1 Ganeti customisation using hooks
2 ================================
4 Documents ganeti version 2.0
12 In order to allow customisation of operations, ganeti runs scripts
13 under ``/etc/ganeti/hooks`` based on certain rules.
16 This is similar to the ``/etc/network/`` structure present in Debian
17 for network interface handling.
22 For every operation, two sets of scripts are run:
24 - pre phase (for authorization/checking)
25 - post phase (for logging)
27 Also, for each operation, the scripts are run on one or more nodes,
28 depending on the operation type.
30 Note that, even though we call them scripts, we are actually talking
36 The *pre* scripts have a definite target: to check that the operation
37 is allowed given the site-specific constraints. You could have, for
38 example, a rule that says every new instance is required to exists in
39 a database; to implement this, you could write a script that checks
40 the new instance parameters against your database.
42 The objective of these scripts should be their return code (zero or
43 non-zero for success and failure). However, if they modify the
44 environment in any way, they should be idempotent, as failed
45 executions could be restarted and thus the script(s) run again with
46 exactly the same parameters.
48 Note that if a node is unreachable at the time a hooks is run, this
49 will not be interpreted as a deny for the execution. In other words,
50 only an actual error returned from a script will cause abort, and not
53 Therefore, if you want to guarantee that a hook script is run and
54 denies an action, it's best to put it on the master node.
59 These scripts should do whatever you need as a reaction to the
60 completion of an operation. Their return code is not checked (but
61 logged), and they should not depend on the fact that the *pre* scripts
67 The allowed names for the scripts consist of (similar to *run-parts* )
68 upper and lower case, digits, underscores and hyphens. In other words,
69 the regexp ``^[a-zA-Z0-9_-]+$``. Also, non-executable scripts will be
76 On a single node, the scripts in a directory are run in lexicographic
77 order (more exactly, the python string comparison order). It is
78 advisable to implement the usual *NN-name* convention where *NN* is a
81 For an operation whose hooks are run on multiple nodes, there is no
82 specific ordering of nodes with regard to hooks execution; you should
83 assume that the scripts are run in parallel on the target nodes
84 (keeping on each node the above specified ordering). If you need any
85 kind of inter-node synchronisation, you have to implement it yourself
91 The scripts will be run as follows:
93 - no command line arguments
95 - no controlling *tty*
97 - stdin is actually */dev/null*
99 - stdout and stderr are directed to files
101 - PATH is reset to ``/sbin:/bin:/usr/sbin:/usr/bin``
103 - the environment is cleared, and only ganeti-specific variables will
107 All information about the cluster is passed using environment
108 variables. Different operations will have sligthly different
109 environments, but most of the variables are common.
120 Adds a node to the cluster.
123 :env. vars: NODE_NAME, NODE_PIP, NODE_SIP
124 :pre-execution: all existing nodes
125 :post-execution: all nodes plus the new node
131 Removes a node from the cluster.
133 :directory: node-remove
134 :env. vars: NODE_NAME
135 :pre-execution: all existing nodes except the removed node
136 :post-execution: all existing nodes except the removed node
141 Changes a node's parameters.
143 :directory: node-modify
144 :env. vars: MASTER_CANDIDATE, OFFLINE, DRAINED
145 :pre-execution: master node, the target node
146 :post-execution: master node, the target node
151 Relocate secondary instances from a node.
153 :directory: node-evacuate
154 :env. vars: NEW_SECONDARY, NODE_NAME
155 :pre-execution: master node, target node
156 :post-execution: master node, target node
162 All instance operations take at least the following variables:
163 INSTANCE_NAME, INSTANCE_PRIMARY, INSTANCE_SECONDARIES,
164 INSTANCE_OS_TYPE, INSTANCE_DISK_TEMPLATE, INSTANCE_MEMORY,
165 INSTANCE_DISK_SIZES, INSTANCE_VCPUS, INSTANCE_NIC_COUNT,
166 INSTANCE_NICn_IP, INSTANCE_NICn_BRIDGE, INSTANCE_NICn_MAC,
167 INSTANCE_DISK_COUNT, INSTANCE_DISKn_SIZE, INSTANCE_DISKn_MODE.
169 The INSTANCE_NICn_* and INSTANCE_DISKn_* variables represent the
170 properties of the *n* -th NIC and disk, and are zero-indexed.
176 Creates a new instance.
178 :directory: instance-add
179 :env. vars: ADD_MODE, SRC_NODE, SRC_PATH, SRC_IMAGES
180 :pre-execution: master node, primary and secondary nodes
181 :post-execution: master node, primary and secondary nodes
183 OP_INSTANCE_REINSTALL
184 +++++++++++++++++++++
186 Reinstalls an instance.
188 :directory: instance-reinstall
189 :env. vars: only the standard instance vars
190 :pre-execution: master node, primary and secondary nodes
191 :post-execution: master node, primary and secondary nodes
196 Exports the instance.
199 :directory: instance-export
200 :env. vars: EXPORT_NODE, EXPORT_DO_SHUTDOWN
201 :pre-execution: master node, primary and secondary nodes
202 :post-execution: master node, primary and secondary nodes
209 :directory: instance-start
210 :env. vars: INSTANCE_NAME, INSTANCE_PRIMARY, INSTANCE_SECONDARIES, FORCE
211 :pre-execution: master node, primary and secondary nodes
212 :post-execution: master node, primary and secondary nodes
219 :directory: instance-shutdown
220 :env. vars: INSTANCE_NAME, INSTANCE_PRIMARY, INSTANCE_SECONDARIES
221 :pre-execution: master node, primary and secondary nodes
222 :post-execution: master node, primary and secondary nodes
229 :directory: instance-reboot
230 :env. vars: IGNORE_SECONDARIES, REBOOT_TYPE
231 :pre-execution: master node, primary and secondary nodes
232 :post-execution: master node, primary and secondary nodes
237 Modifies the instance parameters.
239 :directory: instance-modify
240 :env. vars: INSTANCE_NAME, MEM_SIZE, VCPUS, INSTANCE_IP
241 :pre-execution: master node, primary and secondary nodes
242 :post-execution: master node, primary and secondary nodes
247 Failovers an instance.
249 :directory: instance-failover
250 :env. vars: IGNORE_CONSISTENCY
251 :pre-execution: master node, secondary node
252 :post-execution: master node, secondary node
257 Migrates an instance.
259 :directory: instance-failover
260 :env. vars: INSTANCE_MIGRATE_LIVE, INSTANCE_MIGRATE_CLEANUP
261 :pre-execution: master node, secondary node
262 :post-execution: master node, secondary node
270 :directory: instance-remove
271 :env. vars: INSTANCE_NAME, INSTANCE_PRIMARY, INSTANCE_SECONDARIES
272 :pre-execution: master node
273 :post-execution: master node
275 OP_INSTANCE_REPLACE_DISKS
276 +++++++++++++++++++++++++
278 Replace an instance's disks.
280 :directory: mirror-replace
281 :env. vars: MODE, NEW_SECONDARY, OLD_SECONDARY
282 :pre-execution: master node, primary and secondary nodes
283 :post-execution: master node, primary and secondary nodes
285 OP_INSTANCE_GROW_DISK
286 +++++++++++++++++++++
288 Grows the disk of an instance.
290 :directory: disk-grow
291 :env. vars: DISK, AMOUNT
292 :pre-execution: master node, primary node
293 :post-execution: master node, primary node
300 :directory: instance-rename
301 :env. vars: INSTANCE_NEW_NAME
302 :pre-execution: master node, primary and secondary nodes
303 :post-execution: master node, primary and secondary nodes
311 Verifies the cluster status. This is a special LU with regard to
312 hooks, as the result of the opcode will be combined with the result of
313 post-execution hooks, in order to allow administrators to enhance the
314 cluster verification procedure.
316 :directory: cluster-verify
317 :env. vars: CLUSTER, MASTER, CLUSTER_TAGS, NODE_TAGS_<name>
319 :post-execution: all nodes
326 :directory: cluster-rename
328 :pre-execution: master-node
329 :post-execution: master-node
331 OP_CLUSTER_SET_PARAMS
332 +++++++++++++++++++++
334 Modifies the cluster parameters.
336 :directory: cluster-modify
337 :env. vars: NEW_VG_NAME
338 :pre-execution: master node
339 :post-execution: master node
345 The following operations are no longer present or don't execute hooks
346 anymore in Ganeti 2.0:
350 - OP_INSTANCE_ADD_MDDRBD
351 - OP_INSTANCE_REMOVE_MDDRBD
354 Environment variables
355 ---------------------
357 Note that all variables listed here are actually prefixed with
358 *GANETI_* in order to provide a clear namespace.
363 This is the list of environment variables supported by all operations:
366 Documents the hooks interface version. In case this doesnt match
367 what the script expects, it should not run. The documents conforms
371 One of *PRE* or *POST* denoting which phase are we in.
380 One of the *OP_* values from the list of operations.
383 One of ``INSTANCE``, ``NODE``, ``CLUSTER``.
386 The path to the Ganeti configuration directory (to read, for
387 example, the *ssconf* files).
390 Specialised variables
391 ~~~~~~~~~~~~~~~~~~~~~
393 This is the list of variables which are specific to one or more
397 The name of the instance which is the target of the operation.
399 INSTANCE_DISK_TEMPLATE
400 The disk type for the instance.
403 The number of disks for the instance.
406 The size of disk *n* for the instance.
409 Either *rw* for a read-write disk or *ro* for a read-only one.
412 The number of NICs for the instance.
415 The bridge to which the *n* -th NIC of the instance is attached.
418 The IP (if any) of the *n* -th NIC of the instance.
421 The MAC address of the *n* -th NIC of the instance.
424 The name of the instance OS.
427 The name of the node which is the primary for the instance.
430 Space-separated list of secondary nodes for the instance.
433 The memory size (in MiBs) of the instance.
436 The number of virtual CPUs for the instance.
439 The run status of the instance.
442 The target node of this operation (not the node on which the hook
446 The primary IP of the target node (the one over which inter-node
447 communication is done).
450 The secondary IP of the target node (the one over which drbd
451 replication is done). This can be equal to the primary ip, in case
452 the cluster is not dual-homed.
455 This is provided by some operations when the user gave this flag.
458 The user has specified this flag. It is used when failing over
459 instances in case the primary node is down.
462 The mode of the instance create: either *create* for create from
463 scratch or *import* for restoring from an exported image.
465 SRC_NODE, SRC_PATH, SRC_IMAGE
466 In case the instance has been added by import, these variables are
467 defined and point to the source node, source path (the directory
468 containing the image and the config file) and the source disk image
472 The name of the node on which the new mirror component is being
473 added. This can be the name of the current secondary, if the new
474 mirror is on the same secondary.
477 The name of the old secondary in the replace-disks command Note that
478 this can be equal to the new secondary if the secondary node hasn't
482 The node on which the exported image of the instance was done.
485 This variable tells if the instance has been shutdown or not while
486 doing the export. In the "was shutdown" case, it's likely that the
487 filesystem is consistent, whereas in the "did not shutdown" case,
488 the filesystem would need a check (journal replay or full fsck) in
489 order to guarantee consistency.
492 The list of cluster tags, space separated.
495 The list of tags for node *<name>*, space separated.
500 The startup of an instance will pass this environment to the hook
503 GANETI_CLUSTER=cluster1.example.com
504 GANETI_DATA_DIR=/var/lib/ganeti
506 GANETI_HOOKS_PATH=instance-start
507 GANETI_HOOKS_PHASE=post
508 GANETI_HOOKS_VERSION=2
509 GANETI_INSTANCE_DISK0_MODE=rw
510 GANETI_INSTANCE_DISK0_SIZE=128
511 GANETI_INSTANCE_DISK_COUNT=1
512 GANETI_INSTANCE_DISK_TEMPLATE=drbd
513 GANETI_INSTANCE_MEMORY=128
514 GANETI_INSTANCE_NAME=instance2.example.com
515 GANETI_INSTANCE_NIC0_BRIDGE=xen-br0
516 GANETI_INSTANCE_NIC0_IP=
517 GANETI_INSTANCE_NIC0_MAC=aa:00:00:a5:91:58
518 GANETI_INSTANCE_NIC_COUNT=1
519 GANETI_INSTANCE_OS_TYPE=debootstrap
520 GANETI_INSTANCE_PRIMARY=node3.example.com
521 GANETI_INSTANCE_SECONDARIES=node5.example.com
522 GANETI_INSTANCE_STATUS=down
523 GANETI_INSTANCE_VCPUS=1
524 GANETI_MASTER=node1.example.com
525 GANETI_OBJECT_TYPE=INSTANCE
526 GANETI_OP_CODE=OP_INSTANCE_STARTUP
527 GANETI_OP_TARGET=instance2.example.com