gnt-os - Instance operating system administration


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


The gnt-os is used for managing the list of available operating system flavours for the instances in the Ganeti cluster.



list [–no-headers]

Gives the list of available/supported OS to use in the instances. When creating the instance you can give the OS-name as an option.

Note that hidden or blacklisted OSes are not displayed by this command, use diagnose for showing those.



This command will help you see why an installed OS is not available in the cluster. The list command shows only the OS-es that the cluster sees available on all nodes. It could be that some OS is missing from a node, or is only partially installed, and this command will show the details of all the OSes and the reasons they are or are not valid.


info {OS}

This command will list detailed information about each OS available in the cluster, including its validity status, the supported API versions, the supported parameters and variants (if any), and their documentation, etc. If an OS name is given, then only the specified OS details will be shown.

Note that this command besides the information about the given OS(es), shows detailed information about the given available/supported OS variant(s), in terms of the modified per-OS hypervisor parameters and the modified per-OS parameters passed to the OS install scripts.

For the list of the available OSes use list. Also, see modify for a description of how to modify the parameters for a specific operating system.


modify [–submit] [–print-jobid]
[ [ -O | –os-parameters ] =*option*=*value*]
[ –os-parameters-private=*option*=*value*]
[-H HYPERVISOR:option=*value*[,...]]
[–hidden=*yes|no*] [–blacklisted=*yes|no*]

This command will allow you to modify OS parameters.

To modify the per-OS hypervisor parameters (which override the global hypervisor parameters), you can run modify -H with the same syntax as in gnt-cluster init to override default hypervisor parameters of the cluster for specified OS argument.

To modify the parameters passed to the OS install scripts, use the –os-parameters option. If the value of the parameter should not be saved to logs, use –os-parameters-private and make sure that no Ganeti daemon or program is running in debug mode. ganeti-luxid in particular will issue a warning at startup time if ran in debug mode.

To modify the hidden and blacklisted states of an OS, pass the options --hidden yes|no, or respectively --blacklisted .... The ‘hidden’ state means that an OS won’t be listed by default in the OS list, but is available for installation. The ‘blacklisted’ state means that the OS is not listed and is also not allowed for new instance creations (but can be used for reinstalling old instances).

Note: The given operating system doesn’t have to exist. This allows preseeding the settings for operating systems not yet known to gnt-os.

See ganeti(7) for a description of --submit and other common options.