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, MASTER_CAPABLE, VM_CAPABLE
124 :pre-execution: all existing nodes
125 :post-execution: all nodes plus the new node
131 Removes a node from the cluster. On the removed node the hooks are
132 called during the execution of the operation and not after its
135 :directory: node-remove
136 :env. vars: NODE_NAME
137 :pre-execution: all existing nodes except the removed node
138 :post-execution: all existing nodes
143 Changes a node's parameters.
145 :directory: node-modify
146 :env. vars: MASTER_CANDIDATE, OFFLINE, DRAINED, MASTER_CAPABLE, VM_CAPABLE
147 :pre-execution: master node, the target node
148 :post-execution: master node, the target node
153 Relocate secondary instances from a node.
155 :directory: node-evacuate
156 :env. vars: NEW_SECONDARY, NODE_NAME
157 :pre-execution: master node, target node
158 :post-execution: master node, target node
163 Relocate secondary instances from a node.
165 :directory: node-migrate
166 :env. vars: NODE_NAME
167 :pre-execution: master node
168 :post-execution: master node
171 Node group operations
172 ~~~~~~~~~~~~~~~~~~~~~
177 Adds a node group to the cluster.
179 :directory: group-add
180 :env. vars: GROUP_NAME
181 :pre-execution: master node
182 :post-execution: master node
187 Changes a node group's parameters.
189 :directory: group-modify
190 :env. vars: GROUP_NAME, NEW_ALLOC_POLICY
191 :pre-execution: master node
192 :post-execution: master node
197 Removes a node group from the cluster. Since the node group must be
198 empty for removal to succeed, the concept of "nodes in the group" does
199 not exist, and the hook is only executed in the master node.
201 :directory: group-remove
202 :env. vars: GROUP_NAME
203 :pre-execution: master node
204 :post-execution: master node
209 Renames a node group.
211 :directory: group-rename
212 :env. vars: OLD_NAME, NEW_NAME
213 :pre-execution: master node and all nodes in the group
214 :post-execution: master node and all nodes in the group
220 All instance operations take at least the following variables:
221 INSTANCE_NAME, INSTANCE_PRIMARY, INSTANCE_SECONDARY,
222 INSTANCE_OS_TYPE, INSTANCE_DISK_TEMPLATE, INSTANCE_MEMORY,
223 INSTANCE_DISK_SIZES, INSTANCE_VCPUS, INSTANCE_NIC_COUNT,
224 INSTANCE_NICn_IP, INSTANCE_NICn_BRIDGE, INSTANCE_NICn_MAC,
225 INSTANCE_DISK_COUNT, INSTANCE_DISKn_SIZE, INSTANCE_DISKn_MODE.
227 The INSTANCE_NICn_* and INSTANCE_DISKn_* variables represent the
228 properties of the *n* -th NIC and disk, and are zero-indexed.
234 Creates a new instance.
236 :directory: instance-add
237 :env. vars: ADD_MODE, SRC_NODE, SRC_PATH, SRC_IMAGES
238 :pre-execution: master node, primary and secondary nodes
239 :post-execution: master node, primary and secondary nodes
241 OP_INSTANCE_REINSTALL
242 +++++++++++++++++++++
244 Reinstalls an instance.
246 :directory: instance-reinstall
247 :env. vars: only the standard instance vars
248 :pre-execution: master node, primary and secondary nodes
249 :post-execution: master node, primary and secondary nodes
254 Exports the instance.
256 :directory: instance-export
257 :env. vars: EXPORT_MODE, EXPORT_NODE, EXPORT_DO_SHUTDOWN, REMOVE_INSTANCE
258 :pre-execution: master node, primary and secondary nodes
259 :post-execution: master node, primary and secondary nodes
266 :directory: instance-start
268 :pre-execution: master node, primary and secondary nodes
269 :post-execution: master node, primary and secondary nodes
276 :directory: instance-stop
278 :pre-execution: master node, primary and secondary nodes
279 :post-execution: master node, primary and secondary nodes
286 :directory: instance-reboot
287 :env. vars: IGNORE_SECONDARIES, REBOOT_TYPE, SHUTDOWN_TIMEOUT
288 :pre-execution: master node, primary and secondary nodes
289 :post-execution: master node, primary and secondary nodes
291 OP_INSTANCE_SET_PARAMS
292 ++++++++++++++++++++++
294 Modifies the instance parameters.
296 :directory: instance-modify
297 :env. vars: NEW_DISK_TEMPLATE
298 :pre-execution: master node, primary and secondary nodes
299 :post-execution: master node, primary and secondary nodes
304 Failovers an instance. In the post phase INSTANCE_PRIMARY and
305 INSTANCE_SECONDARY refer to the nodes that were repectively primary
306 and secondary before failover.
308 :directory: instance-failover
309 :env. vars: IGNORE_CONSISTENCY, SHUTDOWN_TIMEOUT, OLD_PRIMARY, OLD_SECONDARY, NEW_PRIMARY, NEW_SECONDARY
310 :pre-execution: master node, secondary node
311 :post-execution: master node, primary and secondary nodes
316 Migrates an instance. In the post phase INSTANCE_PRIMARY and
317 INSTANCE_SECONDARY refer to the nodes that were repectively primary
318 and secondary before migration.
320 :directory: instance-migrate
321 :env. vars: MIGRATE_LIVE, MIGRATE_CLEANUP, OLD_PRIMARY, OLD_SECONDARY, NEW_PRIMARY, NEW_SECONDARY
322 :pre-execution: master node, secondary node
323 :post-execution: master node, primary and secondary nodes
331 :directory: instance-remove
332 :env. vars: SHUTDOWN_TIMEOUT
333 :pre-execution: master node
334 :post-execution: master node, primary and secondary nodes
336 OP_INSTANCE_REPLACE_DISKS
337 +++++++++++++++++++++++++
339 Replace an instance's disks.
341 :directory: mirror-replace
342 :env. vars: MODE, NEW_SECONDARY, OLD_SECONDARY
343 :pre-execution: master node, primary and secondary nodes
344 :post-execution: master node, primary and secondary nodes
346 OP_INSTANCE_GROW_DISK
347 +++++++++++++++++++++
349 Grows the disk of an instance.
351 :directory: disk-grow
352 :env. vars: DISK, AMOUNT
353 :pre-execution: master node, primary and secondary nodes
354 :post-execution: master node, primary and secondary nodes
361 :directory: instance-rename
362 :env. vars: INSTANCE_NEW_NAME
363 :pre-execution: master node, primary and secondary nodes
364 :post-execution: master node, primary and secondary nodes
369 Move an instance by data-copying.
371 :directory: instance-move
372 :env. vars: TARGET_NODE, SHUTDOWN_TIMEOUT
373 :pre-execution: master node, primary and target nodes
374 :post-execution: master node, primary and target nodes
376 OP_INSTANCE_RECREATE_DISKS
377 ++++++++++++++++++++++++++
379 Recreate an instance's missing disks.
381 :directory: instance-recreate-disks
382 :env. vars: only the standard instance vars
383 :pre-execution: master node, primary and secondary nodes
384 :post-execution: master node, primary and secondary nodes
386 OP_INSTANCE_REPLACE_DISKS
387 +++++++++++++++++++++++++
389 Replace the disks of an instance.
391 :directory: mirrors-replace
392 :env. vars: MODE, NEW_SECONDARY, OLD_SECONDARY
393 :pre-execution: master node, primary and new secondary nodes
394 :post-execution: master node, primary and new secondary nodes
403 This hook is called via a special "empty" LU right after cluster
406 :directory: cluster-init
409 :post-execution: master node
414 The post phase of this hook is called during the execution of destroy
415 operation and not after its completion.
417 :directory: cluster-destroy
420 :post-execution: master node
425 Verifies the cluster status. This is a special LU with regard to
426 hooks, as the result of the opcode will be combined with the result of
427 post-execution hooks, in order to allow administrators to enhance the
428 cluster verification procedure.
430 :directory: cluster-verify
431 :env. vars: CLUSTER, MASTER, CLUSTER_TAGS, NODE_TAGS_<name>
433 :post-execution: all nodes
440 :directory: cluster-rename
442 :pre-execution: master-node
443 :post-execution: master-node
445 OP_CLUSTER_SET_PARAMS
446 +++++++++++++++++++++
448 Modifies the cluster parameters.
450 :directory: cluster-modify
451 :env. vars: NEW_VG_NAME
452 :pre-execution: master node
453 :post-execution: master node
459 The following operations are no longer present or don't execute hooks
460 anymore in Ganeti 2.0:
464 - OP_INSTANCE_ADD_MDDRBD
465 - OP_INSTANCE_REMOVE_MDDRBD
468 Environment variables
469 ---------------------
471 Note that all variables listed here are actually prefixed with *GANETI_*
472 in order to provide a clear namespace. In addition, post-execution
473 scripts receive another set of variables, prefixed with *GANETI_POST_*,
474 representing the status after the opcode executed.
479 This is the list of environment variables supported by all operations:
482 Documents the hooks interface version. In case this doesnt match
483 what the script expects, it should not run. The documents conforms
487 One of *PRE* or *POST* denoting which phase are we in.
496 One of the *OP_* values from the list of operations.
499 One of ``INSTANCE``, ``NODE``, ``CLUSTER``.
502 The path to the Ganeti configuration directory (to read, for
503 example, the *ssconf* files).
506 Specialised variables
507 ~~~~~~~~~~~~~~~~~~~~~
509 This is the list of variables which are specific to one or more
513 The name of the instance which is the target of the operation.
515 INSTANCE_BE_x,y,z,...
516 Instance BE params. There is one variable per BE param. For instance, GANETI_INSTANCE_BE_auto_balance
518 INSTANCE_DISK_TEMPLATE
519 The disk type for the instance.
522 The new disk type for the instance.
525 The number of disks for the instance.
528 The size of disk *n* for the instance.
531 Either *rw* for a read-write disk or *ro* for a read-only one.
533 INSTANCE_HV_x,y,z,...
534 Instance hypervisor options. There is one variable per option. For instance, GANETI_INSTANCE_HV_use_bootloader
537 The instance hypervisor.
540 The number of NICs for the instance.
543 The bridge to which the *n* -th NIC of the instance is attached.
546 The IP (if any) of the *n* -th NIC of the instance.
549 The MAC address of the *n* -th NIC of the instance.
552 The mode of the *n* -th NIC of the instance.
555 The name of the instance OS.
558 The name of the node which is the primary for the instance. Note that
559 for migrations/failovers, you shouldn't rely on this variable since
560 the nodes change during the exectution, but on the
561 OLD_PRIMARY/NEW_PRIMARY values.
564 Space-separated list of secondary nodes for the instance. Note that
565 for migrations/failovers, you shouldn't rely on this variable since
566 the nodes change during the exectution, but on the
567 OLD_SECONDARY/NEW_SECONDARY values.
570 The memory size (in MiBs) of the instance.
573 The number of virtual CPUs for the instance.
576 The run status of the instance.
579 Whether a node is capable of being promoted to master.
582 Whether the node can host instances.
585 The target node of this operation (not the node on which the hook
589 The primary IP of the target node (the one over which inter-node
590 communication is done).
593 The secondary IP of the target node (the one over which drbd
594 replication is done). This can be equal to the primary ip, in case
595 the cluster is not dual-homed.
598 This is provided by some operations when the user gave this flag.
601 The user has specified this flag. It is used when failing over
602 instances in case the primary node is down.
605 The mode of the instance create: either *create* for create from
606 scratch or *import* for restoring from an exported image.
608 SRC_NODE, SRC_PATH, SRC_IMAGE
609 In case the instance has been added by import, these variables are
610 defined and point to the source node, source path (the directory
611 containing the image and the config file) and the source disk image
615 The name of the node on which the new mirror component is being
616 added (for replace disk). This can be the name of the current
617 secondary, if the new mirror is on the same secondary. For
618 migrations/failovers, this is the old primary node.
621 The name of the old secondary in the replace-disks command. Note that
622 this can be equal to the new secondary if the secondary node hasn't
623 actually changed. For migrations/failovers, this is the new primary
626 OLD_PRIMARY, NEW_PRIMARY
627 For migrations/failovers, the old and respectively new primary
628 nodes. These two mirror the NEW_SECONDARY/OLD_SECONDARY variables
631 The instance export mode. Either "remote" or "local".
634 The node on which the exported image of the instance was done.
637 This variable tells if the instance has been shutdown or not while
638 doing the export. In the "was shutdown" case, it's likely that the
639 filesystem is consistent, whereas in the "did not shutdown" case,
640 the filesystem would need a check (journal replay or full fsck) in
641 order to guarantee consistency.
644 Whether the instance was removed from the node.
647 Amount of time to wait for the instance to shutdown.
650 Amount of time to wait before aborting the op.
653 Old/new name of the node group.
656 The name of the node group.
659 The new allocation policy for the node group.
662 The list of cluster tags, space separated.
665 The list of tags for node *<name>*, space separated.
670 The startup of an instance will pass this environment to the hook
673 GANETI_CLUSTER=cluster1.example.com
674 GANETI_DATA_DIR=/var/lib/ganeti
676 GANETI_HOOKS_PATH=instance-start
677 GANETI_HOOKS_PHASE=post
678 GANETI_HOOKS_VERSION=2
679 GANETI_INSTANCE_DISK0_MODE=rw
680 GANETI_INSTANCE_DISK0_SIZE=128
681 GANETI_INSTANCE_DISK_COUNT=1
682 GANETI_INSTANCE_DISK_TEMPLATE=drbd
683 GANETI_INSTANCE_MEMORY=128
684 GANETI_INSTANCE_NAME=instance2.example.com
685 GANETI_INSTANCE_NIC0_BRIDGE=xen-br0
686 GANETI_INSTANCE_NIC0_IP=
687 GANETI_INSTANCE_NIC0_MAC=aa:00:00:a5:91:58
688 GANETI_INSTANCE_NIC_COUNT=1
689 GANETI_INSTANCE_OS_TYPE=debootstrap
690 GANETI_INSTANCE_PRIMARY=node3.example.com
691 GANETI_INSTANCE_SECONDARY=node5.example.com
692 GANETI_INSTANCE_STATUS=down
693 GANETI_INSTANCE_VCPUS=1
694 GANETI_MASTER=node1.example.com
695 GANETI_OBJECT_TYPE=INSTANCE
696 GANETI_OP_CODE=OP_INSTANCE_STARTUP
697 GANETI_OP_TARGET=instance2.example.com
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