Files
repmgr/doc/repmgr-cluster-show.xml
Ian Barwick 4d4ed3bcd6 Remove BDR 2.x support
The BDR 2.x support was conceptual only and was never used in
production. As BDR 2.x will be EOL'd shortly, there is no risk it will
be needed.
2020-01-16 09:52:42 +09:00

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<refentry id="repmgr-cluster-show">
<indexterm>
<primary>repmgr cluster show</primary>
</indexterm>
<refmeta>
<refentrytitle>repmgr cluster show</refentrytitle>
</refmeta>
<refnamediv>
<refname>repmgr cluster show</refname>
<refpurpose>display information about each registered node in the replication cluster</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<para>
Displays information about each registered node in the replication cluster. This
command polls each registered server and shows its role (<literal>primary</literal> /
<literal>standby</literal>) and status. It polls each server
directly and can be run on any node in the cluster; this is also useful when analyzing
connectivity from a particular node.
</para>
<para>
For PostgreSQL 9.6 and later, the output will also contain the node's current timeline ID.
</para>
<para>
Node availability is tested by connecting from the node where
<command>repmgr cluster show</command> is executed, and does not necessarily imply the node
is down. See <xref linkend="repmgr-cluster-matrix"/> and <xref linkend="repmgr-cluster-crosscheck"/> to get
better overviews of connections between nodes.
</para>
</refsect1>
<refsect1>
<title>Execution</title>
<para>
This command requires either a valid <filename>repmgr.conf</filename> file or a database
connection string to one of the registered nodes; no additional arguments are needed.
</para>
<para>
To show database connection errors when polling nodes, run the command in
<literal>--verbose</literal> mode.
</para>
</refsect1>
<refsect1>
<title>Example</title>
<para>
<programlisting>
$ repmgr -f /etc/repmgr.conf cluster show
ID | Name | Role | Status | Upstream | Location | Priority | Timeline | Connection string
----+-------+---------+-----------+----------+----------+----------+-----------------------------------------
1 | node1 | primary | * running | | default | 100 | 1 | host=db_node1 dbname=repmgr user=repmgr
2 | node2 | standby | running | node1 | default | 100 | 1 | host=db_node2 dbname=repmgr user=repmgr
3 | node3 | standby | running | node1 | default | 100 | 1 | host=db_node3 dbname=repmgr user=repmgr</programlisting>
</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>
The column <literal>Role</literal> shows the expected server role according to the
&repmgr; metadata.
</para>
<para>
<literal>Status</literal> shows whether the server is running or unreachable.
If the node has an unexpected role not reflected in the &repmgr; metadata, e.g. a node was manually
promoted to primary, this will be highlighted with an exclamation mark.
If a connection to the node cannot be made, this will be highlighted with a question mark.
Note that the node will only be shown as <literal>? unreachable</literal>
if a connection is not possible at network level; if the PostgreSQL instance on the
node is pingable but not accepting connections, it will be shown as <literal>? running</literal>.
</para>
<para>
In the following example, executed on <literal>node3</literal>, <literal>node1</literal> is not reachable
at network level and assumed to be down; <literal>node2</literal> has been promoted to primary
(but <literal>node3</literal> is not attached to it, and its metadata has not yet been updated);
<literal>node4</literal> is running but rejecting connections (from <literal>node3</literal> at least).
<programlisting>
ID | Name | Role | Status | Upstream | Location | Priority | Connection string
----+-------+---------+----------------------+----------+----------+----------+-----------------------------------------
1 | node1 | primary | ? unreachable | | default | 100 | host=db_node1 dbname=repmgr user=repmgr
2 | node2 | standby | ! running as primary | node1 | default | 100 | host=db_node2 dbname=repmgr user=repmgr
3 | node3 | standby | running | node1 | default | 100 | host=db_node3 dbname=repmgr user=repmgr
4 | node4 | standby | ? running | node1 | default | 100 | host=db_node4 dbname=repmgr user=repmgr
WARNING: following issues were detected
- unable to connect to node "node1" (ID: 1)
- node "node1" (ID: 1) is registered as an active primary but is unreachable
- node "node2" (ID: 2) is registered as standby but running as primary
- unable to connect to node "node4" (ID: 4)
HINT: execute with --verbose option to see connection error messages</programlisting>
</para>
<para>
To diagnose connection issues, execute <command>repmgr cluster show</command>
with the <option>--verbose</option> option; this will display the error message
for each failed connection attempt.
</para>
<tip>
<para>
Use <xref linkend="repmgr-cluster-matrix"/> and <xref linkend="repmgr-cluster-crosscheck"/>
to diagnose connection issues across the whole replication cluster.
</para>
</tip>
</refsect1>
<refsect1>
<title>Options</title>
<variablelist>
<varlistentry>
<term><option>--csv</option></term>
<listitem>
<para>
<command>repmgr cluster show</command> accepts an optional parameter <literal>--csv</literal>, which
outputs the replication cluster's status in a simple CSV format, suitable for
parsing by scripts, e.g.:
<programlisting>
$ repmgr -f /etc/repmgr.conf cluster show --csv
1,-1,-1
2,0,0
3,0,1</programlisting>
</para>
<para>
The columns have following meanings:
<itemizedlist spacing="compact" mark="bullet">
<listitem>
<simpara>
node ID
</simpara>
</listitem>
<listitem>
<simpara>
availability (0 = available, -1 = unavailable)
</simpara>
</listitem>
<listitem>
<simpara>
recovery state (0 = not in recovery, 1 = in recovery, -1 = unknown)
</simpara>
</listitem>
</itemizedlist>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--compact</option></term>
<listitem>
<para>
Suppress display of the <literal>conninfo</literal> column.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--terse</option></term>
<listitem>
<para>
Suppress warnings about connection issues.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--verbose</option></term>
<listitem>
<para>
Display the full text of any database connection error messages
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Exit codes</title>
<para>
One of the following exit codes will be emitted by <command>repmgr cluster show</command>:
</para>
<variablelist>
<varlistentry>
<term><option>SUCCESS (0)</option></term>
<listitem>
<para>
No issues were detected.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>ERR_BAD_CONFIG (1)</option></term>
<listitem>
<para>
An issue was encountered while attempting to retrieve
&repmgr; metadata.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>ERR_DB_CONN (6)</option></term>
<listitem>
<para>
&repmgr; was unable to connect to the local PostgreSQL instance.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>ERR_NODE_STATUS (25)</option></term>
<listitem>
<para>
One or more issues were detected with the replication configuration,
e.g. a node was not in its expected state.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>See also</title>
<para>
<xref linkend="repmgr-node-status"/>, <xref linkend="repmgr-node-check"/>, <xref linkend="repmgr-service-status"/>
</para>
</refsect1>
</refentry>