Although such situation should not happen in reality (follow method is
not supposed to be called when when the node is holding leader lock and
postgres is running), but to be on the safe side it is better to
implement as much checks as possible, because this method could
potentially remove data directory.
rewind is not possible when:
1) trying to rewind from themself
2) leader is not reachable
3) leader is_in_recovery
All these cases were leading to removing of data directory...
In all cases except 1) it should "retry" when leader will became
available and not is_in_recovery.
In addition for that make pg_ctl --timeout option configurable.
If the stop or start didn't succeeded during given timeout when demoting
master, role will be forcibly changed to 'unknown' and all needed
callbacks executed.
It was causing patroni failing to stop after receiving SIGTERM.
Acceptance tests was killing it with SIGKILL which was causing further tests fail because postgres was still running:
2016-06-16 14:36:24,444 INFO: no action. i am the leader with the lock
2016-06-16 14:36:25,448 INFO: Lock owner: postgres0; I am postgres0
2016-06-16 14:36:25,452 ERROR: Failed to update /service/batman/optime/leader
Traceback (most recent call last):
File "/home/akukushkin/git/patroni/patroni/dcs/zookeeper.py", line 208, in write_leader_optime
self._client.retry(self._client.set, path, last_operation)
File "/home/akukushkin/git/patroni/py2/local/lib/python2.7/site-packages/kazoo/client.py", line 273, in _retry
return self._retry.copy()(*args, **kwargs)
File "/home/akukushkin/git/patroni/py2/local/lib/python2.7/site-packages/kazoo/retry.py", line 123, in __call__
return func(*args, **kwargs)
File "/home/akukushkin/git/patroni/py2/local/lib/python2.7/site-packages/kazoo/client.py", line 1219, in set
return self.set_async(path, value, version).get()
File "/home/akukushkin/git/patroni/py2/local/lib/python2.7/site-packages/kazoo/handlers/utils.py", line 74, in get
self._condition.wait(timeout)
File "/usr/lib/python2.7/threading.py", line 340, in wait
waiter.acquire()
File "/home/akukushkin/git/patroni/patroni/utils.py", line 219, in sigterm_handler
sys.exit()
SystemExit
2016-06-16 14:36:25,453 INFO: no action. i am the leader with the lock
2016-06-16 14:36:26,443 INFO: Lock owner: postgres0; I am postgres0
2016-06-16 14:36:26,444 INFO: no action. i am the leader with the lock
These parameters usually must be the same across all cluster nodes and
therefore must be set only via global configuration and always passed as
a list of postgres arguments (via pg_ctl) to make it not possible
accidentally change them by 'ALTER SYSTEM'
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.
And some other tricks with overriding handle_one_request and finish
methods from the parent class which were necessary only to make OPTIONS
request from haproxy work with python2, but in fact it was still not
working with python3. Instead of doing all the magic we should simply
give to haproxy what it wants to get: HTTP response code and nothing
more.
where it is not necessary (test_ha, test_ctl, etc...)
It will simplyfy further refactoring and make it possible to install
implementations of AbstractDCS independant of each other.
Alexander Kukushkin