doc: improve upgrade instructions

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Ian Barwick
2018-10-17 14:32:38 +09:00
parent 6311f3f30a
commit 2ded8987ac

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@@ -7,9 +7,9 @@
<title>Upgrading repmgr</title>
<para>
&repmgr; is updated regularly with point releases (e.g. 4.0.1 to 4.0.2)
&repmgr; is updated regularly with minor 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).
functionality will be included in a major release (e.g. 4.0 to 4.1).
</para>
<sect1 id="upgrading-repmgr-extension" xreflabel="Upgrading repmgr 4.x and later">
@@ -19,83 +19,110 @@
</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 following steps:
<orderedlist>
From version 4, &repmgr; consists of three elements:
<itemizedlist spacing="compact" mark="bullet">
<listitem>
<simpara>
Stop <application>repmgrd</application> (if in use) on all nodes where it is running
</simpara>
</listitem>
<listitem>
<simpara>
the <application>repmgr</application> and <application>repmgrd</application> executables
</simpara>
</listitem>
<listitem>
<simpara>
Install the updated package (or compile the updated source)
</simpara>
</listitem>
<listitem>
<simpara>
the objects for the &repmgr; PostgreSQL extension (SQL files for creating/updating
repmgr metadata, and the extension control file)
</simpara>
</listitem>
<listitem>
<simpara>
For major releases, e.g. from <literal>4.0.x</literal> to <literal>4.1</literal>,
where the <literal>repmgr</literal> shared object library has been updated,
restart PostgreSQL.
</simpara>
</listitem>
<listitem>
<simpara>
For major releases, e.g. from <literal>4.0.x</literal> to <literal>4.1</literal>,
execute <command>ALTER EXTENSION repmgr UPDATE</command>
on the primary node in the database where the &repmgr; extension is installed.
</simpara>
<simpara>
This will update the extension metadata and, if necessary, apply
changes to the &repmgr; extension objects.
</simpara>
</listitem>
<listitem>
<simpara>
Start <application>repmgrd</application> (if in use).
</simpara>
</listitem>
</orderedlist>
<listitem>
<simpara>
the shared library module used by <application>repmgrd</application> which
is resident in the PostgreSQL backend
</simpara>
</listitem>
</itemizedlist>
</para>
<para>
With <emphasis>minor releases</emphasis>, usually changes are only made to the <application>repmgr</application>
and <application>repmgrd</application> executables. In this case, the upgrade is quite straightforward,
and is simply a case of installing the new version, and restarting <application>repmgrd</application>
(if running).
</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.
For <emphasis>major releases</emphasis>, the &repmgr; PostgreSQL extension will need to be updated
to the latest version. Additionally, if the shared library module has been updated (this is sometimes,
but not always the case), PostgreSQL itself will need to be restarted on each node.
</para>
<important>
<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>
</important>
<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
<link linkend="appendix-release-notes">release notes</link> for details.
</para>
<sect2 id="upgrading-replication-cluster" xreflabel="Upgrading a replication cluster">
<sect2 id="upgrading-minor-version" xreflabel="Upgrading a minor version release">
<indexterm>
<primary>upgrading</primary>
<secondary>repmgr 4.x and later</secondary>
<secondary>minor release</secondary>
</indexterm>
<title>Upgrading a replication cluster</title>
<title>Upgrading a minor version release</title>
<para>
The process for installing minor version upgrades is quite straightforward:
<itemizedlist spacing="compact" mark="bullet">
<listitem>
<simpara>
install the new &repmgr; version
</simpara>
</listitem>
<listitem>
<simpara>
restart <application>repmgrd</application> on all nodes where it is running
</simpara>
</listitem>
</itemizedlist>
</para>
<note>
<para>
Some packaging systems (e.g. <link linkend="packages-debian-ubuntu">Debian/Ubuntu</link>
may restart <application>repmgrd</application> as part of the package upgrade process.
</para>
</note>
<para>
The same &repmgr; &quot;major version&quot; (e.g. <literal>4.2</literal>) must be
installed on all nodes in the replication cluster. While it's possible to have differing
&repmgr; &quot;minor versions&quot; (e.g. <literal>4.2.1</literal>) on different nodes,
we strongly recommend updating all nodes to the latest minor version.
Minor version upgrades can be performed in any order on the nodes in the replication
cluster.
</para>
<note>
<para>
A PostgreSQL restart is <emphasis>not</emphasis> required for minor version upgrades.
</para>
<note>
<para>
Minor version upgrades can be performed in any order on the nodes in the replicaiton
cluster. In general it makes sense to start on the primary.
The same &repmgr; &quot;major version&quot; (e.g. <literal>4.2</literal>) must be
installed on all nodes in the replication cluster. While it's possible to have differing
&repmgr; &quot;minor versions&quot; (e.g. <literal>4.2.1</literal>) on different nodes,
we strongly recommend updating all nodes to the latest minor version.
</para>
<para>
A PostgreSQL restart is <emphasis>not</emphasis> required for minor version upgrades.
</para>
</note>
</note>
</sect2>
<sect2 id="upgrading-major-version" xreflabel="Upgrading a major version release">
<indexterm>
<primary>upgrading</primary>
<secondary>major release</secondary>
</indexterm>
<title>Upgrading a major version release</title>
<para>
&quot;major version&quot; upgrades need to be planned more carefully, as they may include
changes to the &repmgr; metadata (which need to be propagated from the primary to all
@@ -111,7 +138,14 @@
<listitem>
<simpara>
Stop <application>repmgrd</application> (if in use) on all nodes where it is running
Stop <application>repmgrd</application> (if in use) on all nodes where it is running.
</simpara>
</listitem>
<listitem>
<simpara>
Disable the <application>repmgrd</application> service on all nodes where it is in use;
this is to prevent packages from prematurely restarting <application>repmgrd</application>.
</simpara>
</listitem>
@@ -121,12 +155,12 @@
</simpara>
</listitem>
<listitem>
<simpara>
If necessary, restart PostgreSQL, then <application>repmgrd</application> (if in use)
on each node. The order in which this is applied to individual nodes is not critical,
and it's also fine to restart on all nodes first before starting <application>repmgrd</application>.
If the &repmgr; shared library module has been updated (check the <link linkend="appendix-release-notes">release notes</link>!),
restart PostgreSQL, then <application>repmgrd</application> (if in use) on each node,
The order in which this is applied to individual nodes is not critical,
and it's also fine to restart PostgreSQL on all nodes first before starting <application>repmgrd</application>.
</simpara>
<simpara>
Note that if the upgrade requires a PostgreSQL restart, <application>repmgrd</application>
@@ -143,6 +177,12 @@
</para>
</listitem>
<listitem>
<simpara>
Reenable the <application>repmgrd</application> service on all nodes where it is in use.
</simpara>
</listitem>
</orderedlist>
</para>
<tip>
@@ -154,6 +194,17 @@
</tip>
</sect2>
<sect2 id="upgrading-check-repmgrd" xreflabel="Checking repmgrd status after an upgrade">
<indexterm>
<primary>upgrading</primary>
<secondary>checking repmgrd status</secondary>
</indexterm>
<title>Checking repmgrd status after an upgrade</title>
<para>
From &repmgr; 4.2, once the upgrade is complete, execute the <command><link linkend="repmgr-daemon-status">repmgr daemon status</link></command>
command (on any node) to show an overview of the status of <application>repmgrd</application> on all nodes.
</para>
</sect2>
</sect1>
<sect1 id="upgrading-and-pg-upgrade" xreflabel="pg_upgrade and repmgr">