Originally Exhibitor was supported in the ZooKeeper class and
configuration for Exhibitor was taken also from `zookeeper` section in
the yaml config file. In fact, Exhibitor just extends ZooKeeper and now
it is reflected in the code and also Exhibitor got it's own section in
the config.yaml file. It will make it easier to configure Exhibitor
hosts and port via environment variables when PR#211 will be merged.
A Patroni configuration should be enough for Patronictl
The previous dcs_api url style is still supported.
To remove duplicate magic variables a DCS_DEFAULTS was introduced.
Some behaviour has changed: If you do not specify a DCS at all
(not in configuration, not on commandline, not in environment), it will
not default to etcd://localhost:4001
More test coverage for patronictl
Until now get_dcs method was doing absolutely the same job as method
from Patroni class.
In addition to that I did small refactoring and clean up of unit tests
In addition to that rename confusing `Etcd.client` and
`ZooKeeper.client` into `_client`. This attribute is available from
AbstractDCS and people had wrong impression that it provides the same
interface for different DCS implementations, which is obviously not the
case. For Etcd it has type etcd.Client and for ZooKeeper - KazooClient.
Scheduled failover allows scheduling of a failover in the future. It does this by writing
a failover key in the DCS which contains the scheduled failover time.
The reason to allow a scheduled failover, is that it does not require one to use a
scheduler (e.g. cron) to schedule such a failover. One of the issues with using
a scheduler is that it may need to authenticate itself. With scheduled failover the authentication
takes place during the scheduling, not during the actual failover.
To allow the time of failover to be expressed, the failover key has changed its format; the old format however
can still be used. The new format expects the failover key to be a json-document with relevant
keys set. We need the timestamp specified to be time zone aware and to be expressed unambigiously, e.g. ISO 8601.
For easier development using Docker the $HOSTNAME variable will be used to
name the running Patroni. Bumped some _segments postgresql settings to ensure
WAL files are not removed very quickly.
Increased the timeout for the post request for Patroni, as some operations
(failover) may take considerable time to complete.
The failover to a specific member was broken in patronictl as it used a wrong
key to specify the member to failover to.
Pretty printing fix for xlog lag, to prevent false negatives to show up and have
good alignment.
Some refactoring to reuse some codepaths.
A dsn option is now added, it is useful in scripts like so:
psql -d "$(patronictl dsn alpha)"
Restarting has been extended to allow restarting based on role.
Alexander Kukushkin