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repmgr/doc/repmgr-cluster-crosscheck.sgml
Ian Barwick 409eb47e2a doc: convert documentation to DocBook XML
This brings the repmgr documentation build system in line with that
used by the main PostgreSQL project, and removed the restriction
that documentation must be built against PostgreSQL 9.6 or earlier.

Main formatting changes are:

 - convert empty-element tags (mainly <xref/>)
 - put <indexterm> sections in the correct location
 - correct usage of various entities.
2019-05-09 16:24:21 +09:00

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<refentry id="repmgr-cluster-crosscheck">
<indexterm>
<primary>repmgr cluster crosscheck</primary>
</indexterm>
<refmeta>
<refentrytitle>repmgr cluster crosscheck</refentrytitle>
</refmeta>
<refnamediv>
<refname>repmgr cluster crosscheck</refname>
<refpurpose>cross-checks connections between each combination of nodes</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<para>
<command>repmgr cluster crosscheck</command> is similar to <xref linkend="repmgr-cluster-matrix"/>,
but cross-checks connections between each combination of nodes. In "Example 3" in
<xref linkend="repmgr-cluster-matrix"/> we have no information about the state of <literal>node3</literal>.
However by running <command>repmgr cluster crosscheck</command> it's possible to get a better
overview of the cluster situation:
<programlisting>
$ repmgr -f /etc/repmgr.conf cluster crosscheck
Name | Id | 1 | 2 | 3
-------+----+----+----+----
node1 | 1 | * | * | x
node2 | 2 | * | * | *
node3 | 3 | * | * | *</programlisting>
</para>
<para>
What happened is that <command>repmgr cluster crosscheck</command> merged its own
<command><link linkend="repmgr-cluster-matrix">repmgr cluster matrix</link></command> with the
<command>repmgr cluster matrix</command> output from <literal>node2</literal>; the latter is
able to connect to <literal>node3</literal>
and therefore determine the state of outbound connections from that node.
</para>
</refsect1>
<refsect1>
<title>Exit codes</title>
<para>
One of the following exit codes will be emitted by <command>repmgr cluster crosscheck</command>:
</para>
<variablelist>
<varlistentry>
<term><option>SUCCESS (0)</option></term>
<listitem>
<para>
The check completed successfully and all nodes are reachable.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>ERR_BAD_SSH (12)</option></term>
<listitem>
<para>
One or more nodes could not be accessed via SSH.
</para>
<note>
<simpara>
This only applies to nodes unreachable from the node where
this command is executed.
</simpara>
<simpara>
It's also possible that the crosscheck establishes that
connections between PostgreSQL on all nodes are functioning,
even if SSH access between some nodes is not possible.
</simpara>
</note>
</listitem>
</varlistentry>
<varlistentry>
<term><option>ERR_NODE_STATUS (25)</option></term>
<listitem>
<para>
PostgreSQL on one or more nodes could not be reached.
</para>
<note>
<simpara>
This error code overrides <option>ERR_BAD_SSH</option>.
</simpara>
</note>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>