gnt-instance

ADD

add
{-t {diskless | file | plain | drbd}}
{--disk=N: {size=VAL | adopt=LV},mode=ro|rw | -s SIZE}
[--no-ip-check] [--no-name-check] [--no-start] [--no-install]
[--net=N [:options...] | --no-nics]
[-B BEPARAMS]
[-H HYPERVISOR [: option=value... ]]
[--file-storage-dir dir_path] [--file-driver {loop | blktap}]
{-n node[:secondary-node] | --iallocator name}
{-o os-type}
[--submit]
{instance}

Creates a new instance on the specified host. The instance argument must be in DNS, but depending on the bridge/routing setup, need not be in the same network as the nodes in the cluster.

The disk option specifies the parameters for the disks of the instance. The numbering of disks starts at zero, and at least one disk needs to be passed. For each disk, either the size or the adoption source needs to be given, and optionally the access mode (read-only or the default of read-write) can also be specified. The size is interpreted (when no unit is given) in mebibytes. You can also use one of the suffixes m, g or t to specify the exact the units used; these suffixes map to mebibytes, gibibytes and tebibytes.

When using the adopt key in the disk definition, Ganeti will reuse those volumes (instead of creating new ones) as the instance's disks. Ganeti will rename these volumes to the standard format, and (without installing the OS) will use them as-is for the instance. This allows migrating instances from non-managed mode (e.q. plain KVM with LVM) to being managed via Ganeti. Note that this works only for the `plain' disk template (see below for template details).

Alternatively, a single-disk instance can be created via the -s option which takes a single argument, the size of the disk. This is similar to the Ganeti 1.2 version (but will only create one disk).

The minimum disk specification is therefore --disk 0:size=20G (or -s 20G when using the -s option), and a three-disk instance can be specified as --disk 0:size=20G --disk 1:size=4G --disk 2:size=100G.

The --no-ip-check skips the checks that are done to see if the instance's IP is not already alive (i.e. reachable from the master node).

The --no-name-check skips the check for the instance name via the resolver (e.g. in DNS or /etc/hosts, depending on your setup). Since the name check is used to compute the IP address, if you pass this option you must also pass the --no-ip-check option.

If you don't wat the instance to automatically start after creation, this is possible via the --no-start option. This will leave the instance down until a subsequent gnt-instance start command.

The NICs of the instances can be specified via the --net option. By default, one NIC is created for the instance, with a random MAC, and set up according the the cluster level nic parameters. Each NIC can take these parameters (all optional):

Alternatively, if no network is desired for the instance, you can prevent the default of one NIC with the --no-nics option.

The -o options specifies the operating system to be installed. The available operating systems can be listed with gnt-os list. Passing --no-install will however skip the OS installation, allowing a manual import if so desired. Note that the no-installation mode will automatically disable the start-up of the instance (without an OS, it most likely won't be able to start-up successfully).

The -B option specifies the backend parameters for the instance. If no such parameters are specified, the values are inherited from the cluster. Possible parameters are:

The -H option specified the hypervisor to use for the instance (must be one of the enabled hypervisors on the cluster) and optionally custom parameters for this instance. If not other options are used (i.e. the invocation is just -H NAME) the instance will inherit the cluster options. The defaults below show the cluster defaults at cluster creation time.

The possible hypervisor options are as follows:

The --iallocator option specifies the instance allocator plugin to use. If you pass in this option the allocator will select nodes for this instance automatically, so you don't need to pass them with the -n option. For more information please refer to the instance allocator documentation.

The -t options specifies the disk layout type for the instance. The available choices are:

The optional second value of the --node is used for the drbd template type and specifies the remote node.

If you do not want gnt-instance to wait for the disk mirror to be synced, use the --no-wait-for-sync option.

The --file-storage-dir specifies the relative path under the cluster-wide file storage directory to store file-based disks. It is useful for having different subdirectories for different instances. The full path of the directory where the disk files are stored will consist of cluster-wide file storage directory + optional subdirectory + instance name. Example: /srv/ganeti/file-storage/mysubdir/instance1.example.com. This option is only relevant for instances using the file storage backend.

The --file-driver specifies the driver to use for file-based disks. Note that currently these drivers work with the xen hypervisor only. This option is only relevant for instances using the file storage backend. The available choices are:

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

Example:

# gnt-instance add -t file --disk 0:size=30g -B memory=512 -o debian-etch \
  -n node1.example.com --file-storage-dir=mysubdir instance1.example.com
# gnt-instance add -t plain --disk 0:size=30g -B memory=512 -o debian-etch \
  -n node1.example.com instance1.example.com
# gnt-instance add -t drbd --disk 0:size=30g -B memory=512 -o debian-etch \
  -n node1.example.com:node2.example.com instance2.example.com
          

BATCH-CREATE

batch-create {instances_file.json}

This command (similar to the Ganeti 1.2 batcher tool) submits multiple instance creation jobs based on a definition file. The instance configurations do not encompass all the possible options for the add command, but only a subset.

The instance file should be a valid-formed JSON file, containing a dictionary with instance name and instance parameters. The accepted parameters are:

A simple definition for one instance can be (with most of the parameters taken from the cluster defaults):

{
  "instance3": {
    "template": "drbd",
    "os": "debootstrap",
    "disk_size": ["25G"],
    "iallocator": "dumb"
  },
  "instance5": {
    "template": "drbd",
    "os": "debootstrap",
    "disk_size": ["25G"],
    "iallocator": "dumb",
    "hypervisor": "xen-hvm",
    "hvparams": {"acpi": true},
    "backend": {"memory": 512}
  }
}

The command will display the job id for each submitted instance, as follows:

# gnt-instance batch-create instances.json
instance3: 11224
instance5: 11225

REMOVE

remove [--ignore-failures] [--shutdown-timeout=N] [--submit] {instance}

Remove an instance. This will remove all data from the instance and there is no way back. If you are not sure if you use an instance again, use shutdown first and leave it in the shutdown state for a while.

The --ignore-failures option will cause the removal to proceed even in the presence of errors during the removal of the instance (e.g. during the shutdown or the disk removal). If this option is not given, the command will stop at the first error.

The --shutdown-timeout is used to specify how much time to wait before forcing the shutdown (xm destroy in xen, killing the kvm process, for kvm). By default two minutes are given to each instance to stop.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

Example:

# gnt-instance remove instance1.example.com
          

LIST

list [--no-headers] [--separator=SEPARATOR]
[--units=UNITS] [-o [+]FIELD,...] [--roman] [instance...]

Shows the currently configured instances with memory usage, disk usage, the node they are running on, and their run status.

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 units used to display the numeric values in the output varies, depending on the options given. By default, the values will be formatted in the most appropriate unit. If the --separator option is given, then the values are shown in mebibytes to allow parsing by scripts. In both cases, the --units option can be used to enforce a given output unit.

The --roman option allows latin people to better understand the cluster instances' status.

The -o option takes a comma-separated list of output fields. The available fields and their meaning are:

If the value of the option starts with the character +, the new field(s) will be added to the default list. This allows to quickly see the default list plus a few other fields, instead of retyping the entire list of fields.

There is a subtle grouping about the available output fields: all fields except for oper_state, oper_ram, oper_vcpus and status are configuration value and not run-time values. So if you don't select any of the these fields, the query will be satisfied instantly from the cluster configuration, without having to ask the remote nodes for the data. This can be helpful for big clusters when you only want some data and it makes sense to specify a reduced set of output fields.

The default output field list is: name, os, pnode, admin_state, oper_state, oper_ram.

INFO

info [-s | --static] [--roman] {--all | instance}

Show detailed information about the given instance(s). This is different from list as it shows detailed data about the instance's disks (especially useful for the drbd disk template).

If the option -s is used, only information available in the configuration file is returned, without querying nodes, making the operation faster.

Use the --all to get info about all instances, rather than explicitly passing the ones you're interested in.

The --roman option can be used to cause envy among people who like ancient cultures, but are stuck with non-latin-friendly cluster virtualization technologies.

MODIFY

modify
[-H HYPERVISOR_PARAMETERS]
[-B BACKEND_PARAMETERS]
[--net add[:options] | --net remove | --net N:options]
[--disk add:size=SIZE | --disk remove | --disk N:mode=MODE]
[-t {plain | drbd}]
[--os-name=OS [--force-variant]]
[--submit]
{instance}

Modifies the memory size, number of vcpus, ip address, MAC address and/or nic parameters for an instance. It can also add and remove disks and NICs to/from the instance. Note that you need to give at least one of the arguments, otherwise the command complains.

The -H option specifies hypervisor options in the form of name=value[,...]. For details which options can be specified, see the add command.

The -t option will change the disk template of the instance. Currently only conversions between the plain and drbd disk templates are supported, and the instance must be stopped before attempting the conversion. When changing from the plain to the drbd disk template, a new secondary node must be specified via the -n option.

The --disk add:size=SIZE option adds a disk to the instance. The --disk remove will remove the last disk of the instance. The --disk N:mode=MODE option will change the mode of the Nth disk of the instance between read-only (ro) and read-write (rw).

The --net add:options option will add a new NIC to the instance. The available options are the same as in the add command (mac, ip, link, mode). The --net remove will remove the last NIC of the instance, while the --net N:options option will change the parameters of the Nth instance NIC.

The option --os-name will change the OS name for the instance (without reinstallation). In case an OS variant is specified that is not found, then by default the modification is refused, unless --force-variant is passed. An invalid OS will also be refused, unless the --force option is given.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

All the changes take effect at the next restart. If the instance is running, there is no effect on the instance.

REINSTALL

reinstall [-o os-type] [--select-os] [-f force] [--force-multiple]
[--instance | --node | --primary | --secondary | --all] [--submit] [instance...]

Reinstalls the operating system on the given instance(s). The instance(s) must be stopped when running this command. If the --os-type is specified, the operating system is changed.

The --select-os option switches to an interactive OS reinstall. The user is prompted to select the OS template from the list of available OS templates.

Since this is a potentially dangerous command, the user will be required to confirm this action, unless the -f flag is passed. When multiple instances are selected (either by passing multiple arguments or by using the --node, --primary, --secondary or --all options), the user must pass the --force-multiple options to skip the interactive confirmation.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

RENAME

rename [--no-ip-check] [--no-name-check] [--submit] {instance} {new_name}

Renames the given instance. The instance must be stopped when running this command. The requirements for the new name are the same as for adding an instance: the new name must be resolvable and the IP it resolves to must not be reachable (in order to prevent duplicate IPs the next time the instance is started). The IP test can be skipped if the --no-ip-check option is passed.

The --no-name-check skips the check for the new instance name via the resolver (e.g. in DNS or /etc/hosts, depending on your setup). Since the name check is used to compute the IP address, if you pass this option you must also pass the --no-ip-check option.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

STARTUP

startup
[--force]
[--force-multiple]
[--instance | --node | --primary | --secondary | --all | --tags | --node-tags | --pri-node-tags | --sec-node-tags]
[-H key=value...] [-B key=value...]
[--submit]
[name...]

Starts one or more instances, depending on the following options. The four available modes are:

Note that although you can pass more than one selection option, the last one wins, so in order to guarantee the desired result, don't pass more than one such option.

Use --force to start even if secondary disks are failing.

The --force-multiple will skip the interactive confirmation in the case the more than one instance will be affected.

The -H and -B options specify temporary hypervisor and backend parameters that can be used to start an instance with modified parameters. They can be useful for quick testing without having to modify an instance back and forth, e.g.:

# gnt-instance start -H root_args="single" instance1
# gnt-instance start -B memory=2048 instance2
          

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

Example:

# gnt-instance start instance1.example.com
# gnt-instance start --node node1.example.com node2.example.com
# gnt-instance start --all
          

SHUTDOWN

shutdown
[--timeout=N]
[--force-multiple]
[--instance | --node | --primary | --secondary | --all | --tags | --node-tags | --pri-node-tags | --sec-node-tags]
[--submit]
[name...]

Stops one or more instances. If the instance cannot be cleanly stopped during a hardcoded interval (currently 2 minutes), it will forcibly stop the instance (equivalent to switching off the power on a physical machine).

The --timeout is used to specify how much time to wait before forcing the shutdown (xm destroy in xen, killing the kvm process, for kvm). By default two minutes are given to each instance to stop.

The --instance, --node, --primary, --secondary, --all, --tags, --node-tags, --pri-node-tags and --sec-node-tags options are similar as for the startup command and they influence the actual instances being shutdown.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

Example:

# gnt-instance shutdown instance1.example.com
# gnt-instance shutdown --all
          

REBOOT

reboot
[--type=REBOOT-TYPE]
[--ignore-secondaries]
[--shutdown-timeout=N]
[--force-multiple]
[--instance | --node | --primary | --secondary | --all | --tags | --node-tags | --pri-node-tags | --sec-node-tags]
[--submit]
[name...]

Reboots one or more instances. The type of reboot depends on the value of --type. A soft reboot does a hypervisor reboot, a hard reboot does a instance stop, recreates the hypervisor config for the instance and starts the instance. A full reboot does the equivalent of gnt-instance shutdown && gnt-instance startup. The default is hard reboot.

For the hard reboot the option --ignore-secondaries ignores errors for the secondary node while re-assembling the instance disks.

The --instance, --node, --primary, --secondary, --all, --tags, --node-tags, --pri-node-tags and --sec-node-tags options are similar as for the startup command and they influence the actual instances being rebooted.

The --shutdown-timeout is used to specify how much time to wait before forcing the shutdown (xm destroy in xen, killing the kvm process, for kvm). By default two minutes are given to each instance to stop.

The --force-multiple will skip the interactive confirmation in the case the more than one instance will be affected.

Example:

# gnt-instance reboot instance1.example.com
# gnt-instance reboot --type=full instance1.example.com
          

CONSOLE

console [--show-cmd] {instance}

Connects to the console of the given instance. If the instance is not up, an error is returned. Use the --show-cmd option to display the command instead of executing it.

For HVM instances, this will attempt to connect to the serial console of the instance. To connect to the virtualized "physical" console of a HVM instance, use a VNC client with the connection info from the info command.

Example:

# gnt-instance console instance1.example.com
          

REPLACE-DISKS

replace-disks [--submit] [--early-release] {-p} [--disks idx] {instance}

replace-disks [--submit] [--early-release] {-s} [--disks idx] {instance}

replace-disks [--submit] [--early-release] {--iallocator name | --new-secondary NODE} {instance}

replace-disks [--submit] [--early-release] {--auto} {instance}

This command is a generalized form for replacing disks. It is currently only valid for the mirrored (DRBD) disk template.

The first form (when passing the -p option) will replace the disks on the primary, while the second form (when passing the -s option will replace the disks on the secondary node. For these two cases (as the node doesn't change), it is possible to only run the replace for a subset of the disks, using the option --disks which takes a list of comma-delimited disk indices (zero-based), e.g. 0,2 to replace only the first and third disks.

The third form (when passing either the --iallocator or the --new-secondary option) is designed to change secondary node of the instance. Specifying --iallocator makes the new secondary be selected automatically by the specified allocator plugin, otherwise the new secondary node will be the one chosen manually via the --new-secondary option.

The fourth form (when using --auto) will automatically determine which disks of an instance are faulty and replace them within the same node. The --auto option works only when an instance has only faulty disks on either the primary or secondary node; it doesn't work when both sides have faulty disks.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

The --early-release changes the code so that the old storage on secondary node(s) is removed early (before the resync is completed) and the internal Ganeti locks for the current (and new, if any) secondary node are also released, thus allowing more parallelism in the cluster operation. This should be used only when recovering from a disk failure on the current secondary (thus the old storage is already broken) or when the storage on the primary node is known to be fine (thus we won't need the old storage for potential recovery).

Note that it is not possible to select an offline or drained node as a new secondary.

ACTIVATE-DISKS

activate-disks [--submit] [--ignore-size] {instance}

Activates the block devices of the given instance. If successful, the command will show the location and name of the block devices:

node1.example.com:disk/0:/dev/drbd0
node1.example.com:disk/1:/dev/drbd1
          

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

The --ignore-size option can be used to activate disks ignoring the currently configured size in Ganeti. This can be used in cases where the configuration has gotten out of sync with the real-world (e.g. after a partially-failed grow-disk operation or due to rounding in LVM devices). This should not be used in normal cases, but only when activate-disks fails without it.

Note that it is safe to run this command while the instance is already running.

DEACTIVATE-DISKS

deactivate-disks [--submit] {instance}

De-activates the block devices of the given instance. Note that if you run this command for an instance with a drbd disk template, while it is running, it will not be able to shutdown the block devices on the primary node, but it will shutdown the block devices on the secondary nodes, thus breaking the replication.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

GROW-DISK

grow-disk [--no-wait-for-sync] [--submit] {instance} {disk} {amount}

Grows an instance's disk. This is only possible for instances having a plain or drbd disk template.

Note that this command only change the block device size; it will not grow the actual filesystems, partitions, etc. that live on that disk. Usually, you will need to:

1. use gnt-instance grow-disk

2. reboot the instance (later, at a convenient time)

3. use a filesystem resizer, such as ext2online(8) or xfs_growfs(8) to resize the filesystem, or use fdisk(8) to change the partition table on the disk

The disk argument is the index of the instance disk to grow. The amount argument is given either as a number (and it represents the amount to increase the disk with in mebibytes) or can be given similar to the arguments in the create instance operation, with a suffix denoting the unit.

Note that the disk grow operation might complete on one node but fail on the other; this will leave the instance with different-sized LVs on the two nodes, but this will not create problems (except for unused space).

If you do not want gnt-instance to wait for the new disk region to be synced, use the --no-wait-for-sync option.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

Example (increase the first disk for instance1 by 16GiB):

# gnt-instance grow-disk instance1.example.com 0 16g
          

Also note that disk shrinking is not supported; use gnt-backup export and then gnt-backup import to reduce the disk size of an instance.

RECREATE-DISKS

recreate-disks [--submit] [--disks=indices] {instance}

Recreates the disks of the given instance, or only a subset of the disks (if the option disks is passed, which must be a comma-separated list of disk indices, starting from zero).

Note that this functionality should only be used for missing disks; if any of the given disks already exists, the operation will fail. While this is suboptimal, recreate-disks should hopefully not be needed in normal operation and as such the impact of this is low.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

FAILOVER

failover [-f] [--ignore-consistency] [--shutdown-timeout=N] [--submit] {instance}

Failover will fail the instance over its secondary node. This works only for instances having a drbd disk template.

Normally the failover will check the consistency of the disks before failing over the instance. If you are trying to migrate instances off a dead node, this will fail. Use the --ignore-consistency option for this purpose. Note that this option can be dangerous as errors in shutting down the instance will be ignored, resulting in possibly having the instance running on two machines in parallel (on disconnected DRBD drives).

The --shutdown-timeout is used to specify how much time to wait before forcing the shutdown (xm destroy in xen, killing the kvm process, for kvm). By default two minutes are given to each instance to stop.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

Example:

# gnt-instance failover instance1.example.com
          

MIGRATE

migrate [-f] {--cleanup} {instance}

migrate [-f] [--non-live] [--migration-mode=live|non-live] {instance}

Migrate will move the instance to its secondary node without shutdown. It only works for instances having the drbd8 disk template type.

The migration command needs a perfectly healthy instance, as we rely on the dual-master capability of drbd8 and the disks of the instance are not allowed to be degraded.

The --non-live and --migration-mode=non-live options will switch (for the hypervisors that support it) between a "fully live" (i.e. the interruption is as minimal as possible) migration and one in which the instance is frozen, its state saved and transported to the remote node, and then resumed there. This all depends on the hypervisor support for two different methods. In any case, it is not an error to pass this parameter (it will just be ignored if the hypervisor doesn't support it). The option --migration-mode=live option will request a fully-live migration. The default, when neither option is passed, depends on the hypervisor parameters (and can be viewed with the gnt-cluster info command).

If the --cleanup option is passed, the operation changes from migration to attempting recovery from a failed previous migration. In this mode, Ganeti checks if the instance runs on the correct node (and updates its configuration if not) and ensures the instances's disks are configured correctly. In this mode, the --non-live option is ignored.

The option -f will skip the prompting for confirmation.

Example (and expected output):

# gnt-instance migrate instance1
Migrate will happen to the instance instance1. Note that migration is
**experimental** in this version. This might impact the instance if
anything goes wrong. Continue?
y/[n]/?: y
* checking disk consistency between source and target
* ensuring the target is in secondary mode
* changing disks into dual-master mode
 - INFO: Waiting for instance instance1 to sync disks.
 - INFO: Instance instance1's disks are in sync.
* migrating instance to node2.example.com
* changing the instance's disks on source node to secondary
 - INFO: Waiting for instance instance1 to sync disks.
 - INFO: Instance instance1's disks are in sync.
* changing the instance's disks to single-master
#
          

MOVE

move [-f] [-n node] [--shutdown-timeout=N] [--submit] {instance}

Move will move the instance to an arbitrary node in the cluster. This works only for instances having a plain or file disk template.

Note that since this operation is done via data copy, it will take a long time for big disks (similar to replace-disks for a drbd instance).

The --shutdown-timeout is used to specify how much time to wait before forcing the shutdown (xm destroy in xen, killing the kvm process, for kvm). By default two minutes are given to each instance to stop.

The --submit option is used to send the job to the master daemon but not wait for its completion. The job ID will be shown so that it can be examined via gnt-job info.

Example:

# gnt-instance move -n node3.example.com instance1.example.com
          

ADD-TAGS

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

Add tags to the given instance. 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

list-tags {instancename}

List the tags of the given instance.

REMOVE-TAGS

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

Remove tags from the given instance. 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 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.