Synnefo » snf-ganeti » ganeti-local

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  <!ENTITY dhdate      "<date>February 11, 2009</date>">

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  <!ENTITY dhucpackage "<refentrytitle>gnt-backup</refentrytitle>">

  <!ENTITY dhpackage   "gnt-backup">

  <!ENTITY debian      "<productname>Debian</productname>">

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<refentry>

  <refentryinfo>

    <copyright>

      <year>2007</year>

      <year>2008</year>

      <year>2009</year>

      <year>2010</year>

      <holder>Google Inc.</holder>

    </copyright>

    &dhdate;

  </refentryinfo>

  <refmeta>

    &dhucpackage;

    &dhsection;

    <refmiscinfo>ganeti 2.1</refmiscinfo>

  </refmeta>

  <refnamediv>

    <refname>&dhpackage;</refname>

    <refpurpose>ganeti instance import/export</refpurpose>

  </refnamediv>

  <refsynopsisdiv>

    <cmdsynopsis>

      <command>&dhpackage; </command>

      <arg choice="req">command</arg>

      <arg>arguments...</arg>

    </cmdsynopsis>

  </refsynopsisdiv>

  <refsect1>

    <title>DESCRIPTION</title>

    <para>

      The <command>&dhpackage;</command> is used for importing and exporting

      instances and their configuration from a ganeti system. It is useful for

      backing instances up and also to migrate them between clusters.

    </para>

  </refsect1>

  <refsect1>

    <title>COMMANDS</title>

    <refsect2>

      <title>EXPORT</title>

      <cmdsynopsis>

        <command>export</command>

        <arg choice="req">-n <replaceable>node</replaceable></arg>

        <arg>--shutdown-timeout=<replaceable>N</replaceable></arg>

        <arg>--noshutdown</arg>

        <arg choice="req"><replaceable>instance</replaceable></arg>

      </cmdsynopsis>

      <para>

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

        and its configuration will be exported under the

        /srv/ganeti/export/<replaceable>instance</replaceable>

        directory on the target node.

      </para>

      <para>

        The <option>--shutdown-timeout</option> 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.

      </para>

      <para>

        The <option>--noshutdown</option> 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.

      </para>

      <para>

        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.

      </para>

      <para>

        Example:

        <screen>

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

        </screen>

      </para>

    </refsect2>

    <refsect2>

      <title>IMPORT</title>

      <cmdsynopsis>

        <command>import</command>

        <sbr>

        <group choice="req">

          <arg>-n <replaceable>node<optional>:secondary-node</optional></replaceable></arg> <arg>--iallocator

          <replaceable>name</replaceable></arg>

        </group>

        <sbr>

        <arg rep="repeat">--disk <replaceable>N</replaceable>:size=<replaceable>VAL</replaceable><arg>,mode=<replaceable>ro|rw</replaceable></arg></arg>

        <sbr>

        <group>

          <arg rep="repeat">--net <replaceable>N</replaceable><arg rep="repeat">:options</arg></arg>

          <arg>--no-nics</arg>

        </group>

        <sbr>

        <arg>-B <replaceable>BEPARAMS</replaceable></arg>

        <sbr>

        <arg>-H <replaceable>HYPERVISOR</replaceable><arg>:<arg choice="plain" rep="repeat">option=<replaceable>value</replaceable></arg></arg></arg>

        <sbr>

        <arg>--src-node=<replaceable>source-node</replaceable></arg>

        <arg>--src-dir=<replaceable>source-dir</replaceable></arg>

        <sbr>

        <arg choice="opt">-t<group>

            <arg>diskless</arg>

            <arg>plain</arg>

            <arg>drbd</arg>

            <arg>file</arg>

          </group></arg>

        <sbr>

        <arg choice="opt">--identify-defaults</arg>

        <sbr>

        <arg choice="req"><replaceable>instance</replaceable></arg>

      </cmdsynopsis>

      <para>

        Imports a new instance from an export residing on

        <replaceable>source-node</replaceable> in

        <replaceable>source-dir</replaceable>.

        <replaceable>instance</replaceable> 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

        <command>list</command> command.

      </para>

      <para>

        The <option>disk</option> 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

        <literal>m</literal>, <literal>g</literal> or

        <literal>t</literal> to specificy the exact the units used;

        these suffixes map to mebibytes, gibibytes and tebibytes.

      </para>

      <para>

        Alternatively, a single-disk instance can be created via the

        <option>-s</option> 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).

      </para>

      <para>

        If no disk information is passed, the disk configuration saved

        at export time will be used.

      </para>

      <para>

        The minimum disk specification is therefore empty (export

        information will be used), a single disk can be specified as

        <userinput>--disk 0:size=20G</userinput> (or <userinput>-s

          20G</userinput> when using the <option>-s</option> option),

        and a three-disk instance can be specified as

        <userinput>--disk 0:size=20G --disk 1:size=4G --disk

          2:size=100G</userinput>.

      </para>

      <para>

        The NICs of the instances can be specified via the

        <option>--net</option> option. By default, the NIC

        configuration of the original (exported) instance will be

        reused. Each NIC can take up to three parameters (all

        optional):

        <variablelist>

          <varlistentry>

            <term>mac</term>

            <listitem>

              <simpara>either a value or <constant>GENERATE</constant>

              to generate a new unique MAC, or

              <constant>AUTO</constant> to reuse the old MAC</simpara>

            </listitem>

          </varlistentry>

          <varlistentry>

            <term>ip</term>

            <listitem>

              <simpara>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)</simpara>

            </listitem>

          </varlistentry>

            <varlistentry>

              <term>mode</term>

              <listitem>

                <simpara>specifies the connection mode for this nic:

                  routed or bridged.</simpara>

              </listitem>

            </varlistentry>

            <varlistentry>

              <term>link</term>

              <listitem>

                <simpara>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, see gnt-cluster(8) for more details)</simpara>

              </listitem>

            </varlistentry>

          </variablelist>

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

          default at cluster level.

      </para>

      <para>

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

        single empty NIC and delete it afterwards

        via <command>gnt-instance modify --net delete</command>.

      </para>

      <para>

        The <option>-B</option> option specifies the backend

        parameters for the instance. If no such parameters are

        specified, the values are inherited from the export. Possible

        parameters are:

        <variablelist>

          <varlistentry>

            <term>memory</term>

            <listitem>

              <simpara>the memory size of the instance; as usual,

              suffixes can be used to denote the unit, otherwise the

              value is taken in mebibites</simpara>

            </listitem>

          </varlistentry>

          <varlistentry>

            <term>vcpus</term>

            <listitem>

              <simpara>the number of VCPUs to assign to the instance

              (if this value makes sense for the hypervisor)</simpara>

            </listitem>

          </varlistentry>

          <varlistentry>

            <term>auto_balance</term>

            <listitem>

              <simpara>whether the instance is considered in the N+1

              cluster checks (enough redundancy in the cluster to

              survive a node failure)</simpara>

            </listitem>

          </varlistentry>

        </variablelist>

      </para>

      <para>

        The <option>-t</option> options specifies the disk layout type

        for the instance. If not passed, the configuration of the

        original instance is used. The available choices are:

        <variablelist>

          <varlistentry>

            <term>diskless</term>

            <listitem>

              <para>

                This creates an instance with no disks. Its useful for

                testing only (or other special cases).

              </para>

            </listitem>

          </varlistentry>

          <varlistentry>

            <term>plain</term>

            <listitem>

              <para>Disk devices will be logical volumes.</para>

            </listitem>

          </varlistentry>

          <varlistentry>

            <term>drbd</term>

            <listitem>

              <para>

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

                volumes.

              </para>

            </listitem>

          </varlistentry>

          <varlistentry>

            <term>file</term>

            <listitem>

              <para>Disk devices will be backed up by files, under the

              <filename

              class="directory">@RPL_FILE_STORAGE_DIR@</filename>. 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.</para>

            </listitem>

          </varlistentry>

        </variablelist>

      </para>

      <para>

        The <option>--iallocator</option> 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 <option>-n</option> option. For more information please

        refer to the instance allocator documentation.

      </para>

      <para>

        The optional second value of the <option>--node</option> is used for

        the drbd template and specifies the remote node.

      </para>

      <para>

        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 <option>--identify-defaults</option> option. This will

        affect the hypervisor, backend and NIC parameters, both read

        from the export file and passed in via the command line.

      </para>

      <para>

        Example for identical instance import:

        <screen>

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

        </screen>

      </para>

      <para>

        Explicit configuration example:

        <screen>

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

> -n node1.example.com \

> instance3.example.com

        </screen>

      </para>

    </refsect2>

    <refsect2>

      <title>LIST</title>

      <cmdsynopsis>

        <command>list</command>

        <arg>--node=<replaceable>NODE</replaceable></arg>

      </cmdsynopsis>

      <para>

        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 <option>--node</option>

        option (which can be used multiple times)

      </para>

      <para>

      Example:

<screen>

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

</screen>

      </para>

    </refsect2>

    <refsect2>

      <title>REMOVE</title>

      <cmdsynopsis>

        <command>remove</command>

        <arg choice="req">instance_name</arg>

      </cmdsynopsis>

      <para>

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

        backup was for a deleted instances, it is needed to pass the

        <acronym>FQDN</acronym> of the instance, and not only the

        short hostname.

      </para>

    </refsect2>

  </refsect1>

  &footer;

</refentry>

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