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repmgr/doc/upgrading-repmgr.sgml
Ian Barwick db3a046393 doc: expand upgrade documentation
Include section about using pg_upgrade
2018-01-25 10:48:24 +09:00

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<chapter id="upgrading-repmgr" xreflabel="Upgrading repmgr">
<indexterm>
<primary>upgrading</primary>
</indexterm>
<title>Upgrading repmgr</title>
<para>
&repmgr; is updated regularly with point releases (e.g. 4.0.1 to 4.0.2)
containing bugfixes and other minor improvements. Any substantial new
functionality will be included in a feature release (e.g. 4.0.x to 4.1.x).
</para>
<sect1 id="upgrading-repmgr-extension" xreflabel="Upgrading repmgr 4.x and later">
<indexterm>
<primary>upgrading</primary>
<secondary>repmgr 4.x and later</secondary>
</indexterm>
<title>Upgrading repmgr 4.x and later</title>
<para>
&repmgr; 4.x is implemented as a PostgreSQL extension; normally the upgrade consists
of the two following steps:
<orderedlist>
<listitem>
<simpara>
Install the updated package (or compile the updated source)
</simpara>
</listitem>
<listitem>
<simpara>
In the database where the &repmgr; extension is installed, execute
<command>ALTER EXTENSION repmgr UPDATE</command>.
</simpara>
</listitem>
</orderedlist>
</para>
<para>
Always check the <link linkend="appendix-release-notes">release notes</link> for every
release as they may contain upgrade instructions particular to individual versions.
</para>
<para>
If the <application>repmgrd</application> daemon is in use, we recommend stopping it
before upgrading &repmgr;.
</para>
<para>
Note that it may be necessary to restart the PostgreSQL server if the upgrade contains
changes to the shared object file used by <application>repmgrd</application>; check the
release notes for details.
</para>
</sect1>
<sect1 id="upgrading-and-pg-upgrade" xreflabel="pg_upgrade and repmgr">
<indexterm>
<primary>upgrading</primary>
<secondary>pg_upgrade</secondary>
</indexterm>
<indexterm>
<primary>pg_upgrade</primary>
</indexterm>
<title>pg_upgrade and repmgr</title>
<para>
<application>pg_upgrade</application> requires that if any functions are
dependent on a shared library, this library must be present in both
the old and new installations before <application>pg_upgrade</application>
can be executed.
</para>
<para>
To minimize the risk of any upgrade issues (particularly if an upgrade to
a new major &repmgr; version is involved), we recommend upgrading
&repmgr; on the old server <emphasis>before</emphasis> running
<application>pg_upgrade</application> to ensure that old and new
versions are the same.
</para>
<note>
<simpara>
This issue applies to any PostgreSQL extension which has
dependencies on a shared library.
</simpara>
</note>
<para>
For further details please see the <ulink url="https://www.postgresql.org/docs/current/static/pgupgrade.html">pg_upgrade documentation</ulink>.
</para>
</sect1>
<sect1 id="upgrading-from-repmgr-3" xreflabel="Upgrading from repmgr 3.x">
<indexterm>
<primary>upgrading</primary>
<secondary>from repmgr 3.x</secondary>
</indexterm>
<title>Upgrading from repmgr 3.x</title>
<para>
The upgrade process consists of two steps:
<orderedlist>
<listitem>
<simpara>
converting the repmgr.conf configuration files
</simpara>
</listitem>
<listitem>
<simpara>
upgrading the repmgr schema
</simpara>
</listitem>
</orderedlist>
</para>
<para>
A script is provided to assist with converting <filename>repmgr.conf</filename>.
</para>
<para>
The schema upgrade (which converts the &repmgr; metadata into
a packaged PostgreSQL extension) is normally carried out
automatically when the &repmgr; extension is created.
</para>
<sect2 id="converting-repmgr-conf">
<title>Converting repmgr.conf configuration files</title>
<para>
With a completely new repmgr version, we've taken the opportunity
to rename some configuration items have had their names changed for
clarity and consistency, both between the configuration file and
the column names in <structname>repmgr.nodes</structname>
(e.g. <varname>node</varname> to <varname>node_id</varname>), and
also for consistency with PostgreSQL naming conventions
(e.g. <varname>loglevel</varname> to <varname>log_level</varname>).
</para>
<para>
Other configuration items have been changed to command line options,
and vice-versa, e.g. to avoid hard-coding items such as a a node's
upstream ID, which might change over time.
</para>
<para>
&repmgr; will issue a warning about deprecated/altered options.
</para>
<sect3>
<title>Changed parameters in "repmgr.conf"</title>
<para>
Following parameters have been added:
<itemizedlist spacing="compact" mark="bullet">
<listitem>
<simpara><varname>data_directory</varname>: this is mandatory and must
contain the path to the node's data directory</simpara>
</listitem>
<listitem>
<simpara><varname>monitoring_history</varname>: this replaces the
<application>repmgrd</application> command line option
<literal>--monitoring-history</literal></simpara>
</listitem>
</itemizedlist>
</para>
<para>
Following parameters have been renamed:
</para>
<table tocentry="1" id="repmgr3-repmgr4-renamed-parameters">
<title>Parameters renamed in repmgr4</title>
<tgroup cols="2">
<thead>
<row>
<entry>repmgr3</entry>
<entry>repmgr4</entry>
</row>
</thead>
<tbody>
<row>
<entry><varname>node</varname></entry>
<entry><varname>node_id</varname></entry>
</row>
<row>
<entry><varname>loglevel</varname></entry>
<entry><varname>log_level</varname></entry>
</row>
<row>
<entry><varname>logfacility</varname></entry>
<entry><varname>log_facility</varname></entry>
</row>
<row>
<entry><varname>logfile</varname></entry>
<entry><varname>log_file</varname></entry>
</row>
<row>
<entry><varname>barman_server</varname></entry>
<entry><varname>barman_host</varname></entry>
</row>
<row>
<entry><varname>master_reponse_timeout</varname></entry>
<entry><varname>async_query_timeout</varname></entry>
</row>
</tbody>
</tgroup>
</table>
<note>
<para>
From &repmgr; 4, <literal>barman_server</literal> refers
to the server configured in Barman (in &repmgr; 3, the deprecated
<literal>cluster</literal> parameter was used for this);
the physical Barman hostname is configured with
<literal>barman_host</literal> (see <xref linkend="cloning-from-barman-prerequisites">
for details).
</para>
</note>
<para>
Following parameters have been removed:
<itemizedlist spacing="compact" mark="bullet">
<listitem>
<simpara><varname>cluster</varname>: is no longer required and will
be ignored.</simpara>
</listitem>
<listitem>
<simpara><varname>upstream_node</varname>: is replaced by the
command-line parameter <literal>--upstream-node-id</literal></simpara>
</listitem>
</itemizedlist>
</para>
</sect3>
<sect3>
<title>Conversion script</title>
<para>
To assist with conversion of <filename>repmgr.conf</filename> files, a Perl script
is provided in <filename>contrib/convert-config.pl</filename>.
Use like this:
<programlisting>
$ ./convert-config.pl /etc/repmgr.conf
node_id=2
node_name=node2
conninfo=host=node2 dbname=repmgr user=repmgr connect_timeout=2
pg_ctl_options='-l /var/log/postgres/startup.log'
rsync_options=--exclude=postgresql.local.conf --archive
log_level=INFO
pg_basebackup_options=--no-slot
data_directory=</programlisting>
</para>
<para>
The converted file is printed to <literal>STDOUT</literal> and the original file is not
changed.
</para>
<para>
Please note that the the conversion script will add an empty
placeholder parameter for <varname>data_directory</varname>, which
is a required parameter in repmgr4 and which <emphasis>must</emphasis>
be provided.
</para>
</sect3>
</sect2>
<sect2>
<title>Upgrading the repmgr schema</title>
<para>
Ensure <application>repmgrd</application> is not running, or any cron jobs which execute the
<command>repmgr</command> binary.
</para>
<para>
Install <literal>repmgr 4</literal> packages; any <literal>repmgr 3.x</literal> packages
should be uninstalled (if not automatically uninstalled already by your packaging system).
</para>
<sect3>
<title>Upgrading from repmgr 3.1.1 or earlier</title>
<para>
If your repmgr version is 3.1.1 or earlier, you will need to update
the schema to the latest version in the 3.x series (3.3.2) before
converting the installation to repmgr 4.
</para>
<para>
To do this, apply the following upgrade scripts as appropriate for
your current version:
<itemizedlist spacing="compact" mark="bullet">
<listitem>
<simpara>
<ulink url="https://raw.githubusercontent.com/2ndQuadrant/repmgr/REL3_3_STABLE/sql/repmgr3.0_repmgr3.1.sql">repmgr3.0_repmgr3.1.sql</ulink></simpara>
</listitem>
<listitem>
<simpara><ulink url="https://raw.githubusercontent.com/2ndQuadrant/repmgr/REL3_3_STABLE/sql/repmgr3.1.1_repmgr3.1.2.sql">repmgr3.1.1_repmgr3.1.2.sql</ulink></simpara>
</listitem>
</itemizedlist>
</para>
<para>
For more details see the
<ulink url="https://repmgr.org/release-notes-3.3.2.html#upgrading">repmgr 3 upgrade notes</ulink>.
</para>
</sect3>
<sect3>
<title>Manually create the repmgr extension</title>
<para>
In the database used by the existing &repmgr; installation, execute:
<programlisting>
CREATE EXTENSION repmgr FROM unpackaged;</programlisting>
</para>
<para>
This will move and convert all objects from the existing schema
into the new, standard <literal>repmgr</literal> schema.
</para>
<note>
<simpara>there must be only one schema matching <literal>repmgr_%</literal> in the
database, otherwise this step may not work.
</simpara>
</note>
</sect3>
<sect3>
<title>Re-register each node</title>
<para>
This is necessary to update the <literal>repmgr</literal> metadata with some additional items.
</para>
<para>
On the primary node, execute e.g.
<programlisting>
repmgr primary register -f /etc/repmgr.conf --force</programlisting>
</para>
<para>
On each standby node, execute e.g.
<programlisting>
repmgr standby register -f /etc/repmgr.conf --force</programlisting>
</para>
<para>
Check the data is updated as expected by examining the <structname>repmgr.nodes</structname>
table; restart <application>repmgrd</application> if required.
</para>
<para>
The original <literal>repmgr_$cluster</literal> schema can be dropped at any time.
</para>
<tip>
<simpara>
If you don't care about any data from the existing &repmgr; installation,
(e.g. the contents of the <structname>events</structname> and <structname>monitoring</structname>
tables), the manual <command>CREATE EXTENSION</command> step can be skipped; just re-register
each node, starting with the primary node, and the <literal>repmgr</literal> extension will be
automatically created.
</simpara>
</tip>
</sect3>
</sect2>
</sect1>
</chapter>