1 ganeti(7) Ganeti | Version @GANETI_VERSION@
2 ===========================================
7 ganeti - cluster-based virtualization management
14 # gnt-cluster init cluster1.example.com
15 # gnt-node add node2.example.com
16 # gnt-instance add -n node2.example.com \
17 > -o debootstrap --disk 0:size=30g \
18 > -t plain instance1.example.com
24 The Ganeti software manages physical nodes and virtual instances of a
25 cluster based on a virtualization software. The current version (2.3)
26 supports Xen 3.x and KVM (72 or above) as hypervisors, and LXC as an
27 experimental hypervisor.
32 First you must install the software on all the cluster nodes, either
33 from sources or (if available) from a package. The next step is to
34 create the initial cluster configuration, using **gnt-cluster init**.
36 Then you can add other nodes, or start creating instances.
41 In Ganeti 2.0, the architecture of the cluster is a little more
42 complicated than in 1.2. The cluster is coordinated by a master daemon
43 (**ganeti-masterd**(8)), running on the master node. Each node runs
44 (as before) a node daemon, and the master has the RAPI daemon running
50 Each node can be in one of the following states:
53 Only one node per cluster can be in this role, and this node is the
54 one holding the authoritative copy of the cluster configuration and
55 the one that can actually execute commands on the cluster and
56 modify the cluster state. See more details under
57 *Cluster configuration*.
60 The node receives the full cluster configuration (configuration
61 file and jobs) and can become a master via the
62 **gnt-cluster master-failover** command. Nodes that are not in this
63 state cannot transition into the master role due to missing state.
66 This the normal state of a node.
69 Nodes in this state are functioning normally but cannot receive
70 new instances, because the intention is to set them to *offline*
71 or remove them from the cluster.
74 These nodes are still recorded in the Ganeti configuration, but
75 except for the master daemon startup voting procedure, they are not
76 actually contacted by the master. This state was added in order to
77 allow broken machines (that are being repaired) to remain in the
78 cluster but without creating problems.
84 Nodes have two flags which govern which roles they can take:
87 The node can become a master candidate, and furthermore the master
88 node. When this flag is disabled, the node cannot become a
89 candidate; this can be useful for special networking cases, or less
93 The node can host instances. When enabled (the default state), the
94 node will participate in instance allocation, capacity calculation,
95 etc. When disabled, the node will be skipped in many cluster checks
102 The ``ndparams`` refer to node parameters. These can be set as defaults
103 on cluster and node group levels, but they take effect for nodes only.
105 Currently we support the following node parameters:
108 Path to an executable used as the out-of-band helper as described in
109 the `Ganeti Node OOB Management Framework <design-oob.rst>`_ design
113 This should reflect the I/O performance of local attached storage
114 (e.g. for "file", "plain" and "drbd" disk templates). It doesn't
115 have to match the actual spindle count of (any eventual) mechanical
116 hard-drives, its meaning is site-local and just the relative values
120 Hypervisor State Parameters
121 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
123 Using ``--hypervisor-state`` you can set hypervisor specific states as
124 pointed out in ``Ganeti Resource Model <design-resource-model.rst>``.
126 The format is: ``hypervisor:option=value``.
128 Currently we support the following hypervisor state values:
131 Total node memory, as discovered by this hypervisor
133 Memory used by, or reserved for, the node itself; note that some
134 hypervisors can report this in an authoritative way, other not
136 Memory used either by the hypervisor itself or lost due to instance
137 allocation rounding; usually this cannot be precisely computed, but
138 only roughly estimated
140 Total node cpu (core) count; usually this can be discovered
143 Number of cores reserved for the node itself; this can either be
144 discovered or set manually. Only used for estimating how many VCPUs
145 are left for instances
148 Disk State Parameters
149 ~~~~~~~~~~~~~~~~~~~~~
151 Using ``--disk-state`` you can set disk specific states as pointed out
152 in ``Ganeti Resource Model <design-resource-model.rst>``.
154 The format is: ``storage_type/identifier:option=value``. Where we
155 currently just support ``lvm`` as storage type. The identifier in this
156 case is the LVM volume group. By default this is ``xenvg``.
158 Currently we support the following hypervisor state values:
161 Total disk size (usually discovered automatically)
163 Reserved disk size; this is a lower limit on the free space, if such a
166 Disk that is expected to be used by other volumes (set via
167 ``reserved_lvs``); usually should be zero
170 Cluster configuration
171 ~~~~~~~~~~~~~~~~~~~~~
173 The master node keeps and is responsible for the cluster
174 configuration. On the filesystem, this is stored under the
175 ``@LOCALSTATEDIR@/ganeti/lib`` directory, and if the master daemon is
176 stopped it can be backed up normally.
178 The master daemon will replicate the configuration database called
179 ``config.data`` and the job files to all the nodes in the master
180 candidate role. It will also distribute a copy of some configuration
181 values via the *ssconf* files, which are stored in the same directory
182 and start with a ``ssconf_`` prefix, to all nodes.
187 All cluster modification are done via jobs. A job consists of one
188 or more opcodes, and the list of opcodes is processed serially. If
189 an opcode fails, the entire job is failed and later opcodes are no
190 longer processed. A job can be in one of the following states:
193 The job has been submitted but not yet processed by the master
197 The job is waiting for for locks before the first of its opcodes.
200 The job is waiting for locks, but is has been marked for
201 cancellation. It will not transition to *running*, but to
205 The job is currently being executed.
208 The job has been canceled before starting execution.
211 The job has finished successfully.
214 The job has failed during runtime, or the master daemon has been
215 stopped during the job execution.
218 Common command line features
219 ----------------------------
224 Many Ganeti commands provide the following options. The
225 availability for a certain command can be checked by calling the
226 command using the ``--help`` option.
228 | **gnt-...** *command* [\--dry-run] [\--priority {low | normal | high}]
231 The ``--dry-run`` option can be used to check whether an operation
234 The option ``--priority`` sets the priority for opcodes submitted
237 The ``--submit`` option is used to send the job to the master daemon but
238 not wait for its completion. The job ID will be shown so that it can be
239 examined using **gnt-job info**.
244 For certain commands you can use environment variables to provide
245 default command line arguments. Just assign the arguments as a string to
246 the corresponding environment variable. The format of that variable
247 name is **binary**_*command*. **binary** is the name of the ``gnt-*``
248 script all upper case and dashes replaced by underscores, and *command*
249 is the command invoked on that script.
251 Currently supported commands are ``gnt-node list``, ``gnt-group list``
252 and ``gnt-instance list``. So you can configure default command line
253 flags by setting ``GNT_NODE_LIST``, ``GNT_GROUP_LIST`` and
254 ``GNT_INSTANCE_LIST``.
259 Multiple ganeti commands use the same framework for tabular listing of
260 resources (e.g. **gnt-instance list**, **gnt-node list**, **gnt-group
261 list**, **gnt-debug locks**, etc.). For these commands, special states
262 are denoted via a special symbol (in terse mode) or a string (in
266 The node in question is marked offline, and thus it cannot be
267 queried for data. This result is persistent until the node is
271 Ganeti expected to receive an answer from this entity, but the
272 cluster RPC call failed and/or we didn't receive a valid answer;
273 usually more information is available in the node daemon log (if
274 the node is alive) or the master daemon log. This result is
275 transient, and re-running command might return a different result.
278 The respective field doesn't make sense for this entity;
279 e.g. querying a down instance for its current memory 'live' usage,
280 or querying a non-vm_capable node for disk/memory data. This
281 result is persistent, and until the entity state is changed via
282 ganeti commands, the result won't change.
285 This field is not known (note that this is different from entity
286 being unknown). Either you have mis-typed the field name, or you
287 are using a field that the running Ganeti master daemon doesn't
288 know. This result is persistent, re-running the command won't
294 Multiple options take parameters that are of the form
295 ``key=value,key=value,...`` or ``category:key=value,...``. Examples
296 are the hypervisor parameters, backend parameters, etc. For these,
297 it's possible to use values that contain commas by escaping with via a
298 backslash (which needs two if not single-quoted, due to shell
301 # gnt-instance modify -H kernel_path=an\\,example instance1
302 # gnt-instance modify -H kernel_path='an\,example' instance1
307 Most commands listing resources (e.g. instances or nodes) support filtering.
308 The filter language is similar to Python expressions with some elements from
309 Perl. The language is not generic. Each condition must consist of a field name
310 and a value (except for boolean checks), a field can not be compared to another
311 field. Keywords are case-sensitive.
313 Examples (see below for syntax details):
317 gnt-instance list --filter 'name =* "web*.example.com"'
319 - List instances with three or six virtual CPUs and whose primary
320 nodes reside in groups starting with the string "rack"::
322 gnt-instance list --filter
323 '(be/vcpus == 3 or be/vcpus == 6) and pnode.group =~ m/^rack/'
325 - Nodes hosting primary instances::
327 gnt-node list --filter 'pinst_cnt != 0'
329 - Nodes which aren't master candidates::
331 gnt-node list --filter 'not master_candidate'
333 - Short version for globbing patterns::
335 gnt-instance list '*.site1' '*.site2'
337 Syntax in pseudo-BNF::
339 <quoted-string> ::= /* String quoted with single or double quotes,
340 backslash for escaping */
342 <integer> ::= /* Number in base-10 positional notation */
344 <re> ::= /* Regular expression */
347 Modifier "i": Case-insensitive matching, see
348 http://docs.python.org/library/re#re.IGNORECASE
350 Modifier "s": Make the "." special character match any character,
351 including newline, see http://docs.python.org/library/re#re.DOTALL
353 <re-modifiers> ::= /* empty */ | i | s
355 <value> ::= <quoted-string> | <integer>
358 { /* Value comparison */
359 <field> { == | != } <value>
361 /* Collection membership */
362 | <value> [ not ] in <field>
364 /* Regular expressions (recognized delimiters
365 are "/", "#", "^", and "|"; backslash for escaping)
367 | <field> { =~ | !~ } m/<re>/<re-modifiers>
370 | <field> { =* | !* } <quoted-string>
377 { [ not ] <condition> | ( <filter> ) }
378 [ { and | or } <filter> ]
387 Pattern match using regular expression
389 Logically negated from *=~*
391 Globbing, see **glob**(7), though only * and ? are supported
393 Logically negated from *=\**
395 Collection membership and negation
398 Common daemon functionality
399 ---------------------------
401 All Ganeti daemons re-open the log file(s) when sent a SIGHUP signal.
402 **logrotate**(8) can be used to rotate Ganeti's log files.
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