gnt-group(8) Ganeti | Version 2.5.2


gnt-group - Ganeti node-group administration


gnt-group {command} [arguments...]


The gnt-group command is used for node group administration in the Ganeti system.




Creates a new group with the given name. The node group will be initially empty; to add nodes to it, use gnt-group assign-nodes.

The --node-parameters option allows you to set default node parameters for nodes in the group. Please see ganeti(7) for more information about supported key=value pairs.

The --alloc-policy option allows you to set an allocation policy for the group at creation time. Possible values are:


nodes in the group should not be candidates for instance allocation, and the operation (e.g., instance creation) should fail if only groups in this state could be found to satisfy the requirements.


nodes in the group should not be used for instance allocations, unless this would be the only way to have the operation succeed.


nodes in the group can be used freely for allocation of instances (this is the default). Note that prioritization among groups in this state will be deferred to the iallocator plugin that's being used.


{group} {node...}

Assigns one or more nodes to the specified group, moving them from their original group (or groups).

By default, this command will refuse to proceed if the move would split between groups any instance that was not previously split (a split instance is an instance with a mirrored disk template, e.g. DRBD, that has the primary and secondary nodes in different node groups). You can force the operation with --force.



Modifies some parameters from the node group.

The --node-parameters and --alloc-policy optiosn are documented in the add command above.


remove {group}

Deletes the indicated node group, which must be empty. There must always be at least one group, so the last group cannot be removed.


list [--no-headers] [--separator=SEPARATOR] [-v]
[-o [+]FIELD,...] [--filter] [group...]

Lists all existing node groups in the cluster.

The --no-headers option will skip the initial header line. The --separator option takes an argument which denotes what will be used between the output fields. Both these options are to help scripting.

The -v option activates verbose mode, which changes the display of special field states (see ganeti(7)).

The -o option takes a comma-separated list of output fields. If the value of the option starts with the character +, the new fields will be added to the default list. This allows one to quickly see the default list plus a few other fields, instead of retyping the entire list of fields.

The available fields and their meaning are:


Allocation policy for group


Creation timestamp


Modification timestamp


Group name


Node parameters


Number of nodes


List of nodes


Number of primary instances


List of primary instances


Group object serial number, incremented on each modification




Group UUID

If exactly one argument is given and it appears to be a query filter (see ganeti(7)), the query result is filtered accordingly. For ambiguous cases (e.g. a single field name as a filter) the --filter (-F) option forces the argument to be treated as a filter.

If no group names are given, then all groups are included. Otherwise, only the named groups will be listed.


list-fields [field...]

List available fields for node groups.


rename {oldname} {newname}

Renames a given group from oldname to newname.


evacuate [--iallocator NAME] [--to GROUP...] {group}

This command will move all instances out of the given node group. Instances are placed in a new group by an iallocator, either given on the command line or as a cluster default.

If no specific destination groups are specified using --to, all groups except the evacuated group are considered.


# gnt-group evacuate -I hail --to rack4 rack1



add-tags [--from file] {groupname} {tag...}

Add tags to the given node group. If any of the tags contains invalid characters, the entire operation will abort.

If the --from option is given, the list of tags will be extended with the contents of that file (each line becomes a tag). In this case, there is not need to pass tags on the command line (if you do, both sources will be used). A file name of - will be interpreted as stdin.


list-tags {groupname}

List the tags of the given node group.


remove-tags [--from file] {groupname} {tag...}

Remove tags from the given node group. If any of the tags are not existing on the node, the entire operation will abort.

If the --from option is given, the list of tags to be removed will be extended with the contents of that file (each line becomes a tag). In this case, there is not need to pass tags on the command line (if you do, tags from both sources will be removed). A file name of - will be interpreted as stdin.


Report bugs to project website or contact the developers using the Ganeti mailing list.


Ganeti overview and specifications: ganeti(7) (general overview), ganeti-os-interface(7) (guest OS definitions).

Ganeti commands: gnt-cluster(8) (cluster-wide commands), gnt-job(8) (job-related commands), gnt-node(8) (node-related commands), gnt-instance(8) (instance commands), gnt-os(8) (guest OS commands), gnt-group(8) (node group commands), gnt-backup(8) (instance import/export commands), gnt-debug(8) (debug commands).

Ganeti daemons: ganeti-watcher(8) (automatic instance restarter), ganeti-cleaner(8) (job queue cleaner), ganeti-noded(8) (node daemon), ganeti-masterd(8) (master daemon), ganeti-rapi(8) (remote API daemon).

Ganeti htools: htools(1) (generic binary), hbal(1) (cluster balancer), hspace(1) (capacity calculation), hail(1) (IAllocator plugin), hscan(1) (data gatherer from remote clusters).