Immediately after the demotion candidate (primary) has shut down, we can't
be absolutely sure that the walreceiver has flushed all WAL to disk, so
checking pg_last_wal_receive_lsn() at that point might not reflect
the actual last available WAL location.
To handle this, we'll loop for a while (timeout controlled by configuration
parameter "wal_receive_check_timeout") before finally deciding whether
the standby is still behind the shut-down primary.
Addresses issue raised in GitHub #518.
This is to facilitate remote invocation of repmgr when the repmgr
binary is located somewhere other than the PostgreSQL binary directory, as it
cannot be assumed all package maintainers will install repmgr there.
This parameter is optional; if not set (the default), repmgr will fall back
to "pg_bindir" (if set).
Addresses GitHub #246.
Previously, "repmgr standby switchover" used the configuration file parameters
"reconnect_interval" and "reconnect_attempts" to define a timeout to determine
whether the current primary (demotion candidate) has shut down.
However, these parameters are intended for primary failure detection and are
generally lower in value, while a controlled shutdown may take longer, resulting
in the switchover being aborted as repmgr was not waiting long enough.
To prevent this happening, parameter "shutdown_check_timeout" has been added.
This complements the existing "standby_reconnect_timeout" parameter used
by "repmgr standby switchover".
Implements GitHub #504.
This matches the behaviour of other PostgreSQL utilities such as psql, though
repmgr will only abort once all command line options are parsed, so as many
errors as possible are found and displayed. If a repmgr "command" (e.g.
"repmgr primary ..." was provided, a hint about the relevant command
help section (e.g. "repmgr primary --help") will be provided alongside
the generic help command (i.e. "repmgr --help").
Addresses GitHub #464, with further improvements.
It's hard to imagine a use case where this isn't desirable, but
in case, for whatever reason, the user does not wish to daemonize the
process, the command line option "--daemonize=false" can be provided.
Implements GitHub #458.
Traditionally repmgrd will only write a pidfile if explicitly requested with
-p/--pid-file. However it's normally desirable to have a pidfile, and it's
preferable to have one used by default to prevent accidentally starting a second
repmgrd instance.
Following changes made:
- add configuration file parameter "repmgrd_pid_file" (initially overridden by
-p/--pid-file for backwards compatibility, though eventually we'll want to
drop -p/--pid-file altogether)
- add command line option --no-pid-file
- if neither "repmgrd_pid_file" nor -p/--pid-file is set, create the pid file
in a temporary directory
Implements GitHub #457.
Currently the (very generic sounding) "standby_reconnect_timeout" configuration
file parameter is used in several different contexts and it would be useful
to have more granular control over the different timeouts it's used to configure.
This patch introduces "node_rejoin_timeout", used in place of "standby_reconnect_timeout"
(which wasn't documented) when "repmgr node rejoin" is executed, to determine
how long to wait for the node to rejoin the replication cluster.
Additionally "repmgrd_standby_startup_timeout" is introduced as a timeout for
failover situations, when repmgrd executes "repmgr standby follow" to follow
a new primary, and waits for the standby to restart and become available
for connections.
"standby_reconnect_timeout" is now only relevant for "repmgr standby switchover".
Implements GitHub #454.
After restarting the standby, poll pg_stat_replication on the upstream
until the standby connects, and exit with an error if it doesn't by the
timeout defined in "standby_follow_timeout".
Implments GitHub #444.
This enables explicit provision of an external configuration file
directory, which if set will be passed to "pg_ctl" as the -D
parameter. Otherwise "pg_ctl" will default to using the data directory,
which will cause some operations to fail if the configuration files
are not present there.
Note this is implemented primarily for feature completeness and for
development/testing purposes. Users who have installed "repmgr" from
a package should not rely on "pg_ctl" to stop/start/restart PostgreSQL,
instead they should set the appropriate "service_..._command" for their
operating system. For more details see:
https://repmgr.org/docs/4.0/configuration-service-commands.html
Note: in a future release, the presence of "config_directory" in repmgr.conf
will be used to implictly set "--copy-external-config-files=samepath" when
cloning a standby; this is a behaviour change so will be implemented in the
next major realease (repmgr 4.1).
Implements GitHub #424.
If "archive_cleanup_command" is defined in "repmgr.conf", a corresponding
entry will be made in the node's "recovery.conf" file after cloning a
standby.
Note that we recommend using PgBarman to manage WAL archives, but are
providing this facility to help repmgr to be integrated in existing environments.
Implements GitHub #416.
This introduces following new configuration file parameters, which
were previously hard-coded values:
- promote_check_timeout
- promote_check_interval
Implements GitHub #387.
This is used for determining a timeout when reconnecting to the standby
after executing the "follow_command". This will normally not need to be
set explicitly, but maybe useful in cases where the standby's startup
phase can last longer than usual.
When executing repmgr on remote nodes, we otherwise end up jumping
through hoops as we can't make assumptions about where the configuration
file is located, but really need to be able to provide it.
From a support point of view it will also make life easier as it will
be easy to specify exactly which file to provide.
If the current primary (demotion candidate) still has any files to archive,
it will delay the shutdown until all files are archived. If there is a
substantial number of files, and/or the archive command executes slowly,
this will probably lead to an unwelcome delay in the switchover process.
The repmgr3 implementation required the promotion candidate (standby)
to directly work with the demotion candidate's data directory,
directly execute server control commands etc.
Here we delegated a lot more of that work to the repmgr on the
demotion candidate, which reduces the amount of back-and-forth
over SSH and generally makes things cleaner and smoother.
In particular the repmgr on the demotion candidate will carry
out a thorough check that the node is shut down and report
the last checkpoint LSN to the promotion candidate; this
can then be used to determine whether pg_rewind needs to be
executed on the demoted primary before reintegrating it back
into the cluster (todo).
Also implement "--dry-run" for this action, which will sanity-check the
nodes as far as possible without executing the switchover.
Additionally some of the new repmgr node commands (or command options)
introduced for this can be also executed by the user to obtain
additional information about the status of each node.
There are some circumstances, e.g. during switchover operations,
where repmgr may need to operate on a data directory while the
server isn't running, in which case there's no way to retrieve
that information.
Also add configuration file option "pgdata" for hard-coding the
node's data directory - if the "repmgr" DB user isn't a superuser
or doesn't have permission to extract the data directory, we'll
need another way of finding out.
In previous versions of repmgr, some options had ambiguous meanings,
and/or were used for slightly different purposes. This way we end
up with a couple more options (most of which probably won't need
adjusting) but greater clarity and flexibility.
Removed:
master_reponse_timeout:
renamed to "async_query_timeout", as this was its main usage
retry_promote_interval_secs:
replaced by "primary_notification_timeout"
Added:
async_query_timeout:
timeout (in seconds) when executing asynchronous queries
primary_notification_timeout:
number of seconds to wait for notification from the new primary
after a failover
primary_follow_timeout:
number of seconds to wait for the new primary to become available
when executing "repmgr standby follow"
