GitHub user tillrohrmann opened a pull request:
https://github.com/apache/flink/pull/2257
[FLINK-4152] Allow re-registration of TMs at resource manager
The `YarnFlinkResourceManager` does not allow the `JobManager` to
re-register task managers have had been registered at the resource manager
before. The consequence of the refusal is that the job manager rejects the
registrations of these task managers.
Such a scenario can happen if a `JobManager` loses leadership in an HA
setting after it registered
some TMs. The old behaviour was that the resource manager clears the list
of registered workers and only accepts new registrations of task manager which
have been started in a fresh container. However, in case that the previously
registered TMs didn't die, they will try to reconnect to the new leader. The
new leader will then ask the resource manager whether the TMs represent valid
resources. Since the resource manager forgot about the already started
containers, it rejects the TMs.
This PR changes the behaviour of the resource manager such that it can no
longer reject TMs. Instead of being asked it will simply be informed about the
registered TMs by the JM. If the TM happens to be running in a container which
was started by the RM, then it will monitor this container. In case that this
container dies, the RM will notify the JM about the death of the TM.
In that sense, the RM has no longer the authority to interfere with the
JM-TM interactions and instead it is simply used as an additional monitoring
service to detect dead TMs as a result of a failed container.
Furthermore, the PR adds a de-duplication method to filter out concurrent
registration runs on the task manager. Before, it happened that a
`RefusedRegistration` triggers a new registration run without cancelling the
old registration run. This could lead to a massive amount of registration
messages if the TaskManager's registration was refused multiple times.
The mechanism to de-duplicate `TriggerTaskManagerRegistration` works by
assigning a registration run id which is changed whenever a new registration
run is started. `TriggerTaskManagerRegistration` messages which have an
outdated registration run id are then filtered out.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/tillrohrmann/flink
FLINK-4152_YarnResourceManager
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/2257.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #2257
----
commit 2a29fa4df98fd63a7f27e1607152cd6e54d25ad1
Author: Till Rohrmann <[email protected]>
Date: 2016-07-15T08:51:59Z
Add YarnFlinkResourceManager test to reaccept task manager registrations
from a re-elected job manager
commit 6462d4750d79512fc93bbc60ca754c99142d1794
Author: Till Rohrmann <[email protected]>
Date: 2016-07-15T09:50:35Z
Remove unnecessary sync logic between JobManager and ResourceManager
commit 55ce0c01783d9c4927a9f4677309c805e2b624e7
Author: Till Rohrmann <[email protected]>
Date: 2016-07-15T10:12:12Z
Avoid duplicate reigstration attempts in case of a refused registration
commit aeb6ae5435dd88c640dc314b9ec31357815d080c
Author: Till Rohrmann <[email protected]>
Date: 2016-07-15T13:04:54Z
Add test case to check that not an excessive amount of RegisterTaskManager
messages are sent
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