Add RST version of gnt-backup man page

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: René Nussbaumer <rn@google.com>

man/gnt-backup.rst

+gnt-backup(8) Ganeti | Version @GANETI_VERSION@
+===============================================
+
+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
+/srv/ganeti/export/*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* [,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) 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:
+
+memory
+    the memory size of the instance; as usual, suffixes can be used to
+    denote the unit, otherwise the value is taken in mebibites
+
+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)
+
+
+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.
+
+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.