing |
279 | c71a1a3d | Iustin Pop | instances, which does a tabular output containing a given set of fields |
280 | c71a1a3d | Iustin Pop | about each instance, and querying detailed information about a set of |
281 | c71a1a3d | Iustin Pop | instances. |
282 | c71a1a3d | Iustin Pop | |
283 | ffa6869f | Iustin Pop | The command to see all the instances configured and their status is:: |
284 | ffa6869f | Iustin Pop | |
285 | ffa6869f | Iustin Pop | gnt-instance list |
286 | ffa6869f | Iustin Pop | |
287 | c71a1a3d | Iustin Pop | The command can return a custom set of information when using the ``-o`` |
288 | c71a1a3d | Iustin Pop | option (as always, check the manpage for a detailed specification). Each |
289 | c71a1a3d | Iustin Pop | instance will be represented on a line, thus making it easy to parse |
290 | c71a1a3d | Iustin Pop | this output via the usual shell utilities (grep, sed, etc.). |
291 | c71a1a3d | Iustin Pop | |
292 | c71a1a3d | Iustin Pop | To get more detailed information about an instance, you can run:: |
293 | c71a1a3d | Iustin Pop | |
294 | c71a1a3d | Iustin Pop | gnt-instance info INSTANCE |
295 | c71a1a3d | Iustin Pop | |
296 | c71a1a3d | Iustin Pop | which will give a multi-line block of information about the instance, |
297 | c71a1a3d | Iustin Pop | it's hardware resources (especially its disks and their redundancy |
298 | c71a1a3d | Iustin Pop | status), etc. This is harder to parse and is more expensive than the |
299 | c71a1a3d | Iustin Pop | list operation, but returns much more detailed information. |
300 | ffa6869f | Iustin Pop | |
301 | ffa6869f | Iustin Pop | |
302 | c71a1a3d | Iustin Pop | Export/Import |
303 | c71a1a3d | Iustin Pop | +++++++++++++ |
304 | c71a1a3d | Iustin Pop | |
305 | c71a1a3d | Iustin Pop | You can create a snapshot of an instance disk and its Ganeti |
306 | ffa6869f | Iustin Pop | configuration, which then you can backup, or import into another |
307 | ffa6869f | Iustin Pop | cluster. The way to export an instance is:: |
308 | ffa6869f | Iustin Pop | |
309 | ffa6869f | Iustin Pop | gnt-backup export -n TARGET_NODE INSTANCE_NAME |
310 | ffa6869f | Iustin Pop | |
311 | c71a1a3d | Iustin Pop | |
312 | ffa6869f | Iustin Pop | The target node can be any node in the cluster with enough space under |
313 | c71a1a3d | Iustin Pop | ``/srv/ganeti`` to hold the instance image. Use the ``--noshutdown`` |
314 | c71a1a3d | Iustin Pop | option to snapshot an instance without rebooting it. Note that Ganeti |
315 | c71a1a3d | Iustin Pop | only keeps one snapshot for an instance - any previous snapshot of the |
316 | c71a1a3d | Iustin Pop | same instance existing cluster-wide under ``/srv/ganeti`` will be |
317 | c71a1a3d | Iustin Pop | removed by this operation: if you want to keep them, you need to move |
318 | c71a1a3d | Iustin Pop | them out of the Ganeti exports directory. |
319 | ffa6869f | Iustin Pop | |
320 | c71a1a3d | Iustin Pop | Importing an instance is similar to creating a new one, but additionally |
321 | c71a1a3d | Iustin Pop | one must specify the location of the snapshot. The command is:: |
322 | ffa6869f | Iustin Pop | |
323 | 33ea43b6 | Iustin Pop | gnt-backup import -n TARGET_NODE \ |
324 | ffa6869f | Iustin Pop | --src-node=NODE --src-dir=DIR INSTANCE_NAME |
325 | ffa6869f | Iustin Pop | |
326 | 33ea43b6 | Iustin Pop | By default, parameters will be read from the export information, but you |
327 | 33ea43b6 | Iustin Pop | can of course pass them in via the command line - most of the options |
328 | 33ea43b6 | Iustin Pop | available for the command :command:`gnt-instance add` are supported here |
329 | 33ea43b6 | Iustin Pop | too. |
330 | ffa6869f | Iustin Pop | |
331 | 17227cd1 | Iustin Pop | Import of foreign instances |
332 | 17227cd1 | Iustin Pop | +++++++++++++++++++++++++++ |
333 | 17227cd1 | Iustin Pop | |
334 | 17227cd1 | Iustin Pop | There is a possibility to import a foreign instance whose disk data is |
335 | 17227cd1 | Iustin Pop | already stored as LVM volumes without going through copying it: the disk |
336 | 17227cd1 | Iustin Pop | adoption mode. |
337 | 17227cd1 | Iustin Pop | |
338 | 17227cd1 | Iustin Pop | For this, ensure that the original, non-managed instance is stopped, |
339 | 17227cd1 | Iustin Pop | then create a Ganeti instance in the usual way, except that instead of |
340 | 17227cd1 | Iustin Pop | passing the disk information you specify the current volumes:: |
341 | 17227cd1 | Iustin Pop | |
342 | 17227cd1 | Iustin Pop | gnt-instance add -t plain -n HOME_NODE ... \ |
343 | 17227cd1 | Iustin Pop | --disk 0:adopt=lv_name INSTANCE_NAME |
344 | 17227cd1 | Iustin Pop | |
345 | 17227cd1 | Iustin Pop | This will take over the given logical volumes, rename them to the Ganeti |
346 | 17227cd1 | Iustin Pop | standard (UUID-based), and without installing the OS on them start |
347 | 17227cd1 | Iustin Pop | directly the instance. If you configure the hypervisor similar to the |
348 | 17227cd1 | Iustin Pop | non-managed configuration that the instance had, the transition should |
349 | 17227cd1 | Iustin Pop | be seamless for the instance. For more than one disk, just pass another |
350 | 17227cd1 | Iustin Pop | disk parameter (e.g. ``--disk 1:adopt=...``). |
351 | 17227cd1 | Iustin Pop | |
352 | c71a1a3d | Iustin Pop | Instance HA features |
353 | c71a1a3d | Iustin Pop | -------------------- |
354 | ffa6869f | Iustin Pop | |
355 | ffa6869f | Iustin Pop | .. note:: This section only applies to multi-node clusters |
356 | ffa6869f | Iustin Pop | |
357 | c71a1a3d | Iustin Pop | .. _instance-change-primary-label: |
358 | c71a1a3d | Iustin Pop | |
359 | c71a1a3d | Iustin Pop | Changing the primary node |
360 | c71a1a3d | Iustin Pop | +++++++++++++++++++++++++ |
361 | c71a1a3d | Iustin Pop | |
362 | c71a1a3d | Iustin Pop | There are three ways to exchange an instance's primary and secondary |
363 | c71a1a3d | Iustin Pop | nodes; the right one to choose depends on how the instance has been |
364 | c71a1a3d | Iustin Pop | created and the status of its current primary node. See |
365 | c71a1a3d | Iustin Pop | :ref:`rest-redundancy-label` for information on changing the secondary |
366 | c71a1a3d | Iustin Pop | node. Note that it's only possible to change the primary node to the |
367 | c71a1a3d | Iustin Pop | secondary and vice-versa; a direct change of the primary node with a |
368 | c71a1a3d | Iustin Pop | third node, while keeping the current secondary is not possible in a |
369 | c71a1a3d | Iustin Pop | single step, only via multiple operations as detailed in |
370 | c71a1a3d | Iustin Pop | :ref:`instance-relocation-label`. |
371 | c71a1a3d | Iustin Pop | |
372 | ffa6869f | Iustin Pop | Failing over an instance |
373 | ffa6869f | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~ |
374 | ffa6869f | Iustin Pop | |
375 | ffa6869f | Iustin Pop | If an instance is built in highly available mode you can at any time |
376 | ffa6869f | Iustin Pop | fail it over to its secondary node, even if the primary has somehow |
377 | ffa6869f | Iustin Pop | failed and it's not up anymore. Doing it is really easy, on the master |
378 | ffa6869f | Iustin Pop | node you can just run:: |
379 | ffa6869f | Iustin Pop | |
380 | ffa6869f | Iustin Pop | gnt-instance failover INSTANCE_NAME |
381 | ffa6869f | Iustin Pop | |
382 | ffa6869f | Iustin Pop | That's it. After the command completes the secondary node is now the |
383 | c71a1a3d | Iustin Pop | primary, and vice-versa. |
384 | ffa6869f | Iustin Pop | |
385 | ffa6869f | Iustin Pop | Live migrating an instance |
386 | ffa6869f | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~ |
387 | ffa6869f | Iustin Pop | |
388 | c71a1a3d | Iustin Pop | If an instance is built in highly available mode, it currently runs and |
389 | c71a1a3d | Iustin Pop | both its nodes are running fine, you can at migrate it over to its |
390 | c71a1a3d | Iustin Pop | secondary node, without downtime. On the master node you need to run:: |
391 | ffa6869f | Iustin Pop | |
392 | ffa6869f | Iustin Pop | gnt-instance migrate INSTANCE_NAME |
393 | ffa6869f | Iustin Pop | |
394 | c71a1a3d | Iustin Pop | The current load on the instance and its memory size will influence how |
395 | c71a1a3d | Iustin Pop | long the migration will take. In any case, for both KVM and Xen |
396 | c71a1a3d | Iustin Pop | hypervisors, the migration will be transparent to the instance. |
397 | ffa6869f | Iustin Pop | |
398 | c71a1a3d | Iustin Pop | Moving an instance (offline) |
399 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
400 | ffa6869f | Iustin Pop | |
401 | c71a1a3d | Iustin Pop | If an instance has not been create as mirrored, then the only way to |
402 | c71a1a3d | Iustin Pop | change its primary node is to execute the move command:: |
403 | ffa6869f | Iustin Pop | |
404 | c71a1a3d | Iustin Pop | gnt-instance move -n NEW_NODE INSTANCE |
405 | ffa6869f | Iustin Pop | |
406 | c71a1a3d | Iustin Pop | This has a few prerequisites: |
407 | ffa6869f | Iustin Pop | |
408 | c71a1a3d | Iustin Pop | - the instance must be stopped |
409 | c71a1a3d | Iustin Pop | - its current primary node must be on-line and healthy |
410 | c71a1a3d | Iustin Pop | - the disks of the instance must not have any errors |
411 | ffa6869f | Iustin Pop | |
412 | c71a1a3d | Iustin Pop | Since this operation actually copies the data from the old node to the |
413 | c71a1a3d | Iustin Pop | new node, expect it to take proportional to the size of the instance's |
414 | c71a1a3d | Iustin Pop | disks and the speed of both the nodes' I/O system and their networking. |
415 | ffa6869f | Iustin Pop | |
416 | c71a1a3d | Iustin Pop | Disk operations |
417 | c71a1a3d | Iustin Pop | +++++++++++++++ |
418 | ffa6869f | Iustin Pop | |
419 | c71a1a3d | Iustin Pop | Disk failures are a common cause of errors in any server |
420 | c71a1a3d | Iustin Pop | deployment. Ganeti offers protection from single-node failure if your |
421 | c71a1a3d | Iustin Pop | instances were created in HA mode, and it also offers ways to restore |
422 | c71a1a3d | Iustin Pop | redundancy after a failure. |
423 | ffa6869f | Iustin Pop | |
424 | c71a1a3d | Iustin Pop | Preparing for disk operations |
425 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
426 | ffa6869f | Iustin Pop | |
427 | c71a1a3d | Iustin Pop | It is important to note that for Ganeti to be able to do any disk |
428 | c71a1a3d | Iustin Pop | operation, the Linux machines on top of which Ganeti must be consistent; |
429 | c71a1a3d | Iustin Pop | for LVM, this means that the LVM commands must not return failures; it |
430 | c71a1a3d | Iustin Pop | is common that after a complete disk failure, any LVM command aborts |
431 | c71a1a3d | Iustin Pop | with an error similar to:: |
432 | ffa6869f | Iustin Pop | |
433 | c71a1a3d | Iustin Pop | # vgs |
434 | c71a1a3d | Iustin Pop | /dev/sdb1: read failed after 0 of 4096 at 0: Input/output error |
435 | c71a1a3d | Iustin Pop | /dev/sdb1: read failed after 0 of 4096 at 750153695232: Input/output |
436 | c71a1a3d | Iustin Pop | error |
437 | c71a1a3d | Iustin Pop | /dev/sdb1: read failed after 0 of 4096 at 0: Input/output error |
438 | c71a1a3d | Iustin Pop | Couldn't find device with uuid |
439 | c71a1a3d | Iustin Pop | 't30jmN-4Rcf-Fr5e-CURS-pawt-z0jU-m1TgeJ'. |
440 | c71a1a3d | Iustin Pop | Couldn't find all physical volumes for volume group xenvg. |
441 | ffa6869f | Iustin Pop | |
442 | c71a1a3d | Iustin Pop | Before restoring an instance's disks to healthy status, it's needed to |
443 | c71a1a3d | Iustin Pop | fix the volume group used by Ganeti so that we can actually create and |
444 | c71a1a3d | Iustin Pop | manage the logical volumes. This is usually done in a multi-step |
445 | c71a1a3d | Iustin Pop | process: |
446 | ffa6869f | Iustin Pop | |
447 | c71a1a3d | Iustin Pop | #. first, if the disk is completely gone and LVM commands exit with |
448 | c71a1a3d | Iustin Pop | “Couldn't find device with uuid…” then you need to run the command:: |
449 | c71a1a3d | Iustin Pop | |
450 | c71a1a3d | Iustin Pop | vgreduce --removemissing VOLUME_GROUP |
451 | c71a1a3d | Iustin Pop | |
452 | c71a1a3d | Iustin Pop | #. after the above command, the LVM commands should be executing |
453 | c71a1a3d | Iustin Pop | normally (warnings are normal, but the commands will not fail |
454 | c71a1a3d | Iustin Pop | completely). |
455 | c71a1a3d | Iustin Pop | |
456 | c71a1a3d | Iustin Pop | #. if the failed disk is still visible in the output of the ``pvs`` |
457 | c71a1a3d | Iustin Pop | command, you need to deactivate it from allocations by running:: |
458 | c71a1a3d | Iustin Pop | |
459 | c71a1a3d | Iustin Pop | pvs -x n /dev/DISK |
460 | ffa6869f | Iustin Pop | |
461 | c71a1a3d | Iustin Pop | At this point, the volume group should be consistent and any bad |
462 | c71a1a3d | Iustin Pop | physical volumes should not longer be available for allocation. |
463 | c71a1a3d | Iustin Pop | |
464 | c71a1a3d | Iustin Pop | Note that since version 2.1 Ganeti provides some commands to automate |
465 | c71a1a3d | Iustin Pop | these two operations, see :ref:`storage-units-label`. |
466 | c71a1a3d | Iustin Pop | |
467 | c71a1a3d | Iustin Pop | .. _rest-redundancy-label: |
468 | c71a1a3d | Iustin Pop | |
469 | c71a1a3d | Iustin Pop | Restoring redundancy for DRBD-based instances |
470 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
471 | c71a1a3d | Iustin Pop | |
472 | c71a1a3d | Iustin Pop | A DRBD instance has two nodes, and the storage on one of them has |
473 | c71a1a3d | Iustin Pop | failed. Depending on which node (primary or secondary) has failed, you |
474 | c71a1a3d | Iustin Pop | have three options at hand: |
475 | c71a1a3d | Iustin Pop | |
476 | c71a1a3d | Iustin Pop | - if the storage on the primary node has failed, you need to re-create |
477 | c71a1a3d | Iustin Pop | the disks on it |
478 | c71a1a3d | Iustin Pop | - if the storage on the secondary node has failed, you can either |
479 | c71a1a3d | Iustin Pop | re-create the disks on it or change the secondary and recreate |
480 | c71a1a3d | Iustin Pop | redundancy on the new secondary node |
481 | c71a1a3d | Iustin Pop | |
482 | c71a1a3d | Iustin Pop | Of course, at any point it's possible to force re-creation of disks even |
483 | c71a1a3d | Iustin Pop | though everything is already fine. |
484 | c71a1a3d | Iustin Pop | |
485 | c71a1a3d | Iustin Pop | For all three cases, the ``replace-disks`` operation can be used:: |
486 | c71a1a3d | Iustin Pop | |
487 | c71a1a3d | Iustin Pop | # re-create disks on the primary node |
488 | c71a1a3d | Iustin Pop | gnt-instance replace-disks -p INSTANCE_NAME |
489 | c71a1a3d | Iustin Pop | # re-create disks on the current secondary |
490 | c71a1a3d | Iustin Pop | gnt-instance replace-disks -s INSTANCE_NAME |
491 | c71a1a3d | Iustin Pop | # change the secondary node, via manual specification |
492 | c71a1a3d | Iustin Pop | gnt-instance replace-disks -n NODE INSTANCE_NAME |
493 | c71a1a3d | Iustin Pop | # change the secondary node, via an iallocator script |
494 | c71a1a3d | Iustin Pop | gnt-instance replace-disks -I SCRIPT INSTANCE_NAME |
495 | c71a1a3d | Iustin Pop | # since Ganeti 2.1: automatically fix the primary or secondary node |
496 | c71a1a3d | Iustin Pop | gnt-instance replace-disks -a INSTANCE_NAME |
497 | c71a1a3d | Iustin Pop | |
498 | c71a1a3d | Iustin Pop | Since the process involves copying all data from the working node to the |
499 | c71a1a3d | Iustin Pop | target node, it will take a while, depending on the instance's disk |
500 | c71a1a3d | Iustin Pop | size, node I/O system and network speed. But it is (baring any network |
501 | c71a1a3d | Iustin Pop | interruption) completely transparent for the instance. |
502 | c71a1a3d | Iustin Pop | |
503 | c71a1a3d | Iustin Pop | Re-creating disks for non-redundant instances |
504 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
505 | c71a1a3d | Iustin Pop | |
506 | c71a1a3d | Iustin Pop | .. versionadded:: 2.1 |
507 | c71a1a3d | Iustin Pop | |
508 | c71a1a3d | Iustin Pop | For non-redundant instances, there isn't a copy (except backups) to |
509 | c71a1a3d | Iustin Pop | re-create the disks. But it's possible to at-least re-create empty |
510 | c71a1a3d | Iustin Pop | disks, after which a reinstall can be run, via the ``recreate-disks`` |
511 | c71a1a3d | Iustin Pop | command:: |
512 | c71a1a3d | Iustin Pop | |
513 | c71a1a3d | Iustin Pop | gnt-instance recreate-disks INSTANCE |
514 | c71a1a3d | Iustin Pop | |
515 | c71a1a3d | Iustin Pop | Note that this will fail if the disks already exists. |
516 | c71a1a3d | Iustin Pop | |
517 | bbf74a76 | Iustin Pop | Conversion of an instance's disk type |
518 | bbf74a76 | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
519 | bbf74a76 | Iustin Pop | |
520 | bbf74a76 | Iustin Pop | It is possible to convert between a non-redundant instance of type |
521 | bbf74a76 | Iustin Pop | ``plain`` (LVM storage) and redundant ``drbd`` via the ``gnt-instance |
522 | bbf74a76 | Iustin Pop | modify`` command:: |
523 | bbf74a76 | Iustin Pop | |
524 | bbf74a76 | Iustin Pop | # start with a non-redundant instance |
525 | bbf74a76 | Iustin Pop | gnt-instance add -t plain ... INSTANCE |
526 | bbf74a76 | Iustin Pop | |
527 | bbf74a76 | Iustin Pop | # later convert it to redundant |
528 | bbf74a76 | Iustin Pop | gnt-instance stop INSTANCE |
529 | bbf74a76 | Iustin Pop | gnt-instance modify -t drbd INSTANCE |
530 | bbf74a76 | Iustin Pop | gnt-instance start INSTANCE |
531 | bbf74a76 | Iustin Pop | |
532 | bbf74a76 | Iustin Pop | # and convert it back |
533 | bbf74a76 | Iustin Pop | gnt-instance stop INSTANCE |
534 | bbf74a76 | Iustin Pop | gnt-instance modify -t plain INSTANCE |
535 | bbf74a76 | Iustin Pop | gnt-instance start INSTANCE |
536 | bbf74a76 | Iustin Pop | |
537 | bbf74a76 | Iustin Pop | The conversion must be done while the instance is stopped, and |
538 | bbf74a76 | Iustin Pop | converting from plain to drbd template presents a small risk, especially |
539 | bbf74a76 | Iustin Pop | if the instance has multiple disks and/or if one node fails during the |
540 | bbf74a76 | Iustin Pop | conversion procedure). As such, it's recommended (as always) to make |
541 | bbf74a76 | Iustin Pop | sure that downtime for manual recovery is acceptable and that the |
542 | bbf74a76 | Iustin Pop | instance has up-to-date backups. |
543 | bbf74a76 | Iustin Pop | |
544 | c71a1a3d | Iustin Pop | Debugging instances |
545 | c71a1a3d | Iustin Pop | +++++++++++++++++++ |
546 | ffa6869f | Iustin Pop | |
547 | ffa6869f | Iustin Pop | Accessing an instance's disks |
548 | ffa6869f | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
549 | ffa6869f | Iustin Pop | |
550 | c71a1a3d | Iustin Pop | From an instance's primary node you can have access to its disks. Never |
551 | ffa6869f | Iustin Pop | ever mount the underlying logical volume manually on a fault tolerant |
552 | c71a1a3d | Iustin Pop | instance, or will break replication and your data will be |
553 | c71a1a3d | Iustin Pop | inconsistent. The correct way to access an instance's disks is to run |
554 | c71a1a3d | Iustin Pop | (on the master node, as usual) the command:: |
555 | c71a1a3d | Iustin Pop | |
556 | c71a1a3d | Iustin Pop | gnt-instance activate-disks INSTANCE |
557 | c71a1a3d | Iustin Pop | |
558 | c71a1a3d | Iustin Pop | And then, *on the primary node of the instance*, access the device that |
559 | c71a1a3d | Iustin Pop | gets created. For example, you could mount the given disks, then edit |
560 | c71a1a3d | Iustin Pop | files on the filesystem, etc. |
561 | c71a1a3d | Iustin Pop | |
562 | c71a1a3d | Iustin Pop | Note that with partitioned disks (as opposed to whole-disk filesystems), |
563 | c71a1a3d | Iustin Pop | you will need to use a tool like :manpage:`kpartx(8)`:: |
564 | ffa6869f | Iustin Pop | |
565 | c71a1a3d | Iustin Pop | node1# gnt-instance activate-disks instance1 |
566 | c71a1a3d | Iustin Pop | … |
567 | c71a1a3d | Iustin Pop | node1# ssh node3 |
568 | c71a1a3d | Iustin Pop | node3# kpartx -l /dev/… |
569 | c71a1a3d | Iustin Pop | node3# kpartx -a /dev/… |
570 | c71a1a3d | Iustin Pop | node3# mount /dev/mapper/… /mnt/ |
571 | c71a1a3d | Iustin Pop | # edit files under mnt as desired |
572 | c71a1a3d | Iustin Pop | node3# umount /mnt/ |
573 | c71a1a3d | Iustin Pop | node3# kpartx -d /dev/… |
574 | c71a1a3d | Iustin Pop | node3# exit |
575 | c71a1a3d | Iustin Pop | node1# |
576 | ffa6869f | Iustin Pop | |
577 | c71a1a3d | Iustin Pop | After you've finished you can deactivate them with the deactivate-disks |
578 | c71a1a3d | Iustin Pop | command, which works in the same way:: |
579 | c71a1a3d | Iustin Pop | |
580 | c71a1a3d | Iustin Pop | gnt-instance deactivate-disks INSTANCE |
581 | c71a1a3d | Iustin Pop | |
582 | c71a1a3d | Iustin Pop | Note that if any process started by you is still using the disks, the |
583 | c71a1a3d | Iustin Pop | above command will error out, and you **must** cleanup and ensure that |
584 | c71a1a3d | Iustin Pop | the above command runs successfully before you start the instance, |
585 | c71a1a3d | Iustin Pop | otherwise the instance will suffer corruption. |
586 | ffa6869f | Iustin Pop | |
587 | ffa6869f | Iustin Pop | Accessing an instance's console |
588 | fd07c6b3 | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
589 | ffa6869f | Iustin Pop | |
590 | ffa6869f | Iustin Pop | The command to access a running instance's console is:: |
591 | ffa6869f | Iustin Pop | |
592 | ffa6869f | Iustin Pop | gnt-instance console INSTANCE_NAME |
593 | ffa6869f | Iustin Pop | |
594 | c71a1a3d | Iustin Pop | Use the console normally and then type ``^]`` when done, to exit. |
595 | c71a1a3d | Iustin Pop | |
596 | c71a1a3d | Iustin Pop | Other instance operations |
597 | c71a1a3d | Iustin Pop | +++++++++++++++++++++++++ |
598 | c71a1a3d | Iustin Pop | |
599 | c71a1a3d | Iustin Pop | Reboot |
600 | c71a1a3d | Iustin Pop | ~~~~~~ |
601 | ffa6869f | Iustin Pop | |
602 | c71a1a3d | Iustin Pop | There is a wrapper command for rebooting instances:: |
603 | ffa6869f | Iustin Pop | |
604 | c71a1a3d | Iustin Pop | gnt-instance reboot instance2 |
605 | c71a1a3d | Iustin Pop | |
606 | c71a1a3d | Iustin Pop | By default, this does the equivalent of shutting down and then starting |
607 | c71a1a3d | Iustin Pop | the instance, but it accepts parameters to perform a soft-reboot (via |
608 | c71a1a3d | Iustin Pop | the hypervisor), a hard reboot (hypervisor shutdown and then startup) or |
609 | c71a1a3d | Iustin Pop | a full one (the default, which also de-configures and then configures |
610 | c71a1a3d | Iustin Pop | again the disks of the instance). |
611 | c71a1a3d | Iustin Pop | |
612 | c71a1a3d | Iustin Pop | Instance OS definitions debugging |
613 | c71a1a3d | Iustin Pop | +++++++++++++++++++++++++++++++++ |
614 | c71a1a3d | Iustin Pop | |
615 | c71a1a3d | Iustin Pop | Should you have any problems with instance operating systems the command |
616 | c71a1a3d | Iustin Pop | to see a complete status for all your nodes is:: |
617 | ffa6869f | Iustin Pop | |
618 | ffa6869f | Iustin Pop | gnt-os diagnose |
619 | ffa6869f | Iustin Pop | |
620 | c71a1a3d | Iustin Pop | .. _instance-relocation-label: |
621 | ffa6869f | Iustin Pop | |
622 | c71a1a3d | Iustin Pop | Instance relocation |
623 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~ |
624 | ffa6869f | Iustin Pop | |
625 | c71a1a3d | Iustin Pop | While it is not possible to move an instance from nodes ``(A, B)`` to |
626 | c71a1a3d | Iustin Pop | nodes ``(C, D)`` in a single move, it is possible to do so in a few |
627 | c71a1a3d | Iustin Pop | steps:: |
628 | ffa6869f | Iustin Pop | |
629 | c71a1a3d | Iustin Pop | # instance is located on A, B |
630 | c71a1a3d | Iustin Pop | node1# gnt-instance replace -n nodeC instance1 |
631 | c71a1a3d | Iustin Pop | # instance has moved from (A, B) to (A, C) |
632 | c71a1a3d | Iustin Pop | # we now flip the primary/secondary nodes |
633 | c71a1a3d | Iustin Pop | node1# gnt-instance migrate instance1 |
634 | c71a1a3d | Iustin Pop | # instance lives on (C, A) |
635 | c71a1a3d | Iustin Pop | # we can then change A to D via: |
636 | c71a1a3d | Iustin Pop | node1# gnt-instance replace -n nodeD instance1 |
637 | 56c9a709 | Iustin Pop | |
638 | c71a1a3d | Iustin Pop | Which brings it into the final configuration of ``(C, D)``. Note that we |
639 | c71a1a3d | Iustin Pop | needed to do two replace-disks operation (two copies of the instance |
640 | c71a1a3d | Iustin Pop | disks), because we needed to get rid of both the original nodes (A and |
641 | c71a1a3d | Iustin Pop | B). |
642 | c71a1a3d | Iustin Pop | |
643 | c71a1a3d | Iustin Pop | Node operations |
644 | c71a1a3d | Iustin Pop | --------------- |
645 | c71a1a3d | Iustin Pop | |
646 | c71a1a3d | Iustin Pop | There are much fewer node operations available than for instances, but |
647 | c71a1a3d | Iustin Pop | they are equivalently important for maintaining a healthy cluster. |
648 | c71a1a3d | Iustin Pop | |
649 | c71a1a3d | Iustin Pop | Add/readd |
650 | c71a1a3d | Iustin Pop | +++++++++ |
651 | c71a1a3d | Iustin Pop | |
652 | c71a1a3d | Iustin Pop | It is at any time possible to extend the cluster with one more node, by |
653 | c71a1a3d | Iustin Pop | using the node add operation:: |
654 | c71a1a3d | Iustin Pop | |
655 | c71a1a3d | Iustin Pop | gnt-node add NEW_NODE |
656 | c71a1a3d | Iustin Pop | |
657 | c71a1a3d | Iustin Pop | If the cluster has a replication network defined, then you need to pass |
658 | c71a1a3d | Iustin Pop | the ``-s REPLICATION_IP`` parameter to this option. |
659 | c71a1a3d | Iustin Pop | |
660 | c71a1a3d | Iustin Pop | A variation of this command can be used to re-configure a node if its |
661 | c71a1a3d | Iustin Pop | Ganeti configuration is broken, for example if it has been reinstalled |
662 | c71a1a3d | Iustin Pop | by mistake:: |
663 | c71a1a3d | Iustin Pop | |
664 | c71a1a3d | Iustin Pop | gnt-node add --readd EXISTING_NODE |
665 | c71a1a3d | Iustin Pop | |
666 | c71a1a3d | Iustin Pop | This will reinitialise the node as if it's been newly added, but while |
667 | c71a1a3d | Iustin Pop | keeping its existing configuration in the cluster (primary/secondary IP, |
668 | c71a1a3d | Iustin Pop | etc.), in other words you won't need to use ``-s`` here. |
669 | c71a1a3d | Iustin Pop | |
670 | c71a1a3d | Iustin Pop | Changing the node role |
671 | c71a1a3d | Iustin Pop | ++++++++++++++++++++++ |
672 | c71a1a3d | Iustin Pop | |
673 | c71a1a3d | Iustin Pop | A node can be in different roles, as explained in the |
674 | c71a1a3d | Iustin Pop | :ref:`terminology-label` section. Promoting a node to the master role is |
675 | c71a1a3d | Iustin Pop | special, while the other roles are handled all via a single command. |
676 | c71a1a3d | Iustin Pop | |
677 | c71a1a3d | Iustin Pop | Failing over the master node |
678 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
679 | c71a1a3d | Iustin Pop | |
680 | c71a1a3d | Iustin Pop | If you want to promote a different node to the master role (for whatever |
681 | c71a1a3d | Iustin Pop | reason), run on any other master-candidate node the command:: |
682 | c71a1a3d | Iustin Pop | |
683 | c71a1a3d | Iustin Pop | gnt-cluster masterfailover |
684 | c71a1a3d | Iustin Pop | |
685 | c71a1a3d | Iustin Pop | and the node you ran it on is now the new master. In case you try to run |
686 | c71a1a3d | Iustin Pop | this on a non master-candidate node, you will get an error telling you |
687 | c71a1a3d | Iustin Pop | which nodes are valid. |
688 | c71a1a3d | Iustin Pop | |
689 | c71a1a3d | Iustin Pop | Changing between the other roles |
690 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
691 | c71a1a3d | Iustin Pop | |
692 | c71a1a3d | Iustin Pop | The ``gnt-node modify`` command can be used to select a new role:: |
693 | c71a1a3d | Iustin Pop | |
694 | c71a1a3d | Iustin Pop | # change to master candidate |
695 | c71a1a3d | Iustin Pop | gnt-node modify -C yes NODE |
696 | c71a1a3d | Iustin Pop | # change to drained status |
697 | c71a1a3d | Iustin Pop | gnt-node modify -D yes NODE |
698 | c71a1a3d | Iustin Pop | # change to offline status |
699 | c71a1a3d | Iustin Pop | gnt-node modify -O yes NODE |
700 | c71a1a3d | Iustin Pop | # change to regular mode (reset all flags) |
701 | c71a1a3d | Iustin Pop | gnt-node modify -O no -D no -C no NODE |
702 | c71a1a3d | Iustin Pop | |
703 | c71a1a3d | Iustin Pop | Note that the cluster requires that at any point in time, a certain |
704 | c71a1a3d | Iustin Pop | number of nodes are master candidates, so changing from master candidate |
705 | c71a1a3d | Iustin Pop | to other roles might fail. It is recommended to either force the |
706 | c71a1a3d | Iustin Pop | operation (via the ``--force`` option) or first change the number of |
707 | c71a1a3d | Iustin Pop | master candidates in the cluster - see :ref:`cluster-config-label`. |
708 | c71a1a3d | Iustin Pop | |
709 | c71a1a3d | Iustin Pop | Evacuating nodes |
710 | c71a1a3d | Iustin Pop | ++++++++++++++++ |
711 | c71a1a3d | Iustin Pop | |
712 | c71a1a3d | Iustin Pop | There are two steps of moving instances off a node: |
713 | c71a1a3d | Iustin Pop | |
714 | c71a1a3d | Iustin Pop | - moving the primary instances (actually converting them into secondary |
715 | c71a1a3d | Iustin Pop | instances) |
716 | c71a1a3d | Iustin Pop | - moving the secondary instances (including any instances converted in |
717 | c71a1a3d | Iustin Pop | the step above) |
718 | c71a1a3d | Iustin Pop | |
719 | c71a1a3d | Iustin Pop | Primary instance conversion |
720 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
721 | c71a1a3d | Iustin Pop | |
722 | c71a1a3d | Iustin Pop | For this step, you can use either individual instance move |
723 | c71a1a3d | Iustin Pop | commands (as seen in :ref:`instance-change-primary-label`) or the bulk |
724 | c71a1a3d | Iustin Pop | per-node versions; these are:: |
725 | c71a1a3d | Iustin Pop | |
726 | c71a1a3d | Iustin Pop | gnt-node migrate NODE |
727 | c71a1a3d | Iustin Pop | gnt-node evacuate NODE |
728 | c71a1a3d | Iustin Pop | |
729 | c71a1a3d | Iustin Pop | Note that the instance “move” command doesn't currently have a node |
730 | c71a1a3d | Iustin Pop | equivalent. |
731 | c71a1a3d | Iustin Pop | |
732 | c71a1a3d | Iustin Pop | Both these commands, or the equivalent per-instance command, will make |
733 | c71a1a3d | Iustin Pop | this node the secondary node for the respective instances, whereas their |
734 | c71a1a3d | Iustin Pop | current secondary node will become primary. Note that it is not possible |
735 | c71a1a3d | Iustin Pop | to change in one step the primary node to another node as primary, while |
736 | c71a1a3d | Iustin Pop | keeping the same secondary node. |
737 | c71a1a3d | Iustin Pop | |
738 | c71a1a3d | Iustin Pop | Secondary instance evacuation |
739 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
740 | c71a1a3d | Iustin Pop | |
741 | c71a1a3d | Iustin Pop | For the evacuation of secondary instances, a command called |
742 | c71a1a3d | Iustin Pop | :command:`gnt-node evacuate` is provided and its syntax is:: |
743 | c71a1a3d | Iustin Pop | |
744 | c71a1a3d | Iustin Pop | gnt-node evacuate -I IALLOCATOR_SCRIPT NODE |
745 | c71a1a3d | Iustin Pop | gnt-node evacuate -n DESTINATION_NODE NODE |
746 | c71a1a3d | Iustin Pop | |
747 | c71a1a3d | Iustin Pop | The first version will compute the new secondary for each instance in |
748 | c71a1a3d | Iustin Pop | turn using the given iallocator script, whereas the second one will |
749 | c71a1a3d | Iustin Pop | simply move all instances to DESTINATION_NODE. |
750 | c71a1a3d | Iustin Pop | |
751 | c71a1a3d | Iustin Pop | Removal |
752 | c71a1a3d | Iustin Pop | +++++++ |
753 | c71a1a3d | Iustin Pop | |
754 | c71a1a3d | Iustin Pop | Once a node no longer has any instances (neither primary nor secondary), |
755 | c71a1a3d | Iustin Pop | it's easy to remove it from the cluster:: |
756 | c71a1a3d | Iustin Pop | |
757 | c71a1a3d | Iustin Pop | gnt-node remove NODE_NAME |
758 | c71a1a3d | Iustin Pop | |
759 | c71a1a3d | Iustin Pop | This will deconfigure the node, stop the ganeti daemons on it and leave |
760 | c71a1a3d | Iustin Pop | it hopefully like before it joined to the cluster. |
761 | c71a1a3d | Iustin Pop | |
762 | c71a1a3d | Iustin Pop | Storage handling |
763 | c71a1a3d | Iustin Pop | ++++++++++++++++ |
764 | c71a1a3d | Iustin Pop | |
765 | c71a1a3d | Iustin Pop | When using LVM (either standalone or with DRBD), it can become tedious |
766 | c71a1a3d | Iustin Pop | to debug and fix it in case of errors. Furthermore, even file-based |
767 | c71a1a3d | Iustin Pop | storage can become complicated to handle manually on many hosts. Ganeti |
768 | c71a1a3d | Iustin Pop | provides a couple of commands to help with automation. |
769 | c71a1a3d | Iustin Pop | |
770 | c71a1a3d | Iustin Pop | Logical volumes |
771 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~ |
772 | c71a1a3d | Iustin Pop | |
773 | c71a1a3d | Iustin Pop | This is a command specific to LVM handling. It allows listing the |
774 | c71a1a3d | Iustin Pop | logical volumes on a given node or on all nodes and their association to |
775 | c71a1a3d | Iustin Pop | instances via the ``volumes`` command:: |
776 | c71a1a3d | Iustin Pop | |
777 | c71a1a3d | Iustin Pop | node1# gnt-node volumes |
778 | c71a1a3d | Iustin Pop | Node PhysDev VG Name Size Instance |
779 | c71a1a3d | Iustin Pop | node1 /dev/sdb1 xenvg e61fbc97-….disk0 512M instance17 |
780 | c71a1a3d | Iustin Pop | node1 /dev/sdb1 xenvg ebd1a7d1-….disk0 512M instance19 |
781 | c71a1a3d | Iustin Pop | node2 /dev/sdb1 xenvg 0af08a3d-….disk0 512M instance20 |
782 | c71a1a3d | Iustin Pop | node2 /dev/sdb1 xenvg cc012285-….disk0 512M instance16 |
783 | c71a1a3d | Iustin Pop | node2 /dev/sdb1 xenvg f0fac192-….disk0 512M instance18 |
784 | c71a1a3d | Iustin Pop | |
785 | c71a1a3d | Iustin Pop | The above command maps each logical volume to a volume group and |
786 | c71a1a3d | Iustin Pop | underlying physical volume and (possibly) to an instance. |
787 | c71a1a3d | Iustin Pop | |
788 | c71a1a3d | Iustin Pop | .. _storage-units-label: |
789 | c71a1a3d | Iustin Pop | |
790 | c71a1a3d | Iustin Pop | Generalized storage handling |
791 | c71a1a3d | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
792 | c71a1a3d | Iustin Pop | |
793 | c71a1a3d | Iustin Pop | .. versionadded:: 2.1 |
794 | c71a1a3d | Iustin Pop | |
795 | c71a1a3d | Iustin Pop | Starting with Ganeti 2.1, a new storage framework has been implemented |
796 | c71a1a3d | Iustin Pop | that tries to abstract the handling of the storage type the cluster |
797 | c71a1a3d | Iustin Pop | uses. |
798 | c71a1a3d | Iustin Pop | |
799 | c71a1a3d | Iustin Pop | First is listing the backend storage and their space situation:: |
800 | c71a1a3d | Iustin Pop | |
801 | c71a1a3d | Iustin Pop | node1# gnt-node list-storage |
802 | c71a1a3d | Iustin Pop | Node Name Size Used Free |
803 | c71a1a3d | Iustin Pop | node1 /dev/sda7 673.8G 0M 673.8G |
804 | c71a1a3d | Iustin Pop | node1 /dev/sdb1 698.6G 1.5G 697.1G |
805 | c71a1a3d | Iustin Pop | node2 /dev/sda7 673.8G 0M 673.8G |
806 | c71a1a3d | Iustin Pop | node2 /dev/sdb1 698.6G 1.0G 697.6G |
807 | c71a1a3d | Iustin Pop | |
808 | c71a1a3d | Iustin Pop | The default is to list LVM physical volumes. It's also possible to list |
809 | c71a1a3d | Iustin Pop | the LVM volume groups:: |
810 | c71a1a3d | Iustin Pop | |
811 | c71a1a3d | Iustin Pop | node1# gnt-node list-storage -t lvm-vg |
812 | c71a1a3d | Iustin Pop | Node Name Size |
813 | c71a1a3d | Iustin Pop | node1 xenvg 1.3T |
814 | c71a1a3d | Iustin Pop | node2 xenvg 1.3T |
815 | c71a1a3d | Iustin Pop | |
816 | c71a1a3d | Iustin Pop | Next is repairing storage units, which is currently only implemented for |
817 | c71a1a3d | Iustin Pop | volume groups and does the equivalent of ``vgreduce --removemissing``:: |
818 | c71a1a3d | Iustin Pop | |
819 | c71a1a3d | Iustin Pop | node1# gnt-node repair-storage node2 lvm-vg xenvg |
820 | c71a1a3d | Iustin Pop | Sun Oct 25 22:21:45 2009 Repairing storage unit 'xenvg' on node2 ... |
821 | c71a1a3d | Iustin Pop | |
822 | c71a1a3d | Iustin Pop | Last is the modification of volume properties, which is (again) only |
823 | c71a1a3d | Iustin Pop | implemented for LVM physical volumes and allows toggling the |
824 | c71a1a3d | Iustin Pop | ``allocatable`` value:: |
825 | c71a1a3d | Iustin Pop | |
826 | c71a1a3d | Iustin Pop | node1# gnt-node modify-storage --allocatable=no node2 lvm-pv /dev/sdb1 |
827 | c71a1a3d | Iustin Pop | |
828 | c71a1a3d | Iustin Pop | Use of the storage commands |
829 | 56c9a709 | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
830 | 56c9a709 | Iustin Pop | |
831 | c71a1a3d | Iustin Pop | All these commands are needed when recovering a node from a disk |
832 | c71a1a3d | Iustin Pop | failure: |
833 | c71a1a3d | Iustin Pop | |
834 | c71a1a3d | Iustin Pop | - first, we need to recover from complete LVM failure (due to missing |
835 | c71a1a3d | Iustin Pop | disk), by running the ``repair-storage`` command |
836 | c71a1a3d | Iustin Pop | - second, we need to change allocation on any partially-broken disk |
837 | c71a1a3d | Iustin Pop | (i.e. LVM still sees it, but it has bad blocks) by running |
838 | c71a1a3d | Iustin Pop | ``modify-storage`` |
839 | c71a1a3d | Iustin Pop | - then we can evacuate the instances as needed |
840 | 56c9a709 | Iustin Pop | |
841 | 56c9a709 | Iustin Pop | |
842 | c71a1a3d | Iustin Pop | Cluster operations |
843 | c71a1a3d | Iustin Pop | ------------------ |
844 | c71a1a3d | Iustin Pop | |
845 | c71a1a3d | Iustin Pop | Beside the cluster initialisation command (which is detailed in the |
846 | c71a1a3d | Iustin Pop | :doc:`install` document) and the master failover command which is |
847 | c71a1a3d | Iustin Pop | explained under node handling, there are a couple of other cluster |
848 | c71a1a3d | Iustin Pop | operations available. |
849 | c71a1a3d | Iustin Pop | |
850 | c71a1a3d | Iustin Pop | .. _cluster-config-label: |
851 | c71a1a3d | Iustin Pop | |
852 | c71a1a3d | Iustin Pop | Standard operations |
853 | c71a1a3d | Iustin Pop | +++++++++++++++++++ |
854 | c71a1a3d | Iustin Pop | |
855 | c71a1a3d | Iustin Pop | One of the few commands that can be run on any node (not only the |
856 | c71a1a3d | Iustin Pop | master) is the ``getmaster`` command:: |
857 | c71a1a3d | Iustin Pop | |
858 | c71a1a3d | Iustin Pop | node2# gnt-cluster getmaster |
859 | c71a1a3d | Iustin Pop | node1.example.com |
860 | c71a1a3d | Iustin Pop | node2# |
861 | c71a1a3d | Iustin Pop | |
862 | c71a1a3d | Iustin Pop | It is possible to query and change global cluster parameters via the |
863 | c71a1a3d | Iustin Pop | ``info`` and ``modify`` commands:: |
864 | c71a1a3d | Iustin Pop | |
865 | c71a1a3d | Iustin Pop | node1# gnt-cluster info |
866 | c71a1a3d | Iustin Pop | Cluster name: cluster.example.com |
867 | c71a1a3d | Iustin Pop | Cluster UUID: 07805e6f-f0af-4310-95f1-572862ee939c |
868 | c71a1a3d | Iustin Pop | Creation time: 2009-09-25 05:04:15 |
869 | c71a1a3d | Iustin Pop | Modification time: 2009-10-18 22:11:47 |
870 | c71a1a3d | Iustin Pop | Master node: node1.example.com |
871 | c71a1a3d | Iustin Pop | Architecture (this node): 64bit (x86_64) |
872 | c71a1a3d | Iustin Pop | … |
873 | c71a1a3d | Iustin Pop | Tags: foo |
874 | c71a1a3d | Iustin Pop | Default hypervisor: xen-pvm |
875 | c71a1a3d | Iustin Pop | Enabled hypervisors: xen-pvm |
876 | c71a1a3d | Iustin Pop | Hypervisor parameters: |
877 | c71a1a3d | Iustin Pop | - xen-pvm: |
878 | c71a1a3d | Iustin Pop | root_path: /dev/sda1 |
879 | c71a1a3d | Iustin Pop | … |
880 | c71a1a3d | Iustin Pop | Cluster parameters: |
881 | c71a1a3d | Iustin Pop | - candidate pool size: 10 |
882 | c71a1a3d | Iustin Pop | … |
883 | c71a1a3d | Iustin Pop | Default instance parameters: |
884 | c71a1a3d | Iustin Pop | - default: |
885 | c71a1a3d | Iustin Pop | memory: 128 |
886 | c71a1a3d | Iustin Pop | … |
887 | c71a1a3d | Iustin Pop | Default nic parameters: |
888 | c71a1a3d | Iustin Pop | - default: |
889 | c71a1a3d | Iustin Pop | link: xen-br0 |
890 | c71a1a3d | Iustin Pop | … |
891 | c71a1a3d | Iustin Pop | |
892 | c71a1a3d | Iustin Pop | There various parameters above can be changed via the ``modify`` |
893 | c71a1a3d | Iustin Pop | commands as follows: |
894 | c71a1a3d | Iustin Pop | |
895 | c71a1a3d | Iustin Pop | - the hypervisor parameters can be changed via ``modify -H |
896 | c71a1a3d | Iustin Pop | xen-pvm:root_path=…``, and so on for other hypervisors/key/values |
897 | c71a1a3d | Iustin Pop | - the "default instance parameters" are changeable via ``modify -B |
898 | c71a1a3d | Iustin Pop | parameter=value…`` syntax |
899 | c71a1a3d | Iustin Pop | - the cluster parameters are changeable via separate options to the |
900 | c71a1a3d | Iustin Pop | modify command (e.g. ``--candidate-pool-size``, etc.) |
901 | c71a1a3d | Iustin Pop | |
902 | c71a1a3d | Iustin Pop | For detailed option list see the :manpage:`gnt-cluster(8)` man page. |
903 | c71a1a3d | Iustin Pop | |
904 | c71a1a3d | Iustin Pop | The cluster version can be obtained via the ``version`` command:: |
905 | c71a1a3d | Iustin Pop | node1# gnt-cluster version |
906 | c71a1a3d | Iustin Pop | Software version: 2.1.0 |
907 | c71a1a3d | Iustin Pop | Internode protocol: 20 |
908 | c71a1a3d | Iustin Pop | Configuration format: 2010000 |
909 | c71a1a3d | Iustin Pop | OS api version: 15 |
910 | c71a1a3d | Iustin Pop | Export interface: 0 |
911 | c71a1a3d | Iustin Pop | |
912 | c71a1a3d | Iustin Pop | This is not very useful except when debugging Ganeti. |
913 | c71a1a3d | Iustin Pop | |
914 | c71a1a3d | Iustin Pop | Global node commands |
915 | c71a1a3d | Iustin Pop | ++++++++++++++++++++ |
916 | c71a1a3d | Iustin Pop | |
917 | c71a1a3d | Iustin Pop | There are two commands provided for replicating files to all nodes of a |
918 | c71a1a3d | Iustin Pop | cluster and for running commands on all the nodes:: |
919 | c71a1a3d | Iustin Pop | |
920 | c71a1a3d | Iustin Pop | node1# gnt-cluster copyfile /path/to/file |
921 | c71a1a3d | Iustin Pop | node1# gnt-cluster command ls -l /path/to/file |
922 | c71a1a3d | Iustin Pop | |
923 | c71a1a3d | Iustin Pop | These are simple wrappers over scp/ssh and more advanced usage can be |
924 | c71a1a3d | Iustin Pop | obtained using :manpage:`dsh(1)` and similar commands. But they are |
925 | c71a1a3d | Iustin Pop | useful to update an OS script from the master node, for example. |
926 | c71a1a3d | Iustin Pop | |
927 | c71a1a3d | Iustin Pop | Cluster verification |
928 | c71a1a3d | Iustin Pop | ++++++++++++++++++++ |
929 | c71a1a3d | Iustin Pop | |
930 | c71a1a3d | Iustin Pop | There are three commands that relate to global cluster checks. The first |
931 | c71a1a3d | Iustin Pop | one is ``verify`` which gives an overview on the cluster state, |
932 | c71a1a3d | Iustin Pop | highlighting any issues. In normal operation, this command should return |
933 | c71a1a3d | Iustin Pop | no ``ERROR`` messages:: |
934 | c71a1a3d | Iustin Pop | |
935 | c71a1a3d | Iustin Pop | node1# gnt-cluster verify |
936 | c71a1a3d | Iustin Pop | Sun Oct 25 23:08:58 2009 * Verifying global settings |
937 | c71a1a3d | Iustin Pop | Sun Oct 25 23:08:58 2009 * Gathering data (2 nodes) |
938 | c71a1a3d | Iustin Pop | Sun Oct 25 23:09:00 2009 * Verifying node status |
939 | c71a1a3d | Iustin Pop | Sun Oct 25 23:09:00 2009 * Verifying instance status |
940 | c71a1a3d | Iustin Pop | Sun Oct 25 23:09:00 2009 * Verifying orphan volumes |
941 | c71a1a3d | Iustin Pop | Sun Oct 25 23:09:00 2009 * Verifying remaining instances |
942 | c71a1a3d | Iustin Pop | Sun Oct 25 23:09:00 2009 * Verifying N+1 Memory redundancy |
943 | c71a1a3d | Iustin Pop | Sun Oct 25 23:09:00 2009 * Other Notes |
944 | c71a1a3d | Iustin Pop | Sun Oct 25 23:09:00 2009 - NOTICE: 5 non-redundant instance(s) found. |
945 | c71a1a3d | Iustin Pop | Sun Oct 25 23:09:00 2009 * Hooks Results |
946 | c71a1a3d | Iustin Pop | |
947 | c71a1a3d | Iustin Pop | The second command is ``verify-disks``, which checks that the instance's |
948 | c71a1a3d | Iustin Pop | disks have the correct status based on the desired instance state |
949 | c71a1a3d | Iustin Pop | (up/down):: |
950 | c71a1a3d | Iustin Pop | |
951 | c71a1a3d | Iustin Pop | node1# gnt-cluster verify-disks |
952 | c71a1a3d | Iustin Pop | |
953 | c71a1a3d | Iustin Pop | Note that this command will show no output when disks are healthy. |
954 | c71a1a3d | Iustin Pop | |
955 | c71a1a3d | Iustin Pop | The last command is used to repair any discrepancies in Ganeti's |
956 | c71a1a3d | Iustin Pop | recorded disk size and the actual disk size (disk size information is |
957 | c71a1a3d | Iustin Pop | needed for proper activation and growth of DRBD-based disks):: |
958 | c71a1a3d | Iustin Pop | |
959 | c71a1a3d | Iustin Pop | node1# gnt-cluster repair-disk-sizes |
960 | c71a1a3d | Iustin Pop | Sun Oct 25 23:13:16 2009 - INFO: Disk 0 of instance instance1 has mismatched size, correcting: recorded 512, actual 2048 |
961 | c71a1a3d | Iustin Pop | Sun Oct 25 23:13:17 2009 - WARNING: Invalid result from node node4, ignoring node results |
962 | c71a1a3d | Iustin Pop | |
963 | c71a1a3d | Iustin Pop | The above shows one instance having wrong disk size, and a node which |
964 | c71a1a3d | Iustin Pop | returned invalid data, and thus we ignored all primary instances of that |
965 | c71a1a3d | Iustin Pop | node. |
966 | c71a1a3d | Iustin Pop | |
967 | c71a1a3d | Iustin Pop | Configuration redistribution |
968 | c71a1a3d | Iustin Pop | ++++++++++++++++++++++++++++ |
969 | c71a1a3d | Iustin Pop | |
970 | c71a1a3d | Iustin Pop | If the verify command complains about file mismatches between the master |
971 | c71a1a3d | Iustin Pop | and other nodes, due to some node problems or if you manually modified |
972 | c71a1a3d | Iustin Pop | configuration files, you can force an push of the master configuration |
973 | c71a1a3d | Iustin Pop | to all other nodes via the ``redist-conf`` command:: |
974 | c71a1a3d | Iustin Pop | |
975 | c71a1a3d | Iustin Pop | node1# gnt-cluster redist-conf |
976 | c71a1a3d | Iustin Pop | node1# |
977 | c71a1a3d | Iustin Pop | |
978 | c71a1a3d | Iustin Pop | This command will be silent unless there are problems sending updates to |
979 | c71a1a3d | Iustin Pop | the other nodes. |
980 | c71a1a3d | Iustin Pop | |
981 | c71a1a3d | Iustin Pop | |
982 | c71a1a3d | Iustin Pop | Cluster renaming |
983 | c71a1a3d | Iustin Pop | ++++++++++++++++ |
984 | c71a1a3d | Iustin Pop | |
985 | c71a1a3d | Iustin Pop | It is possible to rename a cluster, or to change its IP address, via the |
986 | c71a1a3d | Iustin Pop | ``rename`` command. If only the IP has changed, you need to pass the |
987 | c71a1a3d | Iustin Pop | current name and Ganeti will realise its IP has changed:: |
988 | c71a1a3d | Iustin Pop | |
989 | c71a1a3d | Iustin Pop | node1# gnt-cluster rename cluster.example.com |
990 | c71a1a3d | Iustin Pop | This will rename the cluster to 'cluster.example.com'. If |
991 | c71a1a3d | Iustin Pop | you are connected over the network to the cluster name, the operation |
992 | c71a1a3d | Iustin Pop | is very dangerous as the IP address will be removed from the node and |
993 | c71a1a3d | Iustin Pop | the change may not go through. Continue? |
994 | c71a1a3d | Iustin Pop | y/[n]/?: y |
995 | c71a1a3d | Iustin Pop | Failure: prerequisites not met for this operation: |
996 | c71a1a3d | Iustin Pop | Neither the name nor the IP address of the cluster has changed |
997 | c71a1a3d | Iustin Pop | |
998 | c71a1a3d | Iustin Pop | In the above output, neither value has changed since the cluster |
999 | c71a1a3d | Iustin Pop | initialisation so the operation is not completed. |
1000 | c71a1a3d | Iustin Pop | |
1001 | c71a1a3d | Iustin Pop | Queue operations |
1002 | c71a1a3d | Iustin Pop | ++++++++++++++++ |
1003 | c71a1a3d | Iustin Pop | |
1004 | c71a1a3d | Iustin Pop | The job queue execution in Ganeti 2.0 and higher can be inspected, |
1005 | c71a1a3d | Iustin Pop | suspended and resumed via the ``queue`` command:: |
1006 | c71a1a3d | Iustin Pop | |
1007 | c71a1a3d | Iustin Pop | node1~# gnt-cluster queue info |
1008 | c71a1a3d | Iustin Pop | The drain flag is unset |
1009 | c71a1a3d | Iustin Pop | node1~# gnt-cluster queue drain |
1010 | c71a1a3d | Iustin Pop | node1~# gnt-instance stop instance1 |
1011 | c71a1a3d | Iustin Pop | Failed to submit job for instance1: Job queue is drained, refusing job |
1012 | c71a1a3d | Iustin Pop | node1~# gnt-cluster queue info |
1013 | c71a1a3d | Iustin Pop | The drain flag is set |
1014 | c71a1a3d | Iustin Pop | node1~# gnt-cluster queue undrain |
1015 | c71a1a3d | Iustin Pop | |
1016 | c71a1a3d | Iustin Pop | This is most useful if you have an active cluster and you need to |
1017 | c71a1a3d | Iustin Pop | upgrade the Ganeti software, or simply restart the software on any node: |
1018 | c71a1a3d | Iustin Pop | |
1019 | c71a1a3d | Iustin Pop | #. suspend the queue via ``queue drain`` |
1020 | c71a1a3d | Iustin Pop | #. wait until there are no more running jobs via ``gnt-job list`` |
1021 | c71a1a3d | Iustin Pop | #. restart the master or another node, or upgrade the software |
1022 | c71a1a3d | Iustin Pop | #. resume the queue via ``queue undrain`` |
1023 | c71a1a3d | Iustin Pop | |
1024 | c71a1a3d | Iustin Pop | .. note:: this command only stores a local flag file, and if you |
1025 | c71a1a3d | Iustin Pop | failover the master, it will not have effect on the new master. |
1026 | c71a1a3d | Iustin Pop | |
1027 | c71a1a3d | Iustin Pop | |
1028 | c71a1a3d | Iustin Pop | Watcher control |
1029 | c71a1a3d | Iustin Pop | +++++++++++++++ |
1030 | c71a1a3d | Iustin Pop | |
1031 | c71a1a3d | Iustin Pop | The :manpage:`ganeti-watcher` is a program, usually scheduled via |
1032 | c71a1a3d | Iustin Pop | ``cron``, that takes care of cluster maintenance operations (restarting |
1033 | c71a1a3d | Iustin Pop | downed instances, activating down DRBD disks, etc.). However, during |
1034 | c71a1a3d | Iustin Pop | maintenance and troubleshooting, this can get in your way; disabling it |
1035 | c71a1a3d | Iustin Pop | via commenting out the cron job is not so good as this can be |
1036 | c71a1a3d | Iustin Pop | forgotten. Thus there are some commands for automated control of the |
1037 | c71a1a3d | Iustin Pop | watcher: ``pause``, ``info`` and ``continue``:: |
1038 | c71a1a3d | Iustin Pop | |
1039 | c71a1a3d | Iustin Pop | node1~# gnt-cluster watcher info |
1040 | c71a1a3d | Iustin Pop | The watcher is not paused. |
1041 | c71a1a3d | Iustin Pop | node1~# gnt-cluster watcher pause 1h |
1042 | c71a1a3d | Iustin Pop | The watcher is paused until Mon Oct 26 00:30:37 2009. |
1043 | c71a1a3d | Iustin Pop | node1~# gnt-cluster watcher info |
1044 | c71a1a3d | Iustin Pop | The watcher is paused until Mon Oct 26 00:30:37 2009. |
1045 | c71a1a3d | Iustin Pop | node1~# ganeti-watcher -d |
1046 | c71a1a3d | Iustin Pop | 2009-10-25 23:30:47,984: pid=28867 ganeti-watcher:486 DEBUG Pause has been set, exiting |
1047 | c71a1a3d | Iustin Pop | node1~# gnt-cluster watcher continue |
1048 | c71a1a3d | Iustin Pop | The watcher is no longer paused. |
1049 | c71a1a3d | Iustin Pop | node1~# ganeti-watcher -d |
1050 | c71a1a3d | Iustin Pop | 2009-10-25 23:31:04,789: pid=28976 ganeti-watcher:345 DEBUG Archived 0 jobs, left 0 |
1051 | c71a1a3d | Iustin Pop | 2009-10-25 23:31:05,884: pid=28976 ganeti-watcher:280 DEBUG Got data from cluster, writing instance status file |
1052 | c71a1a3d | Iustin Pop | 2009-10-25 23:31:06,061: pid=28976 ganeti-watcher:150 DEBUG Data didn't change, just touching status file |
1053 | c71a1a3d | Iustin Pop | node1~# gnt-cluster watcher info |
1054 | c71a1a3d | Iustin Pop | The watcher is not paused. |
1055 | c71a1a3d | Iustin Pop | node1~# |
1056 | c71a1a3d | Iustin Pop | |
1057 | c71a1a3d | Iustin Pop | The exact details of the argument to the ``pause`` command are available |
1058 | c71a1a3d | Iustin Pop | in the manpage. |
1059 | c71a1a3d | Iustin Pop | |
1060 | c71a1a3d | Iustin Pop | .. note:: this command only stores a local flag file, and if you |
1061 | c71a1a3d | Iustin Pop | failover the master, it will not have effect on the new master. |
1062 | c71a1a3d | Iustin Pop | |
1063 | 6328fea3 | Iustin Pop | Node auto-maintenance |
1064 | 6328fea3 | Iustin Pop | +++++++++++++++++++++ |
1065 | 6328fea3 | Iustin Pop | |
1066 | 6328fea3 | Iustin Pop | If the cluster parameter ``maintain_node_health`` is enabled (see the |
1067 | 6328fea3 | Iustin Pop | manpage for :command:`gnt-cluster`, the init and modify subcommands), |
1068 | 6328fea3 | Iustin Pop | then the following will happen automatically: |
1069 | 6328fea3 | Iustin Pop | |
1070 | 6328fea3 | Iustin Pop | - the watcher will shutdown any instances running on offline nodes |
1071 | 6328fea3 | Iustin Pop | - the watcher will deactivate any DRBD devices on offline nodes |
1072 | 6328fea3 | Iustin Pop | |
1073 | 6328fea3 | Iustin Pop | In the future, more actions are planned, so only enable this parameter |
1074 | 6328fea3 | Iustin Pop | if the nodes are completely dedicated to Ganeti; otherwise it might be |
1075 | 6328fea3 | Iustin Pop | possible to lose data due to auto-maintenance actions. |
1076 | 6328fea3 | Iustin Pop | |
1077 | c71a1a3d | Iustin Pop | Removing a cluster entirely |
1078 | c71a1a3d | Iustin Pop | +++++++++++++++++++++++++++ |
1079 | c71a1a3d | Iustin Pop | |
1080 | c71a1a3d | Iustin Pop | The usual method to cleanup a cluster is to run ``gnt-cluster destroy`` |
1081 | c71a1a3d | Iustin Pop | however if the Ganeti installation is broken in any way then this will |
1082 | c71a1a3d | Iustin Pop | not run. |
1083 | c71a1a3d | Iustin Pop | |
1084 | c71a1a3d | Iustin Pop | It is possible in such a case to cleanup manually most if not all traces |
1085 | c71a1a3d | Iustin Pop | of a cluster installation by following these steps on all of the nodes: |
1086 | c71a1a3d | Iustin Pop | |
1087 | c71a1a3d | Iustin Pop | 1. Shutdown all instances. This depends on the virtualisation method |
1088 | c71a1a3d | Iustin Pop | used (Xen, KVM, etc.): |
1089 | 56c9a709 | Iustin Pop | |
1090 | 56c9a709 | Iustin Pop | - Xen: run ``xm list`` and ``xm destroy`` on all the non-Domain-0 |
1091 | 56c9a709 | Iustin Pop | instances |
1092 | 56c9a709 | Iustin Pop | - KVM: kill all the KVM processes |
1093 | 56c9a709 | Iustin Pop | - chroot: kill all processes under the chroot mountpoints |
1094 | 56c9a709 | Iustin Pop | |
1095 | c71a1a3d | Iustin Pop | 2. If using DRBD, shutdown all DRBD minors (which should by at this time |
1096 | c71a1a3d | Iustin Pop | no-longer in use by instances); on each node, run ``drbdsetup |
1097 | 56c9a709 | Iustin Pop | /dev/drbdN down`` for each active DRBD minor. |
1098 | 56c9a709 | Iustin Pop | |
1099 | c71a1a3d | Iustin Pop | 3. If using LVM, cleanup the Ganeti volume group; if only Ganeti created |
1100 | c71a1a3d | Iustin Pop | logical volumes (and you are not sharing the volume group with the |
1101 | c71a1a3d | Iustin Pop | OS, for example), then simply running ``lvremove -f xenvg`` (replace |
1102 | c71a1a3d | Iustin Pop | 'xenvg' with your volume group name) should do the required cleanup. |
1103 | 56c9a709 | Iustin Pop | |
1104 | 56c9a709 | Iustin Pop | 4. If using file-based storage, remove recursively all files and |
1105 | 56c9a709 | Iustin Pop | directories under your file-storage directory: ``rm -rf |
1106 | c71a1a3d | Iustin Pop | /srv/ganeti/file-storage/*`` replacing the path with the correct path |
1107 | c71a1a3d | Iustin Pop | for your cluster. |
1108 | 56c9a709 | Iustin Pop | |
1109 | 56c9a709 | Iustin Pop | 5. Stop the ganeti daemons (``/etc/init.d/ganeti stop``) and kill any |
1110 | 56c9a709 | Iustin Pop | that remain alive (``pgrep ganeti`` and ``pkill ganeti``). |
1111 | 56c9a709 | Iustin Pop | |
1112 | 56c9a709 | Iustin Pop | 6. Remove the ganeti state directory (``rm -rf /var/lib/ganeti/*``), |
1113 | 56c9a709 | Iustin Pop | replacing the path with the correct path for your installation. |
1114 | 56c9a709 | Iustin Pop | |
1115 | 56c9a709 | Iustin Pop | On the master node, remove the cluster from the master-netdev (usually |
1116 | c71a1a3d | Iustin Pop | ``xen-br0`` for bridged mode, otherwise ``eth0`` or similar), by running |
1117 | c71a1a3d | Iustin Pop | ``ip a del $clusterip/32 dev xen-br0`` (use the correct cluster ip and |
1118 | c71a1a3d | Iustin Pop | network device name). |
1119 | 56c9a709 | Iustin Pop | |
1120 | 56c9a709 | Iustin Pop | At this point, the machines are ready for a cluster creation; in case |
1121 | c71a1a3d | Iustin Pop | you want to remove Ganeti completely, you need to also undo some of the |
1122 | c71a1a3d | Iustin Pop | SSH changes and log directories: |
1123 | 56c9a709 | Iustin Pop | |
1124 | 7faf5110 | Michael Hanselmann | - ``rm -rf /var/log/ganeti /srv/ganeti`` (replace with the correct |
1125 | 7faf5110 | Michael Hanselmann | paths) |
1126 | c71a1a3d | Iustin Pop | - remove from ``/root/.ssh`` the keys that Ganeti added (check the |
1127 | c71a1a3d | Iustin Pop | ``authorized_keys`` and ``id_dsa`` files) |
1128 | 56c9a709 | Iustin Pop | - regenerate the host's SSH keys (check the OpenSSH startup scripts) |
1129 | 56c9a709 | Iustin Pop | - uninstall Ganeti |
1130 | 56c9a709 | Iustin Pop | |
1131 | 56c9a709 | Iustin Pop | Otherwise, if you plan to re-create the cluster, you can just go ahead |
1132 | 56c9a709 | Iustin Pop | and rerun ``gnt-cluster init``. |
1133 | 558fd122 | Michael Hanselmann | |
1134 | c71a1a3d | Iustin Pop | Tags handling |
1135 | c71a1a3d | Iustin Pop | ------------- |
1136 | c71a1a3d | Iustin Pop | |
1137 | c71a1a3d | Iustin Pop | The tags handling (addition, removal, listing) is similar for all the |
1138 | c71a1a3d | Iustin Pop | objects that support it (instances, nodes, and the cluster). |
1139 | c71a1a3d | Iustin Pop | |
1140 | c71a1a3d | Iustin Pop | Limitations |
1141 | c71a1a3d | Iustin Pop | +++++++++++ |
1142 | c71a1a3d | Iustin Pop | |
1143 | c71a1a3d | Iustin Pop | Note that the set of characters present in a tag and the maximum tag |
1144 | c71a1a3d | Iustin Pop | length are restricted. Currently the maximum length is 128 characters, |
1145 | c71a1a3d | Iustin Pop | there can be at most 4096 tags per object, and the set of characters is |
1146 | c71a1a3d | Iustin Pop | comprised by alphanumeric characters and additionally ``.+*/:-``. |
1147 | c71a1a3d | Iustin Pop | |
1148 | c71a1a3d | Iustin Pop | Operations |
1149 | c71a1a3d | Iustin Pop | ++++++++++ |
1150 | c71a1a3d | Iustin Pop | |
1151 | c71a1a3d | Iustin Pop | Tags can be added via ``add-tags``:: |
1152 | c71a1a3d | Iustin Pop | |
1153 | c71a1a3d | Iustin Pop | gnt-instance add-tags INSTANCE a b c |
1154 | c71a1a3d | Iustin Pop | gnt-node add-tags INSTANCE a b c |
1155 | c71a1a3d | Iustin Pop | gnt-cluster add-tags a b c |
1156 | c71a1a3d | Iustin Pop | |
1157 | c71a1a3d | Iustin Pop | |
1158 | c71a1a3d | Iustin Pop | The above commands add three tags to an instance, to a node and to the |
1159 | c71a1a3d | Iustin Pop | cluster. Note that the cluster command only takes tags as arguments, |
1160 | c71a1a3d | Iustin Pop | whereas the node and instance commands first required the node and |
1161 | c71a1a3d | Iustin Pop | instance name. |
1162 | c71a1a3d | Iustin Pop | |
1163 | c71a1a3d | Iustin Pop | Tags can also be added from a file, via the ``--from=FILENAME`` |
1164 | c71a1a3d | Iustin Pop | argument. The file is expected to contain one tag per line. |
1165 | c71a1a3d | Iustin Pop | |
1166 | c71a1a3d | Iustin Pop | Tags can also be remove via a syntax very similar to the add one:: |
1167 | c71a1a3d | Iustin Pop | |
1168 | c71a1a3d | Iustin Pop | gnt-instance remove-tags INSTANCE a b c |
1169 | c71a1a3d | Iustin Pop | |
1170 | c71a1a3d | Iustin Pop | And listed via:: |
1171 | c71a1a3d | Iustin Pop | |
1172 | c71a1a3d | Iustin Pop | gnt-instance list-tags |
1173 | c71a1a3d | Iustin Pop | gnt-node list-tags |
1174 | c71a1a3d | Iustin Pop | gnt-cluster list-tags |
1175 | c71a1a3d | Iustin Pop | |
1176 | c71a1a3d | Iustin Pop | Global tag search |
1177 | c71a1a3d | Iustin Pop | +++++++++++++++++ |
1178 | c71a1a3d | Iustin Pop | |
1179 | c71a1a3d | Iustin Pop | It is also possible to execute a global search on the all tags defined |
1180 | c71a1a3d | Iustin Pop | in the cluster configuration, via a cluster command:: |
1181 | c71a1a3d | Iustin Pop | |
1182 | c71a1a3d | Iustin Pop | gnt-cluster search-tags REGEXP |
1183 | c71a1a3d | Iustin Pop | |
1184 | c71a1a3d | Iustin Pop | The parameter expected is a regular expression (see |
1185 | c71a1a3d | Iustin Pop | :manpage:`regex(7)`). This will return all tags that match the search, |
1186 | c71a1a3d | Iustin Pop | together with the object they are defined in (the names being show in a |
1187 | c71a1a3d | Iustin Pop | hierarchical kind of way):: |
1188 | c71a1a3d | Iustin Pop | |
1189 | c71a1a3d | Iustin Pop | node1# gnt-cluster search-tags o |
1190 | c71a1a3d | Iustin Pop | /cluster foo |
1191 | c71a1a3d | Iustin Pop | /instances/instance1 owner:bar |
1192 | c71a1a3d | Iustin Pop | |
1193 | c71a1a3d | Iustin Pop | |
1194 | c71a1a3d | Iustin Pop | Job operations |
1195 | c71a1a3d | Iustin Pop | -------------- |
1196 | c71a1a3d | Iustin Pop | |
1197 | c71a1a3d | Iustin Pop | The various jobs submitted by the instance/node/cluster commands can be |
1198 | c71a1a3d | Iustin Pop | examined, canceled and archived by various invocations of the |
1199 | c71a1a3d | Iustin Pop | ``gnt-job`` command. |
1200 | c71a1a3d | Iustin Pop | |
1201 | c71a1a3d | Iustin Pop | First is the job list command:: |
1202 | c71a1a3d | Iustin Pop | |
1203 | c71a1a3d | Iustin Pop | node1# gnt-job list |
1204 | c71a1a3d | Iustin Pop | 17771 success INSTANCE_QUERY_DATA |
1205 | c71a1a3d | Iustin Pop | 17773 success CLUSTER_VERIFY_DISKS |
1206 | c71a1a3d | Iustin Pop | 17775 success CLUSTER_REPAIR_DISK_SIZES |
1207 | c71a1a3d | Iustin Pop | 17776 error CLUSTER_RENAME(cluster.example.com) |
1208 | c71a1a3d | Iustin Pop | 17780 success CLUSTER_REDIST_CONF |
1209 | c71a1a3d | Iustin Pop | 17792 success INSTANCE_REBOOT(instance1.example.com) |
1210 | c71a1a3d | Iustin Pop | |
1211 | c71a1a3d | Iustin Pop | More detailed information about a job can be found via the ``info`` |
1212 | c71a1a3d | Iustin Pop | command:: |
1213 | c71a1a3d | Iustin Pop | |
1214 | c71a1a3d | Iustin Pop | node1# gnt-job info 17776 |
1215 | c71a1a3d | Iustin Pop | Job ID: 17776 |
1216 | c71a1a3d | Iustin Pop | Status: error |
1217 | c71a1a3d | Iustin Pop | Received: 2009-10-25 23:18:02.180569 |
1218 | c71a1a3d | Iustin Pop | Processing start: 2009-10-25 23:18:02.200335 (delta 0.019766s) |
1219 | c71a1a3d | Iustin Pop | Processing end: 2009-10-25 23:18:02.279743 (delta 0.079408s) |
1220 | c71a1a3d | Iustin Pop | Total processing time: 0.099174 seconds |
1221 | c71a1a3d | Iustin Pop | Opcodes: |
1222 | c71a1a3d | Iustin Pop | OP_CLUSTER_RENAME |
1223 | c71a1a3d | Iustin Pop | Status: error |
1224 | c71a1a3d | Iustin Pop | Processing start: 2009-10-25 23:18:02.200335 |
1225 | c71a1a3d | Iustin Pop | Processing end: 2009-10-25 23:18:02.252282 |
1226 | c71a1a3d | Iustin Pop | Input fields: |
1227 | c71a1a3d | Iustin Pop | name: cluster.example.com |
1228 | c71a1a3d | Iustin Pop | Result: |
1229 | c71a1a3d | Iustin Pop | OpPrereqError |
1230 | c71a1a3d | Iustin Pop | [Neither the name nor the IP address of the cluster has changed] |
1231 | c71a1a3d | Iustin Pop | Execution log: |
1232 | c71a1a3d | Iustin Pop | |
1233 | c71a1a3d | Iustin Pop | During the execution of a job, it's possible to follow the output of a |
1234 | c71a1a3d | Iustin Pop | job, similar to the log that one get from the ``gnt-`` commands, via the |
1235 | c71a1a3d | Iustin Pop | watch command:: |
1236 | c71a1a3d | Iustin Pop | |
1237 | c71a1a3d | Iustin Pop | node1# gnt-instance add --submit … instance1 |
1238 | c71a1a3d | Iustin Pop | JobID: 17818 |
1239 | c71a1a3d | Iustin Pop | node1# gnt-job watch 17818 |
1240 | c71a1a3d | Iustin Pop | Output from job 17818 follows |
1241 | c71a1a3d | Iustin Pop | ----------------------------- |
1242 | c71a1a3d | Iustin Pop | Mon Oct 26 00:22:48 2009 - INFO: Selected nodes for instance instance1 via iallocator dumb: node1, node2 |
1243 | c71a1a3d | Iustin Pop | Mon Oct 26 00:22:49 2009 * creating instance disks... |
1244 | c71a1a3d | Iustin Pop | Mon Oct 26 00:22:52 2009 adding instance instance1 to cluster config |
1245 | c71a1a3d | Iustin Pop | Mon Oct 26 00:22:52 2009 - INFO: Waiting for instance instance1 to sync disks. |
1246 | c71a1a3d | Iustin Pop | … |
1247 | c71a1a3d | Iustin Pop | Mon Oct 26 00:23:03 2009 creating os for instance xen-devi-18.fra.corp.google.com on node mpgntac4.fra.corp.google.com |
1248 | c71a1a3d | Iustin Pop | Mon Oct 26 00:23:03 2009 * running the instance OS create scripts... |
1249 | c71a1a3d | Iustin Pop | Mon Oct 26 00:23:13 2009 * starting instance... |
1250 | c71a1a3d | Iustin Pop | node1# |
1251 | c71a1a3d | Iustin Pop | |
1252 | c71a1a3d | Iustin Pop | This is useful if you need to follow a job's progress from multiple |
1253 | c71a1a3d | Iustin Pop | terminals. |
1254 | c71a1a3d | Iustin Pop | |
1255 | c71a1a3d | Iustin Pop | A job that has not yet started to run can be canceled:: |
1256 | c71a1a3d | Iustin Pop | |
1257 | c71a1a3d | Iustin Pop | node1# gnt-job cancel 17810 |
1258 | c71a1a3d | Iustin Pop | |
1259 | c71a1a3d | Iustin Pop | But not one that has already started execution:: |
1260 | c71a1a3d | Iustin Pop | |
1261 | c71a1a3d | Iustin Pop | node1# gnt-job cancel 17805 |
1262 | c71a1a3d | Iustin Pop | Job 17805 is no longer waiting in the queue |
1263 | c71a1a3d | Iustin Pop | |
1264 | c71a1a3d | Iustin Pop | There are two queues for jobs: the *current* and the *archive* |
1265 | c71a1a3d | Iustin Pop | queue. Jobs are initially submitted to the current queue, and they stay |
1266 | c71a1a3d | Iustin Pop | in that queue until they have finished execution (either successfully or |
1267 | c71a1a3d | Iustin Pop | not). At that point, they can be moved into the archive queue, and the |
1268 | c71a1a3d | Iustin Pop | ganeti-watcher script will do this automatically after 6 hours. The |
1269 | c71a1a3d | Iustin Pop | ganeti-cleaner script will remove the jobs from the archive directory |
1270 | c71a1a3d | Iustin Pop | after three weeks. |
1271 | c71a1a3d | Iustin Pop | |
1272 | c71a1a3d | Iustin Pop | Note that only jobs in the current queue can be viewed via the list and |
1273 | c71a1a3d | Iustin Pop | info commands; Ganeti itself doesn't examine the archive directory. If |
1274 | c71a1a3d | Iustin Pop | you need to see an older job, either move the file manually in the |
1275 | c71a1a3d | Iustin Pop | top-level queue directory, or look at its contents (it's a |
1276 | c71a1a3d | Iustin Pop | JSON-formatted file). |
1277 | c71a1a3d | Iustin Pop | |
1278 | c71a1a3d | Iustin Pop | Ganeti tools |
1279 | c71a1a3d | Iustin Pop | ------------ |
1280 | c71a1a3d | Iustin Pop | |
1281 | c71a1a3d | Iustin Pop | Beside the usual ``gnt-`` and ``ganeti-`` commands which are provided |
1282 | c71a1a3d | Iustin Pop | and installed in ``$prefix/sbin`` at install time, there are a couple of |
1283 | c71a1a3d | Iustin Pop | other tools installed which are used seldom but can be helpful in some |
1284 | c71a1a3d | Iustin Pop | cases. |
1285 | c71a1a3d | Iustin Pop | |
1286 | c71a1a3d | Iustin Pop | lvmstrap |
1287 | c71a1a3d | Iustin Pop | ++++++++ |
1288 | c71a1a3d | Iustin Pop | |
1289 | c71a1a3d | Iustin Pop | The ``lvmstrap`` tool, introduced in :ref:`configure-lvm-label` section, |
1290 | c71a1a3d | Iustin Pop | has two modes of operation: |
1291 | c71a1a3d | Iustin Pop | |
1292 | c71a1a3d | Iustin Pop | - ``diskinfo`` shows the discovered disks on the system and their status |
1293 | c71a1a3d | Iustin Pop | - ``create`` takes all not-in-use disks and creates a volume group out |
1294 | c71a1a3d | Iustin Pop | of them |
1295 | c71a1a3d | Iustin Pop | |
1296 | c71a1a3d | Iustin Pop | .. warning:: The ``create`` argument to this command causes data-loss! |
1297 | c71a1a3d | Iustin Pop | |
1298 | c71a1a3d | Iustin Pop | cfgupgrade |
1299 | c71a1a3d | Iustin Pop | ++++++++++ |
1300 | c71a1a3d | Iustin Pop | |
1301 | c71a1a3d | Iustin Pop | The ``cfgupgrade`` tools is used to upgrade between major (and minor) |
1302 | c71a1a3d | Iustin Pop | Ganeti versions. Point-releases are usually transparent for the admin. |
1303 | c71a1a3d | Iustin Pop | |
1304 | c71a1a3d | Iustin Pop | More information about the upgrade procedure is listed on the wiki at |
1305 | c71a1a3d | Iustin Pop | http://code.google.com/p/ganeti/wiki/UpgradeNotes. |
1306 | c71a1a3d | Iustin Pop | |
1307 | c71a1a3d | Iustin Pop | cfgshell |
1308 | c71a1a3d | Iustin Pop | ++++++++ |
1309 | c71a1a3d | Iustin Pop | |
1310 | c71a1a3d | Iustin Pop | .. note:: This command is not actively maintained; make sure you backup |
1311 | c71a1a3d | Iustin Pop | your configuration before using it |
1312 | c71a1a3d | Iustin Pop | |
1313 | c71a1a3d | Iustin Pop | This can be used as an alternative to direct editing of the |
1314 | c71a1a3d | Iustin Pop | main configuration file if Ganeti has a bug and prevents you, for |
1315 | c71a1a3d | Iustin Pop | example, from removing an instance or a node from the configuration |
1316 | c71a1a3d | Iustin Pop | file. |
1317 | c71a1a3d | Iustin Pop | |
1318 | c71a1a3d | Iustin Pop | .. _burnin-label: |
1319 | c71a1a3d | Iustin Pop | |
1320 | c71a1a3d | Iustin Pop | burnin |
1321 | c71a1a3d | Iustin Pop | ++++++ |
1322 | c71a1a3d | Iustin Pop | |
1323 | c71a1a3d | Iustin Pop | .. warning:: This command will erase existing instances if given as |
1324 | c71a1a3d | Iustin Pop | arguments! |
1325 | c71a1a3d | Iustin Pop | |
1326 | c71a1a3d | Iustin Pop | This tool is used to exercise either the hardware of machines or |
1327 | c71a1a3d | Iustin Pop | alternatively the Ganeti software. It is safe to run on an existing |
1328 | c71a1a3d | Iustin Pop | cluster **as long as you don't pass it existing instance names**. |
1329 | c71a1a3d | Iustin Pop | |
1330 | c71a1a3d | Iustin Pop | The command will, by default, execute a comprehensive set of operations |
1331 | c71a1a3d | Iustin Pop | against a list of instances, these being: |
1332 | c71a1a3d | Iustin Pop | |
1333 | c71a1a3d | Iustin Pop | - creation |
1334 | c71a1a3d | Iustin Pop | - disk replacement (for redundant instances) |
1335 | c71a1a3d | Iustin Pop | - failover and migration (for redundant instances) |
1336 | c71a1a3d | Iustin Pop | - move (for non-redundant instances) |
1337 | c71a1a3d | Iustin Pop | - disk growth |
1338 | c71a1a3d | Iustin Pop | - add disks, remove disk |
1339 | c71a1a3d | Iustin Pop | - add NICs, remove NICs |
1340 | c71a1a3d | Iustin Pop | - export and then import |
1341 | c71a1a3d | Iustin Pop | - rename |
1342 | c71a1a3d | Iustin Pop | - reboot |
1343 | c71a1a3d | Iustin Pop | - shutdown/startup |
1344 | c71a1a3d | Iustin Pop | - and finally removal of the test instances |
1345 | c71a1a3d | Iustin Pop | |
1346 | c71a1a3d | Iustin Pop | Executing all these operations will test that the hardware performs |
1347 | c71a1a3d | Iustin Pop | well: the creation, disk replace, disk add and disk growth will exercise |
1348 | c71a1a3d | Iustin Pop | the storage and network; the migrate command will test the memory of the |
1349 | c71a1a3d | Iustin Pop | systems. Depending on the passed options, it can also test that the |
1350 | c71a1a3d | Iustin Pop | instance OS definitions are executing properly the rename, import and |
1351 | c71a1a3d | Iustin Pop | export operations. |
1352 | c71a1a3d | Iustin Pop | |
1353 | c71a1a3d | Iustin Pop | Other Ganeti projects |
1354 | c71a1a3d | Iustin Pop | --------------------- |
1355 | c71a1a3d | Iustin Pop | |
1356 | c71a1a3d | Iustin Pop | There are two other Ganeti-related projects that can be useful in a |
1357 | c71a1a3d | Iustin Pop | Ganeti deployment. These can be downloaded from the project site |
1358 | c71a1a3d | Iustin Pop | (http://code.google.com/p/ganeti/) and the repositories are also on the |
1359 | c71a1a3d | Iustin Pop | project git site (http://git.ganeti.org). |
1360 | c71a1a3d | Iustin Pop | |
1361 | c71a1a3d | Iustin Pop | NBMA tools |
1362 | c71a1a3d | Iustin Pop | ++++++++++ |
1363 | c71a1a3d | Iustin Pop | |
1364 | c71a1a3d | Iustin Pop | The ``ganeti-nbma`` software is designed to allow instances to live on a |
1365 | c71a1a3d | Iustin Pop | separate, virtual network from the nodes, and in an environment where |
1366 | c71a1a3d | Iustin Pop | nodes are not guaranteed to be able to reach each other via multicasting |
1367 | c71a1a3d | Iustin Pop | or broadcasting. For more information see the README in the source |
1368 | c71a1a3d | Iustin Pop | archive. |
1369 | c71a1a3d | Iustin Pop | |
1370 | c71a1a3d | Iustin Pop | ganeti-htools |
1371 | c71a1a3d | Iustin Pop | +++++++++++++ |
1372 | c71a1a3d | Iustin Pop | |
1373 | c71a1a3d | Iustin Pop | The ``ganeti-htools`` software consists of a set of tools: |
1374 | c71a1a3d | Iustin Pop | |
1375 | c71a1a3d | Iustin Pop | - ``hail``: an advanced iallocator script compared to Ganeti's builtin |
1376 | c71a1a3d | Iustin Pop | one |
1377 | c71a1a3d | Iustin Pop | - ``hbal``: a tool for rebalancing the cluster, i.e. moving instances |
1378 | c71a1a3d | Iustin Pop | around in order to better use the resources on the nodes |
1379 | c71a1a3d | Iustin Pop | - ``hspace``: a tool for estimating the available capacity of a cluster, |
1380 | c71a1a3d | Iustin Pop | so that capacity planning can be done efficiently |
1381 | c71a1a3d | Iustin Pop | |
1382 | c71a1a3d | Iustin Pop | For more information and installation instructions, see the README file |
1383 | c71a1a3d | Iustin Pop | in the source archive. |
1384 | c71a1a3d | Iustin Pop | |
1385 | 558fd122 | Michael Hanselmann | .. vim: set textwidth=72 : |
1386 | c71a1a3d | Iustin Pop | .. Local Variables: |
1387 | c71a1a3d | Iustin Pop | .. mode: rst |
1388 | c71a1a3d | Iustin Pop | .. fill-column: 72 |
1389 | c71a1a3d | Iustin Pop | .. End: |