loop_wait and ttl is configured cluster-wide via config key stored in
DCS. Depending on values of these parameters we are configuring
different kind of timeouts used in DCS controllers.
In order to fetch this configuration we first need to create DCS
controller and only after apply parameters...
Instead of empying the stale failover key as a master and bailing
out, continue with the healthiest node evaluation. This should make
the actual master acquire the leader key faster. Emit the warning
message as well and add unit tests.
When a node to promote dies before finishing the promote and the
cluster is in a standby mode, the failover key sticks indefinitely,
preventing any master to take over the leader role. Prevent it by
letting the node in a master role cleanup the failover key if the
node to failover is not present among the members.
The master check cannot be performed by the node role alone, since
the node will not change its cached role on a manual promote. We
need to check the DB state as well.
PostgreSQL replication slot names only allow names consisting of [a-z0-9_].
Invalid characters cause replication slot creation and standby startup to fail.
This change substitutes the invalid characters with underscores or unicode
codepoints. In case multiple member names map to identical replication slots
master log will contain a corresponding error message.
Motivated by wanting to use hostnames as member names. Hostnames often
contain periods and dashes.
When observing the leader running a master role, set the cached role
stored in the state_handler to master as well. Failure to do so
resulted in the manually promoted node to continue running with a
cached 'replica' role. This led to the failure to create replication
slots for the new replicas.
We could do it conditionally, but both reading and writing the role
require the same lock, and the unconditional approach makes the unit
tests simpler.
Any node of the cluster will maintain it's member key until Patroni is
running there.
Master node will also maintain the leader key until postgres is running
as a master. If there is not postgres or it is running 'in_recovery',
Patroni will release leader lock.
Bootstrap of a new cluster will work (it is possible to specify
paused: true) in the `bootstrap.dcs`. Replicas also will be able to join
the cluster if the leader lock exist.
If the postgres is not running on the node it will not try to bring it
up. Also it disables reinitialize and all kind of scheduled actions, i.e.
scheduled restart and scheduled failover.
In case if DCS stops being reachable Patroni will not "demote" master if
the automatic failover was disabled.
Patroni will not stop postgres on exit.
Master tried to delete all slots that did not correspond to the
replica registered in Patroni. That produced an error for the slots
that were active, potentially preventing drop and creation of other
slots.
Reported by Murat Kabilov.
The v1.0 has been released more than one month ago and the new version
is coming. It doesn't make a lot of sense to keep configuration files in
the old format anymore.
In addition to that I've also commented out all the lines enabling and
configuring "archiving" to avoid incidents like here:
https://github.com/zalando/patroni/issues/264
Alexander Kukushkin