If list of checks is not specified, Consul will use "serfHealth" in addition to TTL based created by Patroni.
There are some cases when people want to sacrifice fast detection of network partitioning in favor of ability to tolerate network lags.
Fixes https://github.com/zalando/patroni/issues/522
When Patroni does calculation whether it should run pg_rewind or not, it relies on pg_controldata output or gets necessary information from replication connection.
On some cases (when for example postgres running as a master was killed), we can't use pg_controldata output immediately, but trying to start postgres. Such start could fail with the following errror:
```
LOG,00000,"ending log output to stderr",,"Future log output will go to log destination ""csvlog"".",,,,,,,""
LOG,00000,"database system was interrupted; last known up at 2017-09-16 22:35:22 UTC",,,,,,,,,""
LOG,00000,"restored log file ""00000006.history"" from archive",,,,,,,,,""
LOG,00000,"entering standby mode",,,,,,,,,"" 2017-09-18 08:00:39.433 UTC,,,57,,59bf7d26.39,4,,2017-09-18 08:00:38 UTC,,0,LOG,00000,"restored log file ""00000006.history"" from archive",,,,,,,,,""
FATAL,XX000,"requested timeline 6 is not a child of this server's history","Latest checkpoint is at 29/1A000178 on timeline 5, but in the history of the requested timeline, the server forked off from that timeline at 29/1A000140.",,,,,,,,""
LOG,00000,"startup process (PID 57) exited with exit code 1",,,,,,,,,""
LOG,00000,"aborting startup due to startup process failure",,,,,,,,,""
LOG,00000,"database system is shut down",,,,,,,,,""
```
In this case controldata will still have `Database cluster state: in production`
All further attempts to start postgres will fail. Such situation could be fixed only if we start not in recovery. For safety we will do it in a single user mode.
The second problems is: if postgres was running as master, but later we started it and stopped, than pg_controldata will report:
```
Database cluster state: shut down in recovery
Minimum recovery ending location: 0/0
Min recovery ending loc's timeline: 0
```
And this info can't be used for calculations. In this case we should use
`Latest checkpoint location` and `Latest checkpoint's TimeLineID`
in addition to that implement additional checks around manual failover and recover when synchronous_mode is enabled
* Comparison must be case insensitive
* Do not send keepalives if watchdog is not active
* Avoid activating watchdog in a pause mode
* Set correct postgres state in pause mode
* Don't try to run queries from API if postgres is stopped
* Short after promote synchronous replication was disabled even is synchronous_mode_strict is set
* Create empty pg_ident.conf if it is missing after restoring from backup
* Bump version
When updating config key we should use `ClusterConfig.index` instead of
`ClusterConfig.modify_index`. The second one should be used by Patroni
internally to check that key was really changed, because when key is
deleted and recreated it's version always starts from the same value: 0
In addition to that use patronictl instead of http PATCH in some of
acceptance tests to change cluster config.
Fixes https://github.com/zalando/patroni/issues/491
Originally fetch_nodes_statuses was returning a tuple, later it was
wrapped into namedtuple _MemberStatus and recently _MemberStatus was
extened with watchdog_failed field, but api.py was still relying on
usual tuple and checking failover limitations on it's own instead of
calling `failover_limitation` method.
It wasn't a big issue when on_start was called during normal boostrap
with initdb, because usually such process is very fast. But situation is
changing when we run custom bootstrap, becuase it might be a long time
between cluster become connectable and end of recovery and promote.
Actually situation was even worse than that, on_start was called with
the `replica` argument and later on_role_changes was never called,
because promote wasn't performed by Patroni.
As a solution for this problem we will block any callbacks during
bootstrap and explicitly call on_start after leader lock was taken.
Task of restoring a cluster from backup or cloning existing cluster into a new one was floating around for some time. It was kind of possible to achieve it by doing a lot of manual actions and very error prone. So I come up with the idea of making the way how we bootstrap a new cluster configurable.
In short - we want to run a custom script instead of running initdb.
So far Patroni was populating pg_hba.conf only when running bootstrap code and after that it was not very handy to manage it's content, because it was necessary to login to every node, change pg_hba.conf manually and run pg_ctl reload.
This commit intends to fix it and give Patroni control over pg_hba.conf. It is possible to define pg_hba.conf content via `postgresql.pg_hba` in the patroni configuration file or in the `DCS/config` (dynamic configuration).
If the `hba_file` is defined in the `postgresql.parameters`, Patroni will ignore `postgresql.pg_hba`.
For backward compatibility this feature is not enabled by default. To enable it you have to set `postgresql.use_unix_socket: true`.
If feature is enable, and `unix_socket_directories` is defined and non empty, Patroni will use the first suitable value from it to connect to the local postgres cluster.
If the `unix_socket_directories` is not defined, Patroni will assume that default value should be used and will not pass `host` to command line arguments and omit it from connection url.
Solves: https://github.com/zalando/patroni/issues/61
In addition to mentioned above, this commit solves couple of bugs:
* manual failover with pg_rewind in a pause state was broken
* psycopg2 (or libpq, I am not really sure what exactly) doesn't mark cursors connection as closed when we use unix socket and there is an `OperationalError` occurs. We will close such connection on our own.
because `boto.exception` is not an excpetion, but a python module.
+ increase retry timeout to 5 minutes
+ refactor unit-tests to cover the case with retries.
pg_controldata output depends on postgres major version and in some cases some of the parameters are prefixed by 'Current ' for old postgres versions.
Bug was introduced by commit 37c1552.
Fixes https://github.com/zalando/patroni/issues/455
Previously we were running pg_rewind only in limited amount of cases:
* when we knew postgres was a master (no recovery.conf in data dir)
* when we were doing a manual switchover to a specific node (no
guaranty that this node is the most up-to-date)
* when a given node has nofailover tag (it could be ahead of new master)
This approach was kind of working in most of the cases, but sometimes we
were executing pg_rewind when it was not necessary and in some other
cases we were not executing it although it was needed.
The main idea of this PR is first try to figure out that we really need
to run pg_rewind by analyzing timelineid, LSN and history file on master
and replica and run it only if it's needed.
This was causing patroni to exit with following exception:
2017-04-27 08:54:25,000 CRITICAL: system ID mismatch, node foo-0 belongs to a different cluster: 6347967071236960319 !=
2017-04-27 08:54:25,221 ERROR:
Traceback (most recent call last):
File "/usr/local/lib/python3.5/dist-packages/patroni/__init__.py", line 134, in patroni_main
patroni.run()
File "/usr/local/lib/python3.5/dist-packages/patroni/__init__.py", line 110, in run
logger.info(self.ha.run_cycle())
File "/usr/local/lib/python3.5/dist-packages/patroni/ha.py", line 946, in run_cycle
info = self._run_cycle()
File "/usr/local/lib/python3.5/dist-packages/patroni/ha.py", line 903, in _run_cycle
sys.exit(1)
SystemExit: 1
Default value of wal_sender_timeout is 60 seconds while we are trying to remove replication slot after 30 seconds (ttl=30). That means postgres might think that slot is still active and does nothing. Patroni at the same time was thinking that it was removed successfully.
If the drop replication slot query didn't return any single row we must fetch list of existing physical replication slots from postgres on the next iteration of HA loop.
Fixes: issue #425
`Postgresql.connection` method could be called from different threads at the same time resulting in more than one connection open but only one used afterwards.
* Reassemble postgresql parameters when major version became known
Otherwise we were writing some "unknown" parameters into postgresql.conf
and postgres was refusing to start. Only 9.3 was affected.
In addition to that move rename of wal_level from hot_standby to replica
into get_server_parameters method. Now this rename is handled in a
single place.
* Bump etcd and consul versions
Change hostnames by ip addresses was causing certificate verification to
fail. Instead of doing it we will better monkey patch urllib3
functionality which does name resolution. It should work without
problems even for https connection.
* Serialize callback execution.
If the previous callback is still running - kill it
Also it will fix a problem of zombie processes when executing callbacks
from the main thread.
* bugfix: pass an arguments to a callback
* Add https and auth support for etcd
Also implement support of PATRONI_ETCD_URL and PATRONI_ETCD_SRV
environment variables
* Implement etcd.proxy etcd.cacert, etcd.cert and etcd.key support
Now it should be possible to set up fully encrypted connection to etcd
with authorization.
starting from 9.6 we need wal_level = 'replica' which is alias for 'hot_standby'. It was working before without problems, but if somebody change wal_level to replica, Patroni will expose pending_restart flag, although restart in this case is not necessary.
* bump versions of consul and etcd to the latest for travis integration-tests
If Patroni was started in a docker with pid=1 it will execute itself
with the same arguments. The original process will take care about init
process duties, i.e. handle sigchld and reap dead orphan processes.
Also it will forward SIGINT, SIGHUP, SIGTERM and some other signals to
the real Patroni process.
Previously replicas were always watching for leader key (even if the
postgres was not in the running there). It was not a big issue, but it
was not possible to interrupt such watch in cases if the postgres
started up or stopped successfully. Also it was delaying update_member
call and we had kind of stale information in DCS up to `loop_wait`
seconds. This commit changes such behavior. If the async_executor is
busy by starting/stopping or restarting postgres we will not watch for
leader key but waiting for event from async_executor up to `loop_wait`
seconds. Async executor will fire such event only in case if the
function it was calling returned something what could be evaluated to
boolean True.
Such functionality is really needed to change the way how we are making
decision about necessity of pg_rewind. It will require to have a local
postgres running and for us it is really important to get such
notification as soon as possible.
* Replace pytz.UTC with dateutil.tz.tzutc, it helps to reduce memory by more than 4Mb...
* fix check of python version: 0x0300000 => 0x3000000
* Update leader key before restart and demote
It will make possible to start postgres easily with pg_ctl (without
Patroni). Previously if you tried to start such postgres manually
it was usually failing because some of the parameters does not much
with values written into xlog (for example max_connections).
..the same way as for etcd
Change HTTPClient implementation from using `requests.session` to
`urllib3.PoolManager`, because reference implementation from python-consul
didn't really worked with timeouts and was blocking HA loop...
If the Etcd node partitioned from rest of the cluster it is still
possible to read from it (though it returns some stale information),
but it is not possible to write into it.
Previously Patroni was trying to fetch the new cluster view from DCS in
order to figure out is it still the leader or not and Etcd is always
returning stale info where the node still owns the leader key, but with
negative TTL.
This weird bug clearly shows how dangerous premature optimization is.
We are doing number of attempts when trying to initialize replica using
different methods. Any of this attemp may create and put something into
data directory, what causes next attempts fail.
In addition to that improve logging when creating replica.
* reap children before and after running HA loop
When the Patroni is running in a docker container with the pid=1 it is
also responsible for reaping of all dead processes. We can't call
os.waitpid immediately after receiving SIGCHLD because it breaks
subprocess module. It simply stops receiving exit codes of the processes
it executes because these processes. That's why we just registering the
fact of receiving SIGCHLD and reaping children only after execution of
HA loop.
If the postmaster was dying for some reason, Patroni was able to detect
this fact only on the next iteration of HA loop, because zombie
processes where still there and it was possible to send 0 signal to it.
To avoid such situation we should also reap all dead processes before
executing HA loop.
* Don't rely on _cursor_holder when closing connection
it could happen that connection has been opened but not cursor...
* Don't "retry" when fetching current xlog location and it fails
On every iteration of HA loop we are updaing member key in DCS and among
other data there is current xlog location stored in the value.
If the postgres has died for some reason it is not possible to fetch
xlog position and we are just wasting retry_timeout/2 = 5 seconds there.
If this information will be missing from DCS during period of one HA
loop nothing should break. Patroni is not relying on this information
anyway. When it is doing manual or automatic failover it aways
communicates with other nodes directly to get the most fresh
infomation.
* Don't try to update leader optime when postgres is not 100% healthy
`update_lock` method is not only doing update of the leader lock but
also writes the most recent value of xlog position into optime/leader
key. If you know that postgres can be not 100% healthy because it is in
process of restart or recover we should not try to fetch current xlog
position and update 'optime/leader'. Previously we were using
`AsyncExecutor.busy` property for avoiding of such action, but I think
we should be more excpilicit and do the update only if we know that
postgres is 100% healty.
This error is send by etcd when Patroni is doing "watch" on leader key
which is never updated after creation and etcd cluster receives a lot of
updates, what cleans history of events.
Instead of doing watch on modifiedIndex + 1 we will do watch on X-Etcd-Index,
which is probably still available...
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
When Patroni was "joining" already running postgres it was not calling
callbacks, what in some cases causing issues (callback could be used to
change routing/load-balancer or assign/remove floating (service) ip.
In addition to that we should `start` postgres instead of `restart`-ing
it when doing recovery, because in this case 'on_start' callback should
be called, instead of 'on_restart'
In the original code we were parsing/deparsing url-style connection
strings back and forth. That was not really resource greedy but rather
annoying. Also it was not really obvious how to switch all local
connections to unix-sockets (preferably).
This commit isolates different use-cases of working with connection
strings and minimizes amount of code parsing and deparsing them. Also it
introduces one new helper method in the `Member` object - `conn_kwargs`.
This method can accept as a parameter dict object with credentials
(username and password). As a result it returns dict object which could
be used by `psycopg2.connect` or for building connection urls for
pg_rewind, pg_basebackup or some other replica creation methods.
Params for local connection are builded in the `_local_connect_kwargs`
method and could be changed to unix-socket later easily.
There is no point to try to update topology until original request is
not performed. Also for us it is more important to execute original
request rather then keep topology of etcd cluster in sync.
In addition to that implement the same retry-timeout logic in the
`machines` property which already is used in `api_execute` method.
* Make different kazoo timeouts dependant on loop_wait
ping timeout ~ 1/2 * loop_wait
connect_timeout ~ 1/2 * loop_wait
Originally these values were calculated from negotiated session timeout
and didn't worked very well, because it was taking significant time to
figure out that connection is dead and reconnect (up to session timeout)
and not giving us time to retry.
* Address the code review
