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1 | 4db3647e | Iustin Pop | ganeti-os-interface(7) Ganeti | Version @GANETI_VERSION@ |
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2 | 4db3647e | Iustin Pop | ======================================================== |
3 | 4db3647e | Iustin Pop | |
4 | 4db3647e | Iustin Pop | Name |
5 | 4db3647e | Iustin Pop | ---- |
6 | 4db3647e | Iustin Pop | |
7 | 4db3647e | Iustin Pop | ganeti-os-interface - Specifications for guest OS types |
8 | 4db3647e | Iustin Pop | |
9 | 4db3647e | Iustin Pop | DESCRIPTION |
10 | 4db3647e | Iustin Pop | ----------- |
11 | 4db3647e | Iustin Pop | |
12 | 4db3647e | Iustin Pop | The method of supporting guest operating systems in Ganeti is to |
13 | 4db3647e | Iustin Pop | have, for each guest OS type, a directory containing a number of |
14 | 4db3647e | Iustin Pop | required files. |
15 | 4db3647e | Iustin Pop | |
16 | 4db3647e | Iustin Pop | REFERENCE |
17 | 4db3647e | Iustin Pop | --------- |
18 | 4db3647e | Iustin Pop | |
19 | 4db3647e | Iustin Pop | There are six required files: *create*, *import*, *export*, *rename* |
20 | 4db3647e | Iustin Pop | (executables), *ganeti_api_version* and *variants.list* (text files). |
21 | 4db3647e | Iustin Pop | |
22 | 4db3647e | Iustin Pop | Common environment |
23 | 4db3647e | Iustin Pop | ~~~~~~~~~~~~~~~~~~ |
24 | 4db3647e | Iustin Pop | |
25 | 4db3647e | Iustin Pop | All commands will get their input via environment variables. A |
26 | 4db3647e | Iustin Pop | common set of variables will be exported for all commands, and some |
27 | 4db3647e | Iustin Pop | of them might have extra ones. Note that all counts are |
28 | 4db3647e | Iustin Pop | zero-based. |
29 | 4db3647e | Iustin Pop | |
30 | 4db3647e | Iustin Pop | |
31 | 4db3647e | Iustin Pop | |
32 | 4db3647e | Iustin Pop | OS_API_VERSION |
33 | 4db3647e | Iustin Pop | The OS API version that the rest of the environment conforms to. |
34 | 4db3647e | Iustin Pop | |
35 | 4db3647e | Iustin Pop | INSTANCE_NAME |
36 | 4db3647e | Iustin Pop | The instance name the script should operate on. |
37 | 4db3647e | Iustin Pop | |
38 | 4db3647e | Iustin Pop | INSTANCE_OS, OS_NAME |
39 | 4db3647e | Iustin Pop | Both names point to the name of the instance's OS as Ganeti knows |
40 | 4db3647e | Iustin Pop | it. This can simplify the OS scripts by providing the same scripts |
41 | 4db3647e | Iustin Pop | under multiple names, and then the scripts can use this name to |
42 | 4db3647e | Iustin Pop | alter their behaviour. |
43 | 4db3647e | Iustin Pop | |
44 | 4db3647e | Iustin Pop | With OS API 15 changing the script behavior based on this variable |
45 | 4db3647e | Iustin Pop | is deprecated: OS_VARIANT should be used instead (see below). |
46 | 4db3647e | Iustin Pop | |
47 | 4db3647e | Iustin Pop | OS_VARIANT |
48 | 4db3647e | Iustin Pop | The variant of the OS which should be installed. Each OS must |
49 | 4db3647e | Iustin Pop | support all variants listed under its variants.list file, and may |
50 | 4db3647e | Iustin Pop | support more. Any more supported variants should be properly |
51 | 4db3647e | Iustin Pop | documented in the per-OS documentation. |
52 | 4db3647e | Iustin Pop | |
53 | 4db3647e | Iustin Pop | HYPERVISOR |
54 | 4db3647e | Iustin Pop | The hypervisor of this instance. |
55 | 4db3647e | Iustin Pop | |
56 | 4db3647e | Iustin Pop | DISK_COUNT |
57 | 4db3647e | Iustin Pop | The number of disks the instance has. The actual disk defitions are |
58 | 4db3647e | Iustin Pop | in a set of additional variables. The instance's disk will be |
59 | 4db3647e | Iustin Pop | numbered from 0 to this value minus one. |
60 | 4db3647e | Iustin Pop | |
61 | 4db3647e | Iustin Pop | DISK_%N_PATH |
62 | 4db3647e | Iustin Pop | The path to the storage for disk N of the instance. This might be |
63 | 4db3647e | Iustin Pop | either a block device or a regular file, in which case the OS |
64 | 4db3647e | Iustin Pop | scripts should use ``losetup`` (if they need to mount it). E.g. the |
65 | 4db3647e | Iustin Pop | first disk of the instance might be exported as |
66 | 4db3647e | Iustin Pop | ``DISK_0_PATH=/dev/drbd0``. |
67 | 4db3647e | Iustin Pop | |
68 | 4db3647e | Iustin Pop | DISK_%N_ACCESS |
69 | 4db3647e | Iustin Pop | This is how the hypervisor will export the instance disks: either |
70 | 4db3647e | Iustin Pop | read-write (``rw``) or read-only (``ro``). |
71 | 4db3647e | Iustin Pop | |
72 | 4db3647e | Iustin Pop | DISK_%N_FRONTEND_TYPE |
73 | 4db3647e | Iustin Pop | (Optional) If applicable to the current hypervisor type: the type |
74 | 4db3647e | Iustin Pop | of the device exported by the hypervisor. For example, the Xen HVM |
75 | 4db3647e | Iustin Pop | hypervisor can export disks as either ``paravirtual`` or |
76 | 4db3647e | Iustin Pop | ``ioemu``. |
77 | 4db3647e | Iustin Pop | |
78 | 4db3647e | Iustin Pop | DISK_%N_BACKEND_TYPE |
79 | 4db3647e | Iustin Pop | How files are visible on the node side. This can be either |
80 | 4db3647e | Iustin Pop | ``block`` (when using block devices) or ``file:type``, where |
81 | 4db3647e | Iustin Pop | ``type`` is either ``loop`` or ``blktap`` depending on how the |
82 | 4db3647e | Iustin Pop | hypervisor will be configured. Note that not all backend types |
83 | 4db3647e | Iustin Pop | apply to all hypervisors. |
84 | 4db3647e | Iustin Pop | |
85 | 4db3647e | Iustin Pop | NIC_COUNT |
86 | 4db3647e | Iustin Pop | Similar to the ``DISK_COUNT``, this represents the number of NICs |
87 | 4db3647e | Iustin Pop | of the instance. |
88 | 4db3647e | Iustin Pop | |
89 | 4db3647e | Iustin Pop | NIC_%N_MAC |
90 | 4db3647e | Iustin Pop | The MAC address associated with this interface. |
91 | 4db3647e | Iustin Pop | |
92 | 4db3647e | Iustin Pop | NIC_%N_IP |
93 | 4db3647e | Iustin Pop | The IP address, if any, associated with the N-th NIC of the |
94 | 4db3647e | Iustin Pop | instance. |
95 | 4db3647e | Iustin Pop | |
96 | 4db3647e | Iustin Pop | NIC_%N_MODE |
97 | 4db3647e | Iustin Pop | The NIC mode, either routed or bridged |
98 | 4db3647e | Iustin Pop | |
99 | 4db3647e | Iustin Pop | NIC_%N_BRIDGE |
100 | 4db3647e | Iustin Pop | The bridge to which this NIC will be attached. This variable is |
101 | 4db3647e | Iustin Pop | defined only when the NIC is in bridged mode. |
102 | 4db3647e | Iustin Pop | |
103 | 4db3647e | Iustin Pop | NIC_%N_LINK |
104 | 4db3647e | Iustin Pop | If the NIC is in bridged mode, this is the same as |
105 | 4db3647e | Iustin Pop | ``NIC_%N_BRIDGE``. If it is in routed mode, the routing table |
106 | 4db3647e | Iustin Pop | which will be used by the hypervisor to insert the appropriate |
107 | 4db3647e | Iustin Pop | routes. |
108 | 4db3647e | Iustin Pop | |
109 | 4db3647e | Iustin Pop | NIC_%N_FRONTEND_TYPE |
110 | 4db3647e | Iustin Pop | (Optional) If applicable, the type of the exported NIC to the |
111 | 4db3647e | Iustin Pop | instance, this can be one of: ``rtl8139``, ``ne2k_pci``, |
112 | 4db3647e | Iustin Pop | ``ne2k_isa``, ``paravirtual``. |
113 | 4db3647e | Iustin Pop | |
114 | 4db3647e | Iustin Pop | DEBUG_LEVEL |
115 | 4db3647e | Iustin Pop | If non-zero, this should cause the OS script to generate verbose |
116 | 4db3647e | Iustin Pop | logs of its execution, for troubleshooting purposes. Currently |
117 | 4db3647e | Iustin Pop | only ``0`` and ``1`` are valid values. |
118 | 4db3647e | Iustin Pop | |
119 | 4db3647e | Iustin Pop | |
120 | 4db3647e | Iustin Pop | create |
121 | 4db3647e | Iustin Pop | ~~~~~~ |
122 | 4db3647e | Iustin Pop | |
123 | 4db3647e | Iustin Pop | The **create** command is used for creating a new instance from |
124 | 4db3647e | Iustin Pop | scratch. It has no additional environment variables bside the |
125 | 4db3647e | Iustin Pop | common ones. |
126 | 4db3647e | Iustin Pop | |
127 | 4db3647e | Iustin Pop | The ``INSTANCE_NAME`` variable denotes the name of the instance, |
128 | 4db3647e | Iustin Pop | which is guaranteed to resolve to an IP address. The create script |
129 | 4db3647e | Iustin Pop | should configure the instance according to this name. It can |
130 | 4db3647e | Iustin Pop | configure the IP statically or not, depending on the deployment |
131 | 4db3647e | Iustin Pop | environment. |
132 | 4db3647e | Iustin Pop | |
133 | 4db3647e | Iustin Pop | The ``INSTANCE_REINSTALL`` variable is set to ``1`` when this create |
134 | 4db3647e | Iustin Pop | request is reinstalling and existing instance, rather than creating |
135 | 4db3647e | Iustin Pop | one anew. This can be used, for example, to preserve some data in the |
136 | 4db3647e | Iustin Pop | old instance in an OS-specific way. |
137 | 4db3647e | Iustin Pop | |
138 | 4db3647e | Iustin Pop | export |
139 | 4db3647e | Iustin Pop | ~~~~~~ |
140 | 4db3647e | Iustin Pop | |
141 | 4db3647e | Iustin Pop | This command is used in order to make a backup of a given disk of |
142 | 4db3647e | Iustin Pop | the instance. The command should write to stdout a dump of the |
143 | 4db3647e | Iustin Pop | given block device. The output of this program will be passed |
144 | 4db3647e | Iustin Pop | during restore to the **import** command. |
145 | 4db3647e | Iustin Pop | |
146 | 4db3647e | Iustin Pop | The specific disk to backup is denoted by two additional environment |
147 | 4db3647e | Iustin Pop | variables: ``EXPORT_INDEX`` which denotes the index in the instance |
148 | 4db3647e | Iustin Pop | disks structure (and could be used for example to skip the second disk |
149 | 4db3647e | Iustin Pop | if not needed for backup) and ``EXPORT_PATH`` which has the same value |
150 | 4db3647e | Iustin Pop | as ``DISK_N_PATH`` but is duplicate here for easier usage by shell |
151 | 4db3647e | Iustin Pop | scripts (rather than parse the ``DISK_...`` variables). |
152 | 4db3647e | Iustin Pop | |
153 | 4db3647e | Iustin Pop | To provide the user with an estimate on how long the export will take, |
154 | 4db3647e | Iustin Pop | a predicted size can be written to the file descriptor passed in the |
155 | 4db3647e | Iustin Pop | variable ``EXP_SIZE_FD``. The value is in bytes and must be terminated |
156 | 4db3647e | Iustin Pop | by a newline character (``\n``). Older versions of Ganeti don't |
157 | 4db3647e | Iustin Pop | support this feature, hence the variable should be checked before |
158 | 4db3647e | Iustin Pop | use. Example:: |
159 | 4db3647e | Iustin Pop | |
160 | 4db3647e | Iustin Pop | if test -n "$EXP_SIZE_FD"; then |
161 | 4db3647e | Iustin Pop | blockdev --getsize64 $blockdev >&$EXP_SIZE_FD |
162 | 4db3647e | Iustin Pop | fi |
163 | 4db3647e | Iustin Pop | |
164 | 4db3647e | Iustin Pop | import |
165 | 4db3647e | Iustin Pop | ~~~~~~ |
166 | 4db3647e | Iustin Pop | |
167 | 4db3647e | Iustin Pop | The **import** command is used for restoring an instance from a |
168 | 4db3647e | Iustin Pop | backup as done by **export**. The arguments are the similar to |
169 | 4db3647e | Iustin Pop | those passed to **export**, whose output will be provided on |
170 | 4db3647e | Iustin Pop | stdin. |
171 | 4db3647e | Iustin Pop | |
172 | 4db3647e | Iustin Pop | The difference in variables is that the current disk is called by |
173 | 4db3647e | Iustin Pop | ``IMPORT_DEVICE`` and ``IMPORT_INDEX`` (instead of ``EXPORT_...``). |
174 | 4db3647e | Iustin Pop | |
175 | 4db3647e | Iustin Pop | rename |
176 | 4db3647e | Iustin Pop | ~~~~~~ |
177 | 4db3647e | Iustin Pop | |
178 | 4db3647e | Iustin Pop | This command is used in order to perform a rename at the instance |
179 | 4db3647e | Iustin Pop | OS level, after the instance has been renamed in Ganeti. The |
180 | 4db3647e | Iustin Pop | command should do whatever steps are required to ensure that the |
181 | 4db3647e | Iustin Pop | instance is updated to use the new name, if the operating system |
182 | 4db3647e | Iustin Pop | supports it. |
183 | 4db3647e | Iustin Pop | |
184 | 4db3647e | Iustin Pop | Note that it is acceptable for the rename script to do nothing at |
185 | 4db3647e | Iustin Pop | all, however be warned that in this case, there will be a |
186 | 4db3647e | Iustin Pop | desynchronization between what gnt-instance list shows you and the |
187 | 4db3647e | Iustin Pop | actual hostname of the instance. |
188 | 4db3647e | Iustin Pop | |
189 | 4db3647e | Iustin Pop | The script will be passed one additional environment variable |
190 | 4db3647e | Iustin Pop | called ``OLD_INSTANCE_NAME`` which holds the old instance name. The |
191 | 4db3647e | Iustin Pop | ``INSTANCE_NAME`` variable holds the new instance name. |
192 | 4db3647e | Iustin Pop | |
193 | 4db3647e | Iustin Pop | A very simple rename script should at least change the hostname and |
194 | 4db3647e | Iustin Pop | IP address of the instance, leaving the administrator to update the |
195 | 4db3647e | Iustin Pop | other services. |
196 | 4db3647e | Iustin Pop | |
197 | 4db3647e | Iustin Pop | ganeti_api_version |
198 | 4db3647e | Iustin Pop | ~~~~~~~~~~~~~~~~~~ |
199 | 4db3647e | Iustin Pop | |
200 | 4db3647e | Iustin Pop | The ganeti_api_version file is a plain text file containing the |
201 | 4db3647e | Iustin Pop | version(s) of the guest OS API that this OS definition complies |
202 | 4db3647e | Iustin Pop | with, one per line. The version documented by this man page is 15, |
203 | 4db3647e | Iustin Pop | so this file must contain the number 15 followed by a newline if |
204 | 4db3647e | Iustin Pop | only this version is supported. A script compatible with more than |
205 | 4db3647e | Iustin Pop | one Ganeti version should contain the most recent version first |
206 | 4db3647e | Iustin Pop | (i.e. 15), followed by the old version(s) (in this case 10 and/or |
207 | 4db3647e | Iustin Pop | 5). |
208 | 4db3647e | Iustin Pop | |
209 | 4db3647e | Iustin Pop | variants.list |
210 | 4db3647e | Iustin Pop | ~~~~~~~~~~~~~ |
211 | 4db3647e | Iustin Pop | |
212 | 4db3647e | Iustin Pop | variants.list is a plain text file containing all the declared |
213 | 4db3647e | Iustin Pop | supported variants for this OS, one per line. At least one variant |
214 | 4db3647e | Iustin Pop | must be supported. |
215 | 4db3647e | Iustin Pop | |
216 | 4db3647e | Iustin Pop | NOTES |
217 | 4db3647e | Iustin Pop | ----- |
218 | 4db3647e | Iustin Pop | |
219 | 4db3647e | Iustin Pop | Backwards compatibility |
220 | 4db3647e | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~ |
221 | 4db3647e | Iustin Pop | |
222 | 4db3647e | Iustin Pop | Ganeti 2.2 is compatible with both API version 10, and 15. In API |
223 | 4db3647e | Iustin Pop | version 10 the variants.list file is ignored and no OS_VARIANT |
224 | 4db3647e | Iustin Pop | environment variable is passed. |
225 | 4db3647e | Iustin Pop | |
226 | 4db3647e | Iustin Pop | Common behaviour |
227 | 4db3647e | Iustin Pop | ~~~~~~~~~~~~~~~~ |
228 | 4db3647e | Iustin Pop | |
229 | 4db3647e | Iustin Pop | All the scripts should display an usage message when called with a |
230 | 4db3647e | Iustin Pop | wrong number of arguments or when the first argument is ``-h`` or |
231 | 4db3647e | Iustin Pop | ``--help``. |
232 | 4db3647e | Iustin Pop | |
233 | 4db3647e | Iustin Pop | Upgrading from old versions |
234 | 4db3647e | Iustin Pop | ~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
235 | 4db3647e | Iustin Pop | |
236 | 4db3647e | Iustin Pop | Version 10 to 15 |
237 | 4db3647e | Iustin Pop | ^^^^^^^^^^^^^^^^ |
238 | 4db3647e | Iustin Pop | |
239 | 4db3647e | Iustin Pop | The ``variants.list`` file has been added, so OSes should support at |
240 | 4db3647e | Iustin Pop | least one variant, declaring it in that file and must be prepared to |
241 | 4db3647e | Iustin Pop | parse the OS_VARIANT environment variable. OSes are free to support |
242 | 4db3647e | Iustin Pop | more variants than just the declared ones. |
243 | 4db3647e | Iustin Pop | |
244 | 4db3647e | Iustin Pop | Version 5 to 10 |
245 | 4db3647e | Iustin Pop | ^^^^^^^^^^^^^^^ |
246 | 4db3647e | Iustin Pop | |
247 | 4db3647e | Iustin Pop | The method for passing data has changed from command line options |
248 | 4db3647e | Iustin Pop | to environment variables, so scripts should be modified to use |
249 | 4db3647e | Iustin Pop | these. For an example of how this can be done in a way compatible |
250 | 4db3647e | Iustin Pop | with both versions, feel free to look at the debootstrap instance's |
251 | 4db3647e | Iustin Pop | common.sh auxiliary script. |
252 | 4db3647e | Iustin Pop | |
253 | 4db3647e | Iustin Pop | Also, instances can have now a variable number of disks, not only |
254 | 4db3647e | Iustin Pop | two, and a variable number of NICs (instead of fixed one), so the |
255 | 4db3647e | Iustin Pop | scripts should deal with this. The biggest change is in the |
256 | 4db3647e | Iustin Pop | import/export, which are called once per disk, instead of once per |
257 | 4db3647e | Iustin Pop | instance. |
258 | 4db3647e | Iustin Pop | |
259 | 4db3647e | Iustin Pop | Version 4 to 5 |
260 | 4db3647e | Iustin Pop | ^^^^^^^^^^^^^^ |
261 | 4db3647e | Iustin Pop | |
262 | 4db3647e | Iustin Pop | The rename script has been added. If you don't want to do any |
263 | 4db3647e | Iustin Pop | changes on the instances after a rename, you can migrate the OS |
264 | 4db3647e | Iustin Pop | definition to version 5 by creating the rename script simply as:: |
265 | 4db3647e | Iustin Pop | |
266 | 4db3647e | Iustin Pop | #!/bin/sh |
267 | 4db3647e | Iustin Pop | |
268 | 4db3647e | Iustin Pop | exit 0 |
269 | 4db3647e | Iustin Pop | |
270 | 4db3647e | Iustin Pop | Note that the script must be executable. |