Zhijie Shen commented on YARN-611:

[~xgong], the new patch looks good to me overall. I've just minor comments 
about the patch details.

1. failure account -> failure count?
+ *     when slidingWindowSize is set to > 0, the failure number will no take
+ *     failures which happen out of the window into failure account.
+ *     If failure account reaches to maxAppAttempts,

2. Make get/setSlidingWindowSize description more consistent?

3. EndTime -> FinishTime? The latter term seems to be more commonly used in 

4. end_time violates the code convention.
+      long end_time = attempts.get(attemptIds.get(0)).getEndTime();

5. I think sort is not necessary. We can simply iterator over each attempt and 
check whether it should be take into account. The best sort is O(nlogn), though 
it doesn't make much difference, because there won't be too many attempts. 
Anyway, I think the additional sorting work seems not to be required.
+      Collections.sort(attemptIds, Collections.reverseOrder());

6. Why not using System.currentTimeMillis()?
+    setEndTime(Time.now());

7. In the test case, would you please add one more scenario: 2 failures within 
6s will not restart the 3rd attempt.

> Add an AM retry count reset window to YARN RM
> ---------------------------------------------
>                 Key: YARN-611
>                 URL: https://issues.apache.org/jira/browse/YARN-611
>             Project: Hadoop YARN
>          Issue Type: Sub-task
>          Components: resourcemanager
>    Affects Versions: 2.0.3-alpha
>            Reporter: Chris Riccomini
>            Assignee: Xuan Gong
>         Attachments: YARN-611.1.patch, YARN-611.2.patch, YARN-611.3.patch, 
> YARN-611.4.patch, YARN-611.4.rebase.patch, YARN-611.5.patch, YARN-611.6.patch
> YARN currently has the following config:
> yarn.resourcemanager.am.max-retries
> This config defaults to 2, and defines how many times to retry a "failed" AM 
> before failing the whole YARN job. YARN counts an AM as failed if the node 
> that it was running on dies (the NM will timeout, which counts as a failure 
> for the AM), or if the AM dies.
> This configuration is insufficient for long running (or infinitely running) 
> YARN jobs, since the machine (or NM) that the AM is running on will 
> eventually need to be restarted (or the machine/NM will fail). In such an 
> event, the AM has not done anything wrong, but this is counted as a "failure" 
> by the RM. Since the retry count for the AM is never reset, eventually, at 
> some point, the number of machine/NM failures will result in the AM failure 
> count going above the configured value for 
> yarn.resourcemanager.am.max-retries. Once this happens, the RM will mark the 
> job as failed, and shut it down. This behavior is not ideal.
> I propose that we add a second configuration:
> yarn.resourcemanager.am.retry-count-window-ms
> This configuration would define a window of time that would define when an AM 
> is "well behaved", and it's safe to reset its failure count back to zero. 
> Every time an AM fails the RmAppImpl would check the last time that the AM 
> failed. If the last failure was less than retry-count-window-ms ago, and the 
> new failure count is > max-retries, then the job should fail. If the AM has 
> never failed, the retry count is < max-retries, or if the last failure was 
> OUTSIDE the retry-count-window-ms, then the job should be restarted. 
> Additionally, if the last failure was outside the retry-count-window-ms, then 
> the failure count should be set back to 0.
> This would give developers a way to have well-behaved AMs run forever, while 
> still failing mis-behaving AMs after a short period of time.
> I think the work to be done here is to change the RmAppImpl to actually look 
> at app.attempts, and see if there have been more than max-retries failures in 
> the last retry-count-window-ms milliseconds. If there have, then the job 
> should fail, if not, then the job should go forward. Additionally, we might 
> also need to add an endTime in either RMAppAttemptImpl or 
> RMAppFailedAttemptEvent, so that the RmAppImpl can check the time of the 
> failure.
> Thoughts?

This message was sent by Atlassian JIRA

Reply via email to