</para>
<sect2>
- <title>Ganeti Terminology</title>
+
+ <title>Ganeti terminology</title>
<para>This section provides a small introduction to Ganeti terminology,
which might be useful to read the rest of the document.
- <variablelist>
- <varlistentry>
- <term>Cluster</term>
- <listitem><para>A set of machines (nodes) that cooperate to offer a
- coherent highly available virtualization service.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term>Node</term>
- <listitem><para>A physical machine which is member of a cluster.
- Nodes are the basic cluster infrastructure, and are not fault
- tolerant.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term>Master Node</term>
- <listitem><para>The node which controls the Cluster, from which all
- Ganeti commands must be given.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term>Instance</term>
- <listitem><para>A virtual machine which runs on a cluster. It can be
- a fault tolerant highly available entity.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term>Pool</term>
- <listitem><para>A pool is a set of clusters sharing the same
- network.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term>Meta-Cluster</term>
- <listitem><para>Anything that concerns more than one
- cluster.</para></listitem>
- </varlistentry>
-
- </variablelist>
+ <glosslist>
+ <glossentry>
+ <glossterm>Cluster</glossterm>
+ <glossdef>
+ <simpara>
+ A set of machines (nodes) that cooperate to offer a
+ coherent highly available virtualization service.
+ </simpara>
+ </glossdef>
+ </glossentry>
+ <glossentry>
+ <glossterm>Node</glossterm>
+ <glossdef>
+ <simpara>
+ A physical machine which is member of a cluster.
+ Nodes are the basic cluster infrastructure, and are
+ not fault tolerant.
+ </simpara>
+ </glossdef>
+ </glossentry>
+ <glossentry>
+ <glossterm>Master node</glossterm>
+ <glossdef>
+ <simpara>
+ The node which controls the Cluster, from which all
+ Ganeti commands must be given.
+ </simpara>
+ </glossdef>
+ </glossentry>
+ <glossentry>
+ <glossterm>Instance</glossterm>
+ <glossdef>
+ <simpara>
+ A virtual machine which runs on a cluster. It can be a
+ fault tolerant highly available entity.
+ </simpara>
+ </glossdef>
+ </glossentry>
+ <glossentry>
+ <glossterm>Pool</glossterm>
+ <glossdef>
+ <simpara>
+ A pool is a set of clusters sharing the same network.
+ </simpara>
+ </glossdef>
+ </glossentry>
+ <glossentry>
+ <glossterm>Meta-Cluster</glossterm>
+ <glossdef>
+ <simpara>
+ Anything that concerns more than one cluster.
+ </simpara>
+ </glossdef>
+ </glossentry>
+ </glosslist>
</para>
</sect2>
<sect2>
<title>Prerequisites</title>
- <para>You need to have your Ganeti cluster installed and configured
- before you try any of the commands in this document. Please follow the
- "installing tutorial" for instructions on how to do that.
+ <para>
+ You need to have your Ganeti cluster installed and configured
+ before you try any of the commands in this document. Please
+ follow the <emphasis>Ganeti installation tutorial</emphasis>
+ for instructions on how to do that.
</para>
</sect2>
<sect2>
<title>Adding/Removing an instance</title>
- <para>Adding a new virtual instance to your Ganeti cluster is really
- easy. The command is:
- <programlisting>
-gnt-instance add -n TARGET_NODE -o OS_TYPE -t DISK_TEMPLATE INSTANCE_NAME
- </programlisting>
- The instance name must exist in dns and of course map to an address in
- the same subnet as the cluster itself. Options you can give to this
- command include:
+ <para>
+ Adding a new virtual instance to your Ganeti cluster is really
+ easy. The command is:
+
+ <synopsis>gnt-instance add -n <replaceable>TARGET_NODE</replaceable> -o <replaceable>OS_TYPE</replaceable> -t <replaceable>DISK_TEMPLATE</replaceable> <replaceable>INSTANCE_NAME</replaceable></synopsis>
+
+ The instance name must be resolvable (e.g. exist in DNS) and
+ of course map to an address in the same subnet as the cluster
+ itself. Options you can give to this command include:
+
<itemizedlist>
<listitem>
- <simpara>The disk size (-s)</simpara>
+ <simpara>The disk size (<option>-s</option>)</simpara>
</listitem>
<listitem>
- <simpara>The swap size (--swap-size)</simpara>
+ <simpara>The swap size (<option>--swap-size</option>)</simpara>
</listitem>
<listitem>
- <simpara>The memory size (-m)</simpara>
+ <simpara>The memory size (<option>-m</option>)</simpara>
</listitem>
<listitem>
- <simpara>The number of virtual CPUs (-p)</simpara>
+ <simpara>The number of virtual CPUs (<option>-p</option>)</simpara>
</listitem>
<listitem>
- <simpara>The instance ip address (-i) (use -i auto to make Ganeti
- record the address from dns)</simpara>
+ <simpara>The instance ip address (<option>-i</option>) (use
+ the value <literal>auto</literal> to make Ganeti record the
+ address from dns)</simpara>
</listitem>
<listitem>
- <simpara>The bridge to connect the instance to (-b), if you don't
- want to use the default one</simpara>
+ <simpara>The bridge to connect the instance to
+ (<option>-b</option>), if you don't want to use the default
+ one</simpara>
</listitem>
</itemizedlist>
</para>
- <para>There are four types of disk template you can choose from:
+ <para>There are four types of disk template you can choose from:</para>
<variablelist>
<varlistentry>
<varlistentry>
<term>remote_raid1</term>
- <listitem><para>A mirror is set between the local node and a remote
- one, which must be specified with the --secondary-node option. Use
- this option to obtain a highly available instance that can be failed
- over to a remote node should the primary one fail.
- </para></listitem>
+ <listitem>
+ <simpara><emphasis role="strong">Note:</emphasis> This is
+ only valid for multi-node clusters.</simpara>
+ <simpara>
+ A mirror is set between the local node and a remote
+ one, which must be specified with the --secondary-node
+ option. Use this option to obtain a highly available
+ instance that can be failed over to a remote node
+ should the primary one fail.
+ </simpara>
+ </listitem>
</varlistentry>
</variablelist>
- For example if you want to create an highly available instance use the
- remote_raid1 disk template:
- <programlisting>
-gnt-instance add -n TARGET_NODE -o OS_TYPE -t remote_raid1 \
- --secondary-node=SECONDARY_NODE INSTANCE_NAME
- </programlisting>
- To know which operating systems your cluster supports you can use:
- <programlisting>
-gnt-os list
- </programlisting>
+ <para>
+ For example if you want to create an highly available instance
+ use the remote_raid1 disk template:
+ <synopsis>gnt-instance add -n <replaceable>TARGET_NODE</replaceable> -o <replaceable>OS_TYPE</replaceable> -t remote_raid1 \
+ --secondary-node=<replaceable>SECONDARY_NODE</replaceable> <replaceable>INSTANCE_NAME</replaceable></synopsis>
+
+ <para>
+ To know which operating systems your cluster supports you can use:
+
+ <synopsis>gnt-os list</synopsis>
+
</para>
<para>
- Removing an instance is even easier than creating one. This operation is
- non-reversible and destroys all the contents of your instance. Use with
- care:
- <programlisting>
-gnt-instance remove INSTANCE_NAME
- </programlisting>
+ Removing an instance is even easier than creating one. This
+ operation is non-reversible and destroys all the contents of
+ your instance. Use with care:
+
+ <synopsis>gnt-instance remove <replaceable>INSTANCE_NAME</replaceable></synopsis>
+
</para>
</sect2>
<sect2>
<title>Starting/Stopping an instance</title>
- <para>Instances are automatically started at instance creation time. To
- manually start one which is currently stopped you can run:
- <programlisting>
-gnt-instance startup INSTANCE_NAME
- </programlisting>
- While the command to stop one is:
- <programlisting>
-gnt-instance shutdown INSTANCE_NAME
- </programlisting>
- The command to see all the instances configured and their status is:
- <programlisting>
-gnt-instance list
- </programlisting>
+ <para>
+ Instances are automatically started at instance creation
+ time. To manually start one which is currently stopped you can
+ run:
+
+ <synopsis>gnt-instance startup <replaceable>INSTANCE_NAME</replaceable></synopsis>
+
+ While the command to stop one is:
+
+ <synopsis>gnt-instance shutdown <replaceable>INSTANCE_NAME</replaceable></synopsis>
+
+ The command to see all the instances configured and their
+ status is:
+
+ <synopsis>gnt-instance list</synopsis>
+
</para>
- <para>Do not use the xen commands to stop instances. If you run for
- example xm shutdown or xm destroy on an instance Ganeti will
- automatically restart it (via the
- <citerefentry><refentrytitle>ganeti-watcher</refentrytitle>
- <manvolnum>8</manvolnum></citerefentry>)
+ <para>
+ Do not use the xen commands to stop instances. If you run for
+ example xm shutdown or xm destroy on an instance Ganeti will
+ automatically restart it (via the
+ <citerefentry><refentrytitle>ganeti-watcher</refentrytitle>
+ <manvolnum>8</manvolnum></citerefentry>)
</para>
</sect2>
<sect2>
<title>Exporting/Importing an instance</title>
- <para>You can create a snapshot of an instance disk and Ganeti
- configuration, which then you can backup, or import into another cluster.
- The way to export an instance is:
- <programlisting>
-gnt-backup export -n TARGET_NODE INSTANCE_NAME
- </programlisting>
- The target node can be any node in the cluster with enough space under
- /srv/ganeti to hold the instance image. Use the --noshutdown option to
- snapshot an instance without rebooting it. Any previous snapshot of the
- same instance existing cluster-wide under /srv/ganeti will be removed by
- this operation: if you want to keep them move them out of the Ganeti
- exports directory.
+ <para>
+ You can create a snapshot of an instance disk and Ganeti
+ configuration, which then you can backup, or import into
+ another cluster. The way to export an instance is:
+
+ <synopsis>gnt-backup export -n <replaceable>TARGET_NODE</replaceable> <replaceable>INSTANCE_NAME</replaceable></synopsis>
+
+ The target node can be any node in the cluster with enough
+ space under <filename class="directory">/srv/ganeti</filename>
+ to hold the instance image. Use the
+ <option>--noshutdown</option> option to snapshot an instance
+ without rebooting it. Any previous snapshot of the same
+ instance existing cluster-wide under <filename
+ class="directory">/srv/ganeti</filename> will be removed by
+ this operation: if you want to keep them move them out of the
+ Ganeti exports directory.
</para>
- <para>Importing an instance is as easy as creating a new one. The command
- is:
- <programlisting>
-gnt-backup import -n TRGT_NODE -t DISK_TMPL --src-node=NODE --src-dir=DIR INST_NAME
- </programlisting>
- Most of the options available for gnt-instance add are supported here
- too.
+ <para>
+ Importing an instance is similar to creating a new one. The
+ command is:
+
+ <synopsis>gnt-backup import -n <replaceable>TARGET_NODE</replaceable> -t <replaceable>DISK_TEMPLATE</replaceable> --src-node=<replaceable>NODE</replaceable> --src-dir=DIR INSTANCE_NAME</synopsis>
+
+ Most of the options available for the command
+ <emphasis>gnt-instance add</emphasis> are supported here too.
+
</para>
</sect2>
<sect1>
<title>High availability features</title>
+ <note>
+ <simpara>This section only applies to multi-node clusters.</simpara>
+ </note>
+
<sect2>
<title>Failing over an instance</title>
- <para>If an instance is built in highly available mode you can at any
- time fail it over to its secondary node, even if the primary has somehow
- failed and it's not up anymore. Doing it is really easy, on the master
- node you can just run:
- <programlisting>
-gnt-instance failover INSTANCE_NAME
- </programlisting>
- That's it. After the command completes the secondary node is now the
- primary, and vice versa.
+ <para>
+ If an instance is built in highly available mode you can at
+ any time fail it over to its secondary node, even if the
+ primary has somehow failed and it's not up anymore. Doing it
+ is really easy, on the master node you can just run:
+
+ <synopsis>gnt-instance failover <replaceable>INSTANCE_NAME</replaceable></synopsis>
+
+ That's it. After the command completes the secondary node is
+ now the primary, and vice versa.
</para>
</sect2>
+
<sect2>
<title>Replacing an instance disks</title>
- <para>So what if instead the secondary node for an instance has failed,
- or you plan to remove a node from your cluster, and you failed over all
- its instances, but it's still secondary for some? The solution here is to
- replace the instance disks, changing the secondary node:
- <programlisting>
-gnt-instance replace-disks -n NEW_SECONDARY INSTANCE_NAME
- </programlisting>
- This process is a bit longer, but involves no instance downtime, and at
- the end of it the instance has changed its secondary node, to which it
- can if necessary be failed over.
+ <para>
+ So what if instead the secondary node for an instance has
+ failed, or you plan to remove a node from your cluster, and
+ you failed over all its instances, but it's still secondary
+ for some? The solution here is to replace the instance disks,
+ changing the secondary node:
+
+ <synopsis>gnt-instance replace-disks -n <replaceable>NEW_SECONDARY</replaceable> <replaceable>INSTANCE_NAME</replaceable></synopsis>
+
+ This process is a bit longer, but involves no instance
+ downtime, and at the end of it the instance has changed its
+ secondary node, to which it can if necessary be failed over.
</para>
</sect2>
<sect2>
<title>Failing over the master node</title>
- <para>This is all good as long as the Ganeti Master Node is up. Should it
- go down, or should you wish to decommission it, just run on any other node
- the command:
- <programlisting>
-gnt-cluster masterfailover
- </programlisting>
- and the node you ran it on is now the new master.
+ <para>
+ This is all good as long as the Ganeti Master Node is
+ up. Should it go down, or should you wish to decommission it,
+ just run on any other node the command:
+
+ <synopsis>gnt-cluster masterfailover</synopsis>
+
+ and the node you ran it on is now the new master.
</para>
</sect2>
<sect2>
<title>Adding/Removing nodes</title>
- <para>And of course, now that you know how to move instances around, it's
- easy to free up a node, and then you can remove it from the cluster:
- <programlisting>
-gnt-node remove NODE_NAME
- </programlisting>
- and maybe add a new one:
- <programlisting>
-gnt-node add [--secondary-ip=ADDRESS] NODE_NAME
- </programlisting>
+ <para>
+ And of course, now that you know how to move instances around,
+ it's easy to free up a node, and then you can remove it from
+ the cluster:
+
+ <synopsis>
+gnt-node remove <replaceable>NODE_NAME</replaceable>
+ </synopsis>
+
+ and maybe add a new one:
+
+ <synopsis>
+gnt-node add <optional><option>--secondary-ip=<replaceable>ADDRESS</replaceable></option></optional> <replaceable>NODE_NAME</replaceable>
+
+ </synopsis>
</para>
</sect2>
</sect1>
<sect1>
<title>Debugging Features</title>
- <para>At some point you might need to do some debugging operations on your
- cluster or on your instances. This section will help you with the most used
- debugging functionalities.
+ <para>
+ At some point you might need to do some debugging operations on
+ your cluster or on your instances. This section will help you
+ with the most used debugging functionalities.
</para>
<sect2>
<title>Accessing an instance's disks</title>
- <para>From an instance's primary node you have access to its disks. Never
- ever mount the underlying logical volume manually on a fault tolerant
- instance, though or you risk breaking replication. The correct way to
- access them is to run the command:
- <programlisting>
-gnt-instance activate-disks INSTANCE_NAME
- </programlisting>
- And then access the device that gets created. Of course after you've
- finished you can deactivate them with the deactivate-disks command, which
- works in the same way.
+ <para>
+ From an instance's primary node you have access to its
+ disks. Never ever mount the underlying logical volume manually
+ on a fault tolerant instance, or you risk breaking
+ replication. The correct way to access them is to run the
+ command:
+
+ <synopsis> gnt-instance activate-disks <replaceable>INSTANCE_NAME</replaceable></synopsis>
+
+ And then access the device that gets created. After you've
+ finished you can deactivate them with the deactivate-disks
+ command, which works in the same way.
</para>
</sect2>
<sect2>
<title>Accessing an instance's console</title>
- <para>The command to access a running instance's console is:
- <programlisting>
-gnt-instance console INSTANCE_NAME
- </programlisting>
- Use the console normally and then type ^] when done, to exit.
+ <para>
+ The command to access a running instance's console is:
+
+ <synopsis>gnt-instance console <replaceable>INSTANCE_NAME</replaceable></synopsis>
+
+ Use the console normally and then type
+ <userinput>^]</userinput> when done, to exit.
</para>
</sect2>
<sect2>
<title>Instance Operating System Debugging</title>
- <para>Should you have any problems with operating systems support the
- command to ran to see a complete status for all your nodes is:
- <programlisting>
-gnt-os diagnose
- </programlisting>
+ <para>
+ Should you have any problems with operating systems support
+ the command to ran to see a complete status for all your nodes
+ is:
+
+ <synopsis>gnt-os diagnose</synopsis>
+
</para>
</sect2>
<sect2>
<title>Cluster-wide debugging</title>
- <para>The gnt-cluster command offers several options to run tests or
- execute cluster-wide operations. For example:
- <programlisting>
+ <para>
+ The gnt-cluster command offers several options to run tests or
+ execute cluster-wide operations. For example:
+
+ <screen>
gnt-cluster command
gnt-cluster copyfile
gnt-cluster verify
gnt-cluster getmaster
gnt-cluster version
- </programlisting>
- See the respective help to know more about their usage.
+ </screen>
+
+ See the man page <citerefentry>
+ <refentrytitle>gnt-cluster</refentrytitle>
+ <manvolnum>8</manvolnum> </citerefentry> to know more about
+ their usage.
</para>
</sect2>
projects / ganeti-local / commitdiff