doc: update documentation of "promote_command" and "service_promote_command"

The documentation implied it would override "promote_command", which is
not the case.

"promote_command" is used by repmgrd to execute "repmgr standby promote"
(either directly or via a custom script).

"service_promote_command" can be set to specify a package-level service
command to promote the local PostgreSQL instance from standby to primary,
e.g. Debian's pg_ctlcluster. If set, this will be executed by "repmgr standby promote".

Also update code comments to clarify usage.

Related to GitHub #473.
This commit is contained in:
Ian Barwick
2018-07-16 14:40:04 +09:00
parent 69782cf703
commit 63242e2277
4 changed files with 52 additions and 22 deletions

View File

@@ -50,10 +50,18 @@
<note>
<para>
It's also possible to specify a <varname>service_promote_command</varname>;
this overrides any value contained in the setting <varname>promote_command</varname>.
It's also possible to specify a <varname>service_promote_command</varname>.
This is intended for systems which provide a package-level promote command,
such as Debian's <application>pg_ctlcluster</application>.
such as Debian's <application>pg_ctlcluster</application>, to promote the
PostgreSQL from standby to primary.
</para>
<para>
If your packaging system does not provide such a command, it can be left empty,
and &repmgr; will generate the appropriate `pg_ctl ... promote` command.
</para>
<para>
Do not confuse this with <varname>promote_command</varname>, which is used
by <application>repmgrd</application> to execute <xref linkend="repmgr-standby-promote">.
</para>
</note>

View File

@@ -34,6 +34,25 @@
the <ulink url="https://www.postgresql.org/docs/current/static/runtime-config-client.html#GUC-SHARED-PRELOAD-LIBRARIES">PostgreSQL documentation</ulink>.
</para>
<para>
To apply configuration file changes to a running <application>repmgrd</application>
daemon, execute the operating system's r<application>repmgrd</application> service reload command
(see <xref linkend="appendix-packages"> for examples),
or for instances which were manually started, execute <command>kill -HUP</command>, e.g.
<command>kill -HUP `cat /tmp/repmgrd.pid`</command>.
</para>
<note>
<para>
Check the <application>repmgrd</application> log to see what changes were
applied, or if any issues were encountered when reloading the configuration.
</para>
</note>
<para>
Note that only a subset of configuration file parameters can be changed on a
running <application>repmgrd</application> daemon.
</para>
<sect2 id="repmgrd-automatic-failover-configuration">
<title>automatic failover configuration</title>
<para>
@@ -162,13 +181,6 @@
repmgrd -f /etc/repmgr.conf --pid-file /tmp/repmgrd.pid</programlisting>
and stopped with <command>kill `cat /tmp/repmgrd.pid`</command>. Adjust paths as appropriate.
</para>
<para>
To apply configuration file changes to a running <application>repmgrd</application>
daemon, execute the operating system's service reload command (for manually started
instances, execute <command>kill -HUP `cat /tmp/repmgrd.pid`</command>).
Note that only a subset of configuration file parameters can be changed on a
running <application>repmgrd</application> daemon.
</para>
<sect2 id="repmgrd-pid-file" xreflabel="repmgrd's PID file">
<indexterm>

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@@ -280,11 +280,11 @@ ssh_options='-q -o ConnectTimeout=10' # Options to append to "ssh"
# primary (or other upstream node)
#reconnect_interval=10 # Interval between attempts to reconnect to an unreachable
# primary (or other upstream node)
#promote_command= # command to execute when promoting a new primary; use something like:
#promote_command= # command repmgrd executes when promoting a new primary; use something like:
#
# repmgr standby promote -f /etc/repmgr.conf
#
#follow_command= # command to execute when instructing a standby to follow a new primary;
#follow_command= # command repmgrd executes when instructing a standby to follow a new primary;
# use something like:
#
# repmgr standby follow -f /etc/repmgr.conf -W --upstream-node-id=%n
@@ -338,11 +338,11 @@ ssh_options='-q -o ConnectTimeout=10' # Options to append to "ssh"
#service_stop_command = ''
#service_restart_command = ''
#service_reload_command = ''
#service_promote_command = '' # Note: this overrides any value contained in the setting
# "promote_command". This is intended for systems which
# provide a package-level promote command, such as Debian's
# "pg_ctlcluster"
#service_promote_command = '' # This parameter is intended for systems which provide a
# package-level promote command, such as Debian's
# "pg_ctlcluster". *IMPORTANT*: it is *not* a substitute
# for "promote_command"; do not use "repmgr standby promote"
# (or a script which executes "repmgr standby promote") here.
#------------------------------------------------------------------------------
# Status check thresholds

View File

@@ -162,8 +162,8 @@ do_physical_node_check(void)
if (config_file_options.failover == FAILOVER_AUTOMATIC)
{
/*
* check that promote/follow commands are defined, otherwise repmgrd
* won't be able to perform any useful action
* Check that "promote_command" and "follow_command" are defined, otherwise repmgrd
* won't be able to perform any useful action in a failover situation.
*/
bool required_param_missing = false;
@@ -175,14 +175,24 @@ do_physical_node_check(void)
if (config_file_options.service_promote_command[0] != '\0')
{
/*
* if repmgrd executes "service_promote_command" directly,
* repmgr metadata won't get updated
* "service_promote_command" is *not* a substitute for "promote_command";
* it is intended for use in those systems (e.g. Debian) where there's a service
* level promote command (e.g. pg_ctlcluster).
*
* "promote_command" should either execute "repmgr standby promote" directly, or
* a script which executes "repmgr standby promote". This is essential, as the
* repmgr metadata is updated by "repmgr standby promote".
*
* "service_promote_command", if set, will be executed by "repmgr standby promote",
* but never by repmgrd.
*
*/
log_hint(_("\"service_promote_command\" is set, but can only be executed by \"repmgr standby promote\""));
}
required_param_missing = true;
}
if (config_file_options.follow_command[0] == '\0')
{
log_error(_("\"follow_command\" must be defined in the configuration file"));
@@ -2063,7 +2073,7 @@ promote_self(void)
return FAILOVER_STATE_PROMOTION_FAILED;
}
/* the presence of either of this command has been established already */
/* the presence of this command has been established already */
promote_command = config_file_options.promote_command;
log_debug("promote command is:\n \"%s\"",