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gnt-backup(8) Ganeti | Version @GANETI_VERSION@

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Name

----

gnt-backup - Ganeti instance import/export

Synopsis

--------

**gnt-backup** {command} [arguments...]

DESCRIPTION

-----------

The **gnt-backup** is used for importing and exporting instances

and their configuration from a Ganeti system. It is useful for

backing up instances and also to migrate them between clusters.

COMMANDS

--------

EXPORT

~~~~~~

**export** {-n *node*} [--shutdown-timeout=*N*] [--noshutdown]

[--remove-instance] [--ignore-remove-failures] {*instance*}

Exports an instance to the target node. All the instance data and

its configuration will be exported under the

``@CUSTOM_EXPORT_DIR@/``*instance* directory on the target node.

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 ``--noshutdown`` option will create a snapshot disk of the

instance without shutting it down first. While this is faster and

involves no downtime, it cannot be guaranteed that the instance

data will be in a consistent state in the exported dump.

The ``--remove`` option can be used to remove the instance after it

was exported. This is useful to make one last backup before

removing the instance.

The exit code of the command is 0 if all disks were backed up

successfully, 1 if no data was backed up or if the configuration

export failed, and 2 if just some of the disks failed to backup.

The exact details of the failures will be shown during the command

execution (and will be stored in the job log). It is recommended

that for any non-zero exit code, the backup is considered invalid,

and retried.

Example::

    # gnt-backup export -n node1.example.com instance3.example.com

IMPORT

~~~~~~

| **import**

| {-n *node[:secondary-node]* | --iallocator *name*}

| [--disk *N*:size=*VAL* [,vg=*VG*], [,mode=*ro|rw*]...]

| [--net *N* [:options...] | --no-nics]

| [-B *BEPARAMS*]

| [-H *HYPERVISOR* [: option=*value*... ]]

| [--src-node=*source-node*] [--src-dir=*source-dir*]

| [-t [diskless | plain | drbd | file]]

| [--identify-defaults]

| {*instance*}

Imports a new instance from an export residing on *source-node* in

*source-dir*. *instance* must be in DNS and resolve to a IP in the

same network as the nodes in the cluster. If the source node and

directory are not passed, the last backup in the cluster is used,

as visible with the **list** command.

The ``disk`` option specifies the parameters for the disks of the

instance. The numbering of disks starts at zero. For each disk, at

least the size needs to be given, and optionally the access mode

(read-only or the default of read-write) and LVM volume group 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 specificy

the exact the units used; these suffixes map to mebibytes, gibibytes

and tebibytes.

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).

If no disk information is passed, the disk configuration saved at

export time will be used.

The minimum disk specification is therefore empty (export information

will be used), a single disk can be specified as ``--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 NICs of the instances can be specified via the ``--net``

option. By default, the NIC configuration of the original

(exported) instance will be reused. Each NIC can take up to three

parameters (all optional):

mac

    either a value or ``generate`` to generate a new unique MAC, or

    ``auto`` to reuse the old MAC

ip

    specifies the IP address assigned to the instance from the Ganeti

    side (this is not necessarily what the instance will use, but what

    the node expects the instance to use)

mode

    specifies the connection mode for this nic: ``routed`` or

    ``bridged``.

link

    in bridged mode specifies the bridge to attach this NIC to, in

    routed mode it's intended to differentiate between different

    routing tables/instance groups (but the meaning is dependent on

    the network script in use, see **gnt-cluster**(8) for more

    details)

Of these ``mode`` and ``link`` are nic parameters, and inherit their

default at cluster level.

If no network is desired for the instance, you should create a single

empty NIC and delete it afterwards via **gnt-instance modify --net

delete**.

The ``-B`` option specifies the backend parameters for the

instance. If no such parameters are specified, the values are

inherited from the export. Possible parameters are:

maxmem

    the maximum memory size of the instance; as usual, suffixes can be

    used to denote the unit, otherwise the value is taken in mebibytes

minmem

    the minimum memory size of the instance; as usual, suffixes can be

    used to denote the unit, otherwise the value is taken in mebibytes

vcpus

    the number of VCPUs to assign to the instance (if this value makes

    sense for the hypervisor)

auto_balance

    whether the instance is considered in the N+1 cluster checks

    (enough redundancy in the cluster to survive a node failure)

always\_failover

    ``True`` or ``False``, whether the instance must be failed over

    (shut down and rebooted) always or it may be migrated (briefly

    suspended)

The ``-t`` options specifies the disk layout type for the instance.

If not passed, the configuration of the original instance is used.

The available choices are:

diskless

    This creates an instance with no disks. Its useful for testing only

    (or other special cases).

plain

    Disk devices will be logical volumes.

drbd

    Disk devices will be drbd (version 8.x) on top of lvm volumes.

file

    Disk devices will be backed up by files, under the directory

    ``@RPL_FILE_STORAGE_DIR@``. By default, each instance will get a

    directory (as its own name) under this path, and each disk is

    stored as individual files in this (instance-specific) directory.

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 optional second value of the ``--node`` is used for the drbd

template and specifies the remote node.

The ``--src-dir`` option allows importing instances from a directory

below ``@CUSTOM_EXPORT_DIR@``.

Since many of the parameters are by default read from the exported

instance information and used as such, the new instance will have

all parameters explicitly specified, the opposite of a newly added

instance which has most parameters specified via cluster defaults.

To change the import behaviour to recognize parameters whose saved

value matches the current cluster default and mark it as such

(default value), pass the ``--identify-defaults`` option. This will

affect the hypervisor, backend and NIC parameters, both read from

the export file and passed in via the command line.

Example for identical instance import::

    # gnt-backup import -n node1.example.com instance3.example.com

Explicit configuration example::

    # gnt-backup import -t plain --disk 0:size=1G -B memory=512 \

    > -n node1.example.com \

    > instance3.example.com

LIST

~~~~

**list** [--node=*NODE*]

Lists the exports currently available in the default directory in

all the nodes of the current cluster, or optionally only a subset

of them specified using the ``--node`` option (which can be used

multiple times)

Example::

    # gnt-backup list --nodes node1 --nodes node2

REMOVE

~~~~~~

**remove** {instance_name}

Removes the backup for the given instance name, if any. If the backup

was for a deleted instance, it is needed to pass the FQDN of the

instance, and not only the short hostname.

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