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Posted to issues@flink.apache.org by tillrohrmann <gi...@git.apache.org> on 2018/06/12 14:20:32 UTC
[GitHub] flink pull request #6154: [FLINK-9573] Extend LeaderElectionService#hasLeade...
GitHub user tillrohrmann opened a pull request:
https://github.com/apache/flink/pull/6154
[FLINK-9573] Extend LeaderElectionService#hasLeadership to take leader session id
## What is the purpose of the change
The new `LeaderElectionService#hasLeadership` also takes the leader session id and verifies whether
this is the correct leader session id associated with the leadership.
## Brief change log
- Extend `LeaderElectionService#hasLeadership` to take a leader session id and check whether it identifies the current leader session
- Adapt the calls to `LeaderElectionService#hasLeadership` to take the current leader session id
## Verifying this change
- Added `LeaderElectionTest`.
## Does this pull request potentially affect one of the following parts:
- Dependencies (does it add or upgrade a dependency): (no)
- The public API, i.e., is any changed class annotated with `@Public(Evolving)`: (no)
- The serializers: (no)
- The runtime per-record code paths (performance sensitive): (no)
- Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (yes)
- The S3 file system connector: (no)
## Documentation
- Does this pull request introduce a new feature? (no)
- If yes, how is the feature documented? (not applicable)
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/tillrohrmann/flink extendLeaderElectionService
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/6154.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 #6154
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commit 54831c6a07dfcd5691fd732148a7c559514362ec
Author: Till Rohrmann <tr...@...>
Date: 2018-06-12T13:22:50Z
[hotfix] Remove Scala dependency from ZooKeeperLeaderElectionTest
commit e50034088f4d85fe457e7015f162a6f86b1de9e7
Author: Till Rohrmann <tr...@...>
Date: 2018-06-12T12:24:59Z
[FLINK-9573] Extend LeaderElectionService#hasLeadership to take leader session id
The new LeaderElectionService#hasLeadership also takes the leader session id and verifies whether
this is the correct leader session id associated with the leadership.
commit 104b46bd7848cd431afc564f6d3bb364a5257cf9
Author: Till Rohrmann <tr...@...>
Date: 2018-06-12T12:40:13Z
[hotfix] Fix checkstyle violations in SingleLeaderElectionService
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[GitHub] flink pull request #6154: [FLINK-9573] Extend LeaderElectionService#hasLeade...
Posted by asfgit <gi...@git.apache.org>.
Github user asfgit closed the pull request at:
https://github.com/apache/flink/pull/6154
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[GitHub] flink pull request #6154: [FLINK-9573] Extend LeaderElectionService#hasLeade...
Posted by tillrohrmann <gi...@git.apache.org>.
Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/6154#discussion_r195359921
--- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedLeaderService.java ---
@@ -356,8 +357,8 @@ public void confirmLeaderSessionID(UUID leaderSessionID) {
}
@Override
- public boolean hasLeadership() {
- return isLeader;
+ public boolean hasLeadership(@Nonnull UUID leaderSessionId) {
+ return isLeader && leaderSessionId.equals(currentLeaderSessionId);
}
--- End diff --
In the case of the `EmbeddedLeaderService`, there is no case in which `leaderSessionId != currentLeaderSessionId` if `isLeader`, because a leader only loses leadership if the service is stopped. But this is an implementation detail which might change in the future and thus, should be guarded.
I think we don't need a lock but have to make `currentLeaderSessionId` `volatile` such that we see modifications.
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[GitHub] flink pull request #6154: [FLINK-9573] Extend LeaderElectionService#hasLeade...
Posted by zhangminglei <gi...@git.apache.org>.
Github user zhangminglei commented on a diff in the pull request:
https://github.com/apache/flink/pull/6154#discussion_r194938580
--- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedLeaderService.java ---
@@ -356,8 +357,8 @@ public void confirmLeaderSessionID(UUID leaderSessionID) {
}
@Override
- public boolean hasLeadership() {
- return isLeader;
+ public boolean hasLeadership(@Nonnull UUID leaderSessionId) {
+ return isLeader && leaderSessionId.equals(currentLeaderSessionId);
}
--- End diff --
I would ask, in what situation, the ```leaderSessionId``` does not equal to ```currentLeaderSessionId``` . When another task update the value ?
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[GitHub] flink pull request #6154: [FLINK-9573] Extend LeaderElectionService#hasLeade...
Posted by zhangminglei <gi...@git.apache.org>.
Github user zhangminglei commented on a diff in the pull request:
https://github.com/apache/flink/pull/6154#discussion_r195613671
--- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/highavailability/nonha/embedded/EmbeddedLeaderService.java ---
@@ -356,8 +357,8 @@ public void confirmLeaderSessionID(UUID leaderSessionID) {
}
@Override
- public boolean hasLeadership() {
- return isLeader;
+ public boolean hasLeadership(@Nonnull UUID leaderSessionId) {
+ return isLeader && leaderSessionId.equals(currentLeaderSessionId);
}
--- End diff --
Thanks @tillrohrmann Makes sense better to me now. Yea, I did not see there has a volatile in there before. Thanks again.
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