We have a --downstream option to check for attached nodes, but it
would be useful to have a corresponding --upstream option too.
A following patch will adapt the behaviour of this option when executed
on the primary node.
This is mainly useful for the --data-directory-config option, which
requires permission to read pg_settings to verify that the data
directory configured in "repmgr.conf" matches the data directory
actually in use.
If pg_settings read permission is not available, repmgr will fall
back to a simple check that the data directory configured in
"repmgr.conf" is a valid PostgreSQL directory. This is not entirely
foolproof, as it's possible PostgreSQL could be using a different
data directory.
In a few places, replication connections are generated from the
parameters used by existing connections. This has resulted in a
number of similar blocks of code which do more-or-less the same
thing almost but not quite identically. In two cases, the code
omitted to set "dbname=replication", which can cause problems
in some contexts.
These code blocks have now been consolidated into standardized
functions.
This also resolves the issue addressed by GitHub #619.
Within a PostgreSQL data directory, all files should have the same
ownership as the data directory itself. PostgreSQL itself expects
this, and ownership of files by another user is likely to cause
problems.
In PostgreSQL 11 or earlier, if "recovery.conf" cannot be moved
by PostgreSQL (because e.g. it is owned by root), it will not be
possible to promote the standby to primary.
In PostgreSQL 12 and later, if "postgresql.auto.conf" on the demotion
candidate (current primary) has incorrect ownership (e.g. owned by
root), repmgr will very likely not be able to modify this file and
write the replication configuration required for the node to rejoin
the cluster as a standby.
Checks added to catch both cases before a switchover is executed.
This is for backbranches to prevent them running against newer
PostgreSQL versions with which they are not compatible, for example
4.4.x with PostgreSQL 12 and later.
Make the code previously only used by "standby follow" generally
available - we'll want to use this from "node rejoin" as well.
While we're at it, when reporting failure due to lack of free
replication slots, report the current value of "max_replication_slots".
Enable operations which create or drop replication slots to be carried
out with the minimum necessary user permissions, i.e. a user with the
REPLICATION attribute.
This can be the repmgr user, or a dedicated replication user.
In the latter case, if the dedicated replication user is only
permitted to make replication connections, the streaming
replication protocol is used to create/drop slots.
Implements part of GitHub #536.
Append "_sql" to the respective function names, as we'll later be
creating equivalent functions which use the replication protocol
so need a way to distinguish between them.
A more generic option name to cover pre- and post-Pg12 replication
configuration methods.
--recovery-conf-only is retained as an alias for backwards
compatibility.
This makes it possible to return log output when executing repmgr
remotely at a different level to the one defined in the remote
repmgr's repmgr.conf.
This is particularly useful when DEBUG output is required.
"repmgr daemon" can be interpreted to mean the commands affect the local
daemon process only. Rename the commands which affect the entire cluster
to "repmgr service ...".
The "repmgr daemon ..." form of the affected commands is retained for backwards
compatibility.
The following options have long since been deprecated, and any attempt
to use them results only in a warning that they are no longer valid:
--data-dir
--no-conninfo-password
--recovery-min-apply-delay
When showing node information, check if the node's copy of its
record shows a different upstream to the one expected according
to the node where the command is executed.
This helps visualise situations where the cluster is in an
unexpected state, and provide a better idea of the actual state.
For example, if a cluster has divided somehow and a set of nodes are
following a new primary, when running "cluster show" etc., repmgr
will now show the name of the primary those nodes are actually
following, rather than the now outdated node name recorded
on the other side of the split. A warning will also be issued
about the situation.
In "recovery.conf", the configuration parameter "node_name" is used
as the "application_name" value, which will be truncated by PostgreSQL
to 63 characters (NAMEDATALEN - 1).
repmgr sometimes needs to be able to extract the application name from
pg_stat_replication to determine if a node is connected (e.g. when
executing "repmgr standby register"), so the comparison will fail
if "node_name" exceeds 63 characters.
