Re: Job end notification does not always work (Hadoop 2.x)
Thanks everyone. I have opened a JIRA and added a link to this discussion https://issues.apache.org/jira/browse/MAPREDUCE-5353 On Mon, Jun 24, 2013 at 8:42 PM, Devaraj k devara...@huawei.com wrote: It is not mandatory to have running HS in the cluster. Still the user can submit the job without HS in the cluster, and user may expect the Job/App End Notification. ** ** Thanks Devaraj k ** ** *From:* Alejandro Abdelnur [mailto:t...@cloudera.com] *Sent:* 24 June 2013 21:42 *To:* user@hadoop.apache.org *Cc:* user@hadoop.apache.org *Subject:* Re: Job end notification does not always work (Hadoop 2.x) ** ** if we ought to do this in a yarn service it should be the RM or the HS. the RM is, IMO, the natural fit. the HS, would be a good choice if we are concerned about the extra work this would cause in the RM. the problem with the current HS is that it is MR specific, we should generalize it for diff AM types. ** ** thx Alejandro (phone typing) On Jun 23, 2013, at 23:28, Devaraj k devara...@huawei.com wrote: Even if we handle all the failure cases in AM for Job End Notification, we may miss cases like abrupt kill of AM when it is in last retry. If we choose NM to give the notification, again RM needs to identify which NM should give the end-notification as we don't have any direct protocol between AM and NM. I feel it would be better to move End-Notification responsibility to RM as Yarn Service because it ensures 100% notification and also useful for other types of applications as well. Thanks Devaraj K *From:* Ravi Prakash [mailto:ravi...@ymail.com ravi...@ymail.com] *Sent:* 23 June 2013 19:01 *To:* user@hadoop.apache.org *Subject:* Re: Job end notification does not always work (Hadoop 2.x) Hi Alejandro, Thanks for your reply! I was thinking more along the lines Prashant suggested i.e. a failure during init() should still trigger an attempt to notify (by the AM). But now that you mention it, maybe we would be better of including this as a YARN feature after all (specially with all the new AMs being written). We could let the NM of the AM handle the notification burden, so that the RM doesn't get unduly taxed. Thoughts? Thanks Ravi -- *From:* Alejandro Abdelnur t...@cloudera.com *To:* common-u...@hadoop.apache.org user@hadoop.apache.org *Sent:* Saturday, June 22, 2013 7:37 PM *Subject:* Re: Job end notification does not always work (Hadoop 2.x) If the AM fails before doing the job end notification, at any stage of the execution for whatever reason, the job end notification will never be deliver. There is not way to fix this unless the notification is done by a Yarn service. The 2 'candidate' services for doing this would be the RM and the HS. The job notification URL is in the job conf. The RM never sees the job conf, that rules out the RM out unless we add, at AM registration time the possibility to specify a callback URL. The HS has access to the job conf, but the HS is currently a 'passive' service. thx On Sat, Jun 22, 2013 at 3:48 PM, Arun C Murthy a...@hortonworks.com wrote: Prashanth, Please file a jira. One thing to be aware of - AMs get restarted a certain number of times for fault-tolerance - which means we can't just assume that failure of a single AM is equivalent to failure of the job. Only the ResourceManager is in the appropriate position to judge failure of AM v/s failure-of-job. hth, Arun On Jun 22, 2013, at 2:44 PM, Prashant Kommireddi prash1...@gmail.com wrote: Thanks Ravi. Well, in this case its a no-effort :) A failure of AM init should be considered as failure of the job? I looked at the code and best-effort makes sense with respect to retry logic etc. You make a good point that there would be no notification in case AM OOMs, but I do feel AM init failure should send a notification by other means. On Sat, Jun 22, 2013 at 2:38 PM, Ravi Prakash ravi...@ymail.com wrote:** ** Hi Prashant, I would tend to agree with you. Although job-end notification is only a best-effort mechanism (i.e. we cannot always guarantee notification for example when the AM OOMs), I agree with you that we can do more. If you feel strongly about this, please create a JIRA and possibly upload a patch. Thanks Ravi -- *From:* Prashant Kommireddi prash1...@gmail.com *To:* user@hadoop.apache.org user@hadoop.apache.org *Sent:* Thursday, June 20, 2013 9:45 PM *Subject:* Job end notification does not always work (Hadoop 2.x) Hello, I came across an issue that occurs with the job notification callbacks in MR2. It works fine if the Application master has
Re: Job end notification does not always work (Hadoop 2.x)
Devaraj, If you don't run the HS, once your jobs finished you cannot retrieve status/counters from it, from Java AP or Web UI. So I'd for any practical usage, you need it. thx On Mon, Jun 24, 2013 at 8:42 PM, Devaraj k devara...@huawei.com wrote: It is not mandatory to have running HS in the cluster. Still the user can submit the job without HS in the cluster, and user may expect the Job/App End Notification. ** ** Thanks Devaraj k ** ** *From:* Alejandro Abdelnur [mailto:t...@cloudera.com] *Sent:* 24 June 2013 21:42 *To:* user@hadoop.apache.org *Cc:* user@hadoop.apache.org *Subject:* Re: Job end notification does not always work (Hadoop 2.x) ** ** if we ought to do this in a yarn service it should be the RM or the HS. the RM is, IMO, the natural fit. the HS, would be a good choice if we are concerned about the extra work this would cause in the RM. the problem with the current HS is that it is MR specific, we should generalize it for diff AM types. ** ** thx Alejandro (phone typing) On Jun 23, 2013, at 23:28, Devaraj k devara...@huawei.com wrote: Even if we handle all the failure cases in AM for Job End Notification, we may miss cases like abrupt kill of AM when it is in last retry. If we choose NM to give the notification, again RM needs to identify which NM should give the end-notification as we don't have any direct protocol between AM and NM. I feel it would be better to move End-Notification responsibility to RM as Yarn Service because it ensures 100% notification and also useful for other types of applications as well. Thanks Devaraj K *From:* Ravi Prakash [mailto:ravi...@ymail.com ravi...@ymail.com] *Sent:* 23 June 2013 19:01 *To:* user@hadoop.apache.org *Subject:* Re: Job end notification does not always work (Hadoop 2.x) Hi Alejandro, Thanks for your reply! I was thinking more along the lines Prashant suggested i.e. a failure during init() should still trigger an attempt to notify (by the AM). But now that you mention it, maybe we would be better of including this as a YARN feature after all (specially with all the new AMs being written). We could let the NM of the AM handle the notification burden, so that the RM doesn't get unduly taxed. Thoughts? Thanks Ravi -- *From:* Alejandro Abdelnur t...@cloudera.com *To:* common-u...@hadoop.apache.org user@hadoop.apache.org *Sent:* Saturday, June 22, 2013 7:37 PM *Subject:* Re: Job end notification does not always work (Hadoop 2.x) If the AM fails before doing the job end notification, at any stage of the execution for whatever reason, the job end notification will never be deliver. There is not way to fix this unless the notification is done by a Yarn service. The 2 'candidate' services for doing this would be the RM and the HS. The job notification URL is in the job conf. The RM never sees the job conf, that rules out the RM out unless we add, at AM registration time the possibility to specify a callback URL. The HS has access to the job conf, but the HS is currently a 'passive' service. thx On Sat, Jun 22, 2013 at 3:48 PM, Arun C Murthy a...@hortonworks.com wrote: Prashanth, Please file a jira. One thing to be aware of - AMs get restarted a certain number of times for fault-tolerance - which means we can't just assume that failure of a single AM is equivalent to failure of the job. Only the ResourceManager is in the appropriate position to judge failure of AM v/s failure-of-job. hth, Arun On Jun 22, 2013, at 2:44 PM, Prashant Kommireddi prash1...@gmail.com wrote: Thanks Ravi. Well, in this case its a no-effort :) A failure of AM init should be considered as failure of the job? I looked at the code and best-effort makes sense with respect to retry logic etc. You make a good point that there would be no notification in case AM OOMs, but I do feel AM init failure should send a notification by other means. On Sat, Jun 22, 2013 at 2:38 PM, Ravi Prakash ravi...@ymail.com wrote:** ** Hi Prashant, I would tend to agree with you. Although job-end notification is only a best-effort mechanism (i.e. we cannot always guarantee notification for example when the AM OOMs), I agree with you that we can do more. If you feel strongly about this, please create a JIRA and possibly upload a patch. Thanks Ravi -- *From:* Prashant Kommireddi prash1...@gmail.com *To:* user@hadoop.apache.org user@hadoop.apache.org *Sent:* Thursday, June 20, 2013 9:45 PM *Subject:* Job end notification does not always work (Hadoop 2.x) Hello, I came across an issue that occurs with the job notification callbacks
RE: Job end notification does not always work (Hadoop 2.x)
I agree, for getting status/counters we need HS. I mean Job can finish without HS also. Thanks Devaraj k From: Alejandro Abdelnur [mailto:t...@cloudera.com] Sent: 25 June 2013 18:05 To: common-u...@hadoop.apache.org Subject: Re: Job end notification does not always work (Hadoop 2.x) Devaraj, If you don't run the HS, once your jobs finished you cannot retrieve status/counters from it, from Java AP or Web UI. So I'd for any practical usage, you need it. thx On Mon, Jun 24, 2013 at 8:42 PM, Devaraj k devara...@huawei.commailto:devara...@huawei.com wrote: It is not mandatory to have running HS in the cluster. Still the user can submit the job without HS in the cluster, and user may expect the Job/App End Notification. Thanks Devaraj k From: Alejandro Abdelnur [mailto:t...@cloudera.commailto:t...@cloudera.com] Sent: 24 June 2013 21:42 To: user@hadoop.apache.orgmailto:user@hadoop.apache.org Cc: user@hadoop.apache.orgmailto:user@hadoop.apache.org Subject: Re: Job end notification does not always work (Hadoop 2.x) if we ought to do this in a yarn service it should be the RM or the HS. the RM is, IMO, the natural fit. the HS, would be a good choice if we are concerned about the extra work this would cause in the RM. the problem with the current HS is that it is MR specific, we should generalize it for diff AM types. thx Alejandro (phone typing) On Jun 23, 2013, at 23:28, Devaraj k devara...@huawei.commailto:devara...@huawei.com wrote: Even if we handle all the failure cases in AM for Job End Notification, we may miss cases like abrupt kill of AM when it is in last retry. If we choose NM to give the notification, again RM needs to identify which NM should give the end-notification as we don't have any direct protocol between AM and NM. I feel it would be better to move End-Notification responsibility to RM as Yarn Service because it ensures 100% notification and also useful for other types of applications as well. Thanks Devaraj K From: Ravi Prakash [mailto:ravi...@ymail.com] Sent: 23 June 2013 19:01 To: user@hadoop.apache.orgmailto:user@hadoop.apache.org Subject: Re: Job end notification does not always work (Hadoop 2.x) Hi Alejandro, Thanks for your reply! I was thinking more along the lines Prashant suggested i.e. a failure during init() should still trigger an attempt to notify (by the AM). But now that you mention it, maybe we would be better of including this as a YARN feature after all (specially with all the new AMs being written). We could let the NM of the AM handle the notification burden, so that the RM doesn't get unduly taxed. Thoughts? Thanks Ravi From: Alejandro Abdelnur t...@cloudera.commailto:t...@cloudera.com To: common-u...@hadoop.apache.orgmailto:common-u...@hadoop.apache.org user@hadoop.apache.orgmailto:user@hadoop.apache.org Sent: Saturday, June 22, 2013 7:37 PM Subject: Re: Job end notification does not always work (Hadoop 2.x) If the AM fails before doing the job end notification, at any stage of the execution for whatever reason, the job end notification will never be deliver. There is not way to fix this unless the notification is done by a Yarn service. The 2 'candidate' services for doing this would be the RM and the HS. The job notification URL is in the job conf. The RM never sees the job conf, that rules out the RM out unless we add, at AM registration time the possibility to specify a callback URL. The HS has access to the job conf, but the HS is currently a 'passive' service. thx On Sat, Jun 22, 2013 at 3:48 PM, Arun C Murthy a...@hortonworks.commailto:a...@hortonworks.com wrote: Prashanth, Please file a jira. One thing to be aware of - AMs get restarted a certain number of times for fault-tolerance - which means we can't just assume that failure of a single AM is equivalent to failure of the job. Only the ResourceManager is in the appropriate position to judge failure of AM v/s failure-of-job. hth, Arun On Jun 22, 2013, at 2:44 PM, Prashant Kommireddi prash1...@gmail.commailto:prash1...@gmail.com wrote: Thanks Ravi. Well, in this case its a no-effort :) A failure of AM init should be considered as failure of the job? I looked at the code and best-effort makes sense with respect to retry logic etc. You make a good point that there would be no notification in case AM OOMs, but I do feel AM init failure should send a notification by other means. On Sat, Jun 22, 2013 at 2:38 PM, Ravi Prakash ravi...@ymail.commailto:ravi...@ymail.com wrote: Hi Prashant, I would tend to agree with you. Although job-end notification is only a best-effort mechanism (i.e. we cannot always guarantee notification for example when the AM OOMs), I agree with you that we can do more. If you feel strongly about this, please create a JIRA and possibly upload a patch. Thanks Ravi From: Prashant Kommireddi prash1...@gmail.commailto:prash1...@gmail.com To: user
Re: Job end notification does not always work (Hadoop 2.x)
Devaraj, if a job can finish but you cannot determine it status after it ended, then the system is not usable. Thus, HS is a required component. thx On Tue, Jun 25, 2013 at 6:11 AM, Devaraj k devara...@huawei.com wrote: I agree, for getting status/counters we need HS. I mean Job can finish without HS also. ** ** Thanks Devaraj k ** ** *From:* Alejandro Abdelnur [mailto:t...@cloudera.com] *Sent:* 25 June 2013 18:05 *To:* common-u...@hadoop.apache.org *Subject:* Re: Job end notification does not always work (Hadoop 2.x) ** ** Devaraj, ** ** If you don't run the HS, once your jobs finished you cannot retrieve status/counters from it, from Java AP or Web UI. So I'd for any practical usage, you need it. ** ** thx ** ** On Mon, Jun 24, 2013 at 8:42 PM, Devaraj k devara...@huawei.com wrote:** ** It is not mandatory to have running HS in the cluster. Still the user can submit the job without HS in the cluster, and user may expect the Job/App End Notification. Thanks Devaraj k *From:* Alejandro Abdelnur [mailto:t...@cloudera.com] *Sent:* 24 June 2013 21:42 *To:* user@hadoop.apache.org *Cc:* user@hadoop.apache.org *Subject:* Re: Job end notification does not always work (Hadoop 2.x) if we ought to do this in a yarn service it should be the RM or the HS. the RM is, IMO, the natural fit. the HS, would be a good choice if we are concerned about the extra work this would cause in the RM. the problem with the current HS is that it is MR specific, we should generalize it for diff AM types. thx Alejandro (phone typing) On Jun 23, 2013, at 23:28, Devaraj k devara...@huawei.com wrote: Even if we handle all the failure cases in AM for Job End Notification, we may miss cases like abrupt kill of AM when it is in last retry. If we choose NM to give the notification, again RM needs to identify which NM should give the end-notification as we don't have any direct protocol between AM and NM. I feel it would be better to move End-Notification responsibility to RM as Yarn Service because it ensures 100% notification and also useful for other types of applications as well. Thanks Devaraj K *From:* Ravi Prakash [mailto:ravi...@ymail.com ravi...@ymail.com] *Sent:* 23 June 2013 19:01 *To:* user@hadoop.apache.org *Subject:* Re: Job end notification does not always work (Hadoop 2.x) Hi Alejandro, Thanks for your reply! I was thinking more along the lines Prashant suggested i.e. a failure during init() should still trigger an attempt to notify (by the AM). But now that you mention it, maybe we would be better of including this as a YARN feature after all (specially with all the new AMs being written). We could let the NM of the AM handle the notification burden, so that the RM doesn't get unduly taxed. Thoughts? Thanks Ravi -- *From:* Alejandro Abdelnur t...@cloudera.com *To:* common-u...@hadoop.apache.org user@hadoop.apache.org *Sent:* Saturday, June 22, 2013 7:37 PM *Subject:* Re: Job end notification does not always work (Hadoop 2.x) If the AM fails before doing the job end notification, at any stage of the execution for whatever reason, the job end notification will never be deliver. There is not way to fix this unless the notification is done by a Yarn service. The 2 'candidate' services for doing this would be the RM and the HS. The job notification URL is in the job conf. The RM never sees the job conf, that rules out the RM out unless we add, at AM registration time the possibility to specify a callback URL. The HS has access to the job conf, but the HS is currently a 'passive' service. thx On Sat, Jun 22, 2013 at 3:48 PM, Arun C Murthy a...@hortonworks.com wrote: Prashanth, Please file a jira. One thing to be aware of - AMs get restarted a certain number of times for fault-tolerance - which means we can't just assume that failure of a single AM is equivalent to failure of the job. Only the ResourceManager is in the appropriate position to judge failure of AM v/s failure-of-job. hth, Arun On Jun 22, 2013, at 2:44 PM, Prashant Kommireddi prash1...@gmail.com wrote: Thanks Ravi. Well, in this case its a no-effort :) A failure of AM init should be considered as failure of the job? I looked at the code and best-effort makes sense with respect to retry logic etc. You make a good point that there would be no notification in case AM OOMs, but I do feel AM init failure should send a notification by other means. On Sat, Jun 22, 2013 at 2:38 PM, Ravi Prakash ravi...@ymail.com wrote:** ** Hi Prashant, I would tend to agree with you. Although job-end
RE: Job end notification does not always work (Hadoop 2.x)
Even if we handle all the failure cases in AM for Job End Notification, we may
miss cases like abrupt kill of AM when it is in last retry. If we choose NM to
give the notification, again RM needs to identify which NM should give the
end-notification as we don't have any direct protocol between AM and NM.
I feel it would be better to move End-Notification responsibility to RM as Yarn
Service because it ensures 100% notification and also useful for other types of
applications as well.
Thanks
Devaraj K
From: Ravi Prakash [mailto:ravi...@ymail.com]
Sent: 23 June 2013 19:01
To: user@hadoop.apache.org
Subject: Re: Job end notification does not always work (Hadoop 2.x)
Hi Alejandro,
Thanks for your reply! I was thinking more along the lines Prashant suggested
i.e. a failure during init() should still trigger an attempt to notify (by the
AM). But now that you mention it, maybe we would be better of including this as
a YARN feature after all (specially with all the new AMs being written). We
could let the NM of the AM handle the notification burden, so that the RM
doesn't get unduly taxed. Thoughts?
Thanks
Ravi
From: Alejandro Abdelnur t...@cloudera.commailto:t...@cloudera.com
To: common-u...@hadoop.apache.orgmailto:common-u...@hadoop.apache.org
user@hadoop.apache.orgmailto:user@hadoop.apache.org
Sent: Saturday, June 22, 2013 7:37 PM
Subject: Re: Job end notification does not always work (Hadoop 2.x)
If the AM fails before doing the job end notification, at any stage of the
execution for whatever reason, the job end notification will never be deliver.
There is not way to fix this unless the notification is done by a Yarn service.
The 2 'candidate' services for doing this would be the RM and the HS. The job
notification URL is in the job conf. The RM never sees the job conf, that rules
out the RM out unless we add, at AM registration time the possibility to
specify a callback URL. The HS has access to the job conf, but the HS is
currently a 'passive' service.
thx
On Sat, Jun 22, 2013 at 3:48 PM, Arun C Murthy
a...@hortonworks.commailto:a...@hortonworks.com wrote:
Prashanth,
Please file a jira.
One thing to be aware of - AMs get restarted a certain number of times for
fault-tolerance - which means we can't just assume that failure of a single AM
is equivalent to failure of the job.
Only the ResourceManager is in the appropriate position to judge failure of AM
v/s failure-of-job.
hth,
Arun
On Jun 22, 2013, at 2:44 PM, Prashant Kommireddi
prash1...@gmail.commailto:prash1...@gmail.com wrote:
Thanks Ravi.
Well, in this case its a no-effort :) A failure of AM init should be considered
as failure of the job? I looked at the code and best-effort makes sense with
respect to retry logic etc. You make a good point that there would be no
notification in case AM OOMs, but I do feel AM init failure should send a
notification by other means.
On Sat, Jun 22, 2013 at 2:38 PM, Ravi Prakash
ravi...@ymail.commailto:ravi...@ymail.com wrote:
Hi Prashant,
I would tend to agree with you. Although job-end notification is only a
best-effort mechanism (i.e. we cannot always guarantee notification for
example when the AM OOMs), I agree with you that we can do more. If you feel
strongly about this, please create a JIRA and possibly upload a patch.
Thanks
Ravi
From: Prashant Kommireddi prash1...@gmail.commailto:prash1...@gmail.com
To: user@hadoop.apache.orgmailto:user@hadoop.apache.org
user@hadoop.apache.orgmailto:user@hadoop.apache.org
Sent: Thursday, June 20, 2013 9:45 PM
Subject: Job end notification does not always work (Hadoop 2.x)
Hello,
I came across an issue that occurs with the job notification callbacks in MR2.
It works fine if the Application master has started, but does not send a
callback if the initializing of AM fails.
Here is the code from MRAppMaster.java
.
...
// set job classloader if configured
MRApps.setJobClassLoader(conf);
initAndStartAppMaster(appMaster, conf, jobUserName);
} catch (Throwable t) {
LOG.fatal(Error starting MRAppMaster, t);
System.exit(1);
}
}
protected static void initAndStartAppMaster(final MRAppMaster appMaster,
final YarnConfiguration conf, String jobUserName) throws IOException,
InterruptedException {
UserGroupInformation.setConfiguration(conf);
UserGroupInformation appMasterUgi = UserGroupInformation
.createRemoteUser(jobUserName);
appMasterUgi.doAs(new PrivilegedExceptionActionObject() {
@Override
public Object run() throws Exception {
appMaster.init(conf);
appMaster.start();
if(appMaster.errorHappenedShutDown) {
throw new IOException(Was asked to shut down.);
}
return null;
}
});
}
appMaster.init(conf) does not dispatch JobFinishEventHandler which is
responsible for sending a HTTP callback
Re: Job end notification does not always work (Hadoop 2.x)
if we ought to do this in a yarn service it
should be the RM or the HS. the RM is, IMO, the natural fit. the HS, would be a
good choice if we are concerned about the extra work this would cause in the
RM. the problem with the current HS is that it is MR specific, we should
generalize it for diff AM types.
thx
Alejandro
(phone typing)
On Jun 23, 2013, at 23:28, Devaraj k devara...@huawei.com wrote:
Even if we handle all the failure cases in AM for Job End Notification, we
may miss cases like abrupt kill of AM when it is in last retry. If we choose
NM to give the notification, again RM needs to identify which NM should give
the end-notification as we don't have any direct protocol between AM and NM.
I feel it would be better to move End-Notification responsibility to RM as
Yarn Service because it ensures 100% notification and also useful for other
types of applications as well.
Thanks
Devaraj K
From: Ravi Prakash [mailto:ravi...@ymail.com]
Sent: 23 June 2013 19:01
To: user@hadoop.apache.org
Subject: Re: Job end notification does not always work (Hadoop 2.x)
Hi Alejandro,
Thanks for your reply! I was thinking more along the lines Prashant suggested
i.e. a failure during init() should still trigger an attempt to notify (by
the AM). But now that you mention it, maybe we would be better of including
this as a YARN feature after all (specially with all the new AMs being
written). We could let the NM of the AM handle the notification burden, so
that the RM doesn't get unduly taxed. Thoughts?
Thanks
Ravi
From: Alejandro Abdelnur t...@cloudera.com
To: common-u...@hadoop.apache.org user@hadoop.apache.org
Sent: Saturday, June 22, 2013 7:37 PM
Subject: Re: Job end notification does not always work (Hadoop 2.x)
If the AM fails before doing the job end notification, at any stage of the
execution for whatever reason, the job end notification will never be
deliver. There is not way to fix this unless the notification is done by a
Yarn service. The 2 'candidate' services for doing this would be the RM and
the HS. The job notification URL is in the job conf. The RM never sees the
job conf, that rules out the RM out unless we add, at AM registration time
the possibility to specify a callback URL. The HS has access to the job conf,
but the HS is currently a 'passive' service.
thx
On Sat, Jun 22, 2013 at 3:48 PM, Arun C Murthy a...@hortonworks.com wrote:
Prashanth,
Please file a jira.
One thing to be aware of - AMs get restarted a certain number of times for
fault-tolerance - which means we can't just assume that failure of a single
AM is equivalent to failure of the job.
Only the ResourceManager is in the appropriate position to judge failure of
AM v/s failure-of-job.
hth,
Arun
On Jun 22, 2013, at 2:44 PM, Prashant Kommireddi prash1...@gmail.com wrote:
Thanks Ravi.
Well, in this case its a no-effort :) A failure of AM init should be
considered as failure of the job? I looked at the code and best-effort makes
sense with respect to retry logic etc. You make a good point that there would
be no notification in case AM OOMs, but I do feel AM init failure should send
a notification by other means.
On Sat, Jun 22, 2013 at 2:38 PM, Ravi Prakash ravi...@ymail.com wrote:
Hi Prashant,
I would tend to agree with you. Although job-end notification is only a
best-effort mechanism (i.e. we cannot always guarantee notification for
example when the AM OOMs), I agree with you that we can do more. If you feel
strongly about this, please create a JIRA and possibly upload a patch.
Thanks
Ravi
From: Prashant Kommireddi prash1...@gmail.com
To: user@hadoop.apache.org user@hadoop.apache.org
Sent: Thursday, June 20, 2013 9:45 PM
Subject: Job end notification does not always work (Hadoop 2.x)
Hello,
I came across an issue that occurs with the job notification callbacks in
MR2. It works fine if the Application master has started, but does not send a
callback if the initializing of AM fails.
Here is the code from MRAppMaster.java
.
...
// set job classloader if configured
MRApps.setJobClassLoader(conf);
initAndStartAppMaster(appMaster, conf, jobUserName);
} catch (Throwable t) {
LOG.fatal(Error starting MRAppMaster, t);
System.exit(1);
}
}
protected static void initAndStartAppMaster(final MRAppMaster appMaster,
final YarnConfiguration conf, String jobUserName) throws IOException,
InterruptedException {
UserGroupInformation.setConfiguration(conf);
UserGroupInformation appMasterUgi = UserGroupInformation
.createRemoteUser(jobUserName);
appMasterUgi.doAs(new PrivilegedExceptionActionObject() {
@Override
public Object run() throws Exception {
appMaster.init(conf);
appMaster.start();
if(appMaster.errorHappenedShutDown
Re: Job end notification does not always work (Hadoop 2.x)
Hi Alejandro,
Thanks for your reply! I was thinking more along the lines Prashant suggested
i.e. a failure during init() should still trigger an attempt to notify (by the
AM). But now that you mention it, maybe we would be better of including this as
a YARN feature after all (specially with all the new AMs being written). We
could let the NM of the AM handle the notification burden, so that the RM
doesn't get unduly taxed. Thoughts?
Thanks
Ravi
From: Alejandro Abdelnur t...@cloudera.com
To: common-u...@hadoop.apache.org user@hadoop.apache.org
Sent: Saturday, June 22, 2013 7:37 PM
Subject: Re: Job end notification does not always work (Hadoop 2.x)
If the AM fails before doing the job end notification, at any stage of the
execution for whatever reason, the job end notification will never be deliver.
There is not way to fix this unless the notification is done by a Yarn service.
The 2 'candidate' services for doing this would be the RM and the HS. The job
notification URL is in the job conf. The RM never sees the job conf, that rules
out the RM out unless we add, at AM registration time the possibility to
specify a callback URL. The HS has access to the job conf, but the HS is
currently a 'passive' service.
thx
On Sat, Jun 22, 2013 at 3:48 PM, Arun C Murthy a...@hortonworks.com wrote:
Prashanth,
Please file a jira.
One thing to be aware of - AMs get restarted a certain number of times for
fault-tolerance - which means we can't just assume that failure of a single AM
is equivalent to failure of the job.
Only the ResourceManager is in the appropriate position to judge failure of
AM v/s failure-of-job.
hth,
Arun
On Jun 22, 2013, at 2:44 PM, Prashant Kommireddi prash1...@gmail.com wrote:
Thanks Ravi.
Well, in this case its a no-effort :) A failure of AM init should be
considered as failure of the job? I looked at the code and best-effort makes
sense with respect to retry logic etc. You make a good point that there would
be no notification in case AM OOMs, but I do feel AM init failure should send
a notification by other means.
On Sat, Jun 22, 2013 at 2:38 PM, Ravi Prakash ravi...@ymail.com wrote:
Hi Prashant,
I would tend to agree with you. Although job-end notification is only a
best-effort mechanism (i.e. we cannot always guarantee notification for
example when the AM OOMs), I agree with you that we can do more. If you feel
strongly about this, please create a JIRA and possibly upload a patch.
Thanks
Ravi
From: Prashant Kommireddi prash1...@gmail.com
To: user@hadoop.apache.org user@hadoop.apache.org
Sent: Thursday, June 20, 2013 9:45 PM
Subject: Job end notification does not always work (Hadoop 2.x)
Hello,
I came across an issue that occurs with the job notification callbacks in
MR2. It works fine if the Application master has started, but does not send
a callback if the initializing of AM fails.
Here is the code from MRAppMaster.java
.
...
// set job classloader if configured MRApps.setJobClassLoader(conf);
initAndStartAppMaster(appMaster, conf, jobUserName); } catch (Throwable t) {
LOG.fatal(Error starting MRAppMaster, t); System.exit(1); } }
protected static void initAndStartAppMaster(final MRAppMaster appMaster,
final YarnConfiguration conf, String jobUserName) throws IOException,
InterruptedException {
UserGroupInformation.setConfiguration(conf);
UserGroupInformation appMasterUgi = UserGroupInformation
.createRemoteUser(jobUserName);
appMasterUgi.doAs(new PrivilegedExceptionActionObject() {
@Override
public Object run() throws Exception {
appMaster.init(conf);
appMaster.start();
if(appMaster.errorHappenedShutDown) {
throw new IOException(Was asked to shut down.);
}
return null;
}
});
}
appMaster.init(conf) does not dispatch JobFinishEventHandler which is
responsible for sending a HTTP callback (via shutDownJob()). If there was an
exception at this time, the process would simply terminate (via
System.exit(1) )
appMaster.start() however rightly uses the JobFinishEventHandler and things
work fine.
Shouldn't a failure on init(..) also send a callback suggesting the job
failed?
Thanks,
Prashant
--
Arun C. Murthy
Hortonworks Inc.
http://hortonworks.com/
--
Alejandro
Re: Job end notification does not always work (Hadoop 2.x)
Following-up on this. Please let me know if this is expected/bug and if you
would like me to file a JIRA
On Thu, Jun 20, 2013 at 9:45 PM, Prashant Kommireddi prash1...@gmail.comwrote:
Hello,
I came across an issue that occurs with the job notification callbacks in
MR2. It works fine if the Application master has started, but does not send
a callback if the initializing of AM fails.
Here is the code from MRAppMaster.java
.
...
// set job classloader if configured
MRApps.setJobClassLoader(conf);
initAndStartAppMaster(appMaster, conf, jobUserName);
} catch (Throwable t) {
LOG.fatal(Error starting MRAppMaster, t);
System.exit(1);
}
}
protected static void initAndStartAppMaster(final MRAppMaster appMaster,
final YarnConfiguration conf, String jobUserName) throws IOException,
InterruptedException {
UserGroupInformation.setConfiguration(conf);
UserGroupInformation appMasterUgi = UserGroupInformation
.createRemoteUser(jobUserName);
appMasterUgi.doAs(new PrivilegedExceptionActionObject() {
@Override
public Object run() throws Exception {
appMaster.init(conf);
appMaster.start();
if(appMaster.errorHappenedShutDown) {
throw new IOException(Was asked to shut down.);
}
return null;
}
});
}
appMaster.init(conf) does not dispatch JobFinishEventHandler which is
responsible for sending a HTTP callback (via shutDownJob()). If there was
an exception at this time, the process would simply terminate (via
System.exit(1) )
appMaster.start() however rightly uses the JobFinishEventHandler and
things work fine.
Shouldn't a failure on init(..) also send a callback suggesting the job
failed?
Thanks,
Prashant
Re: Job end notification does not always work (Hadoop 2.x)
Hi Prashant,
I would tend to agree with you. Although job-end notification is only a
best-effort mechanism (i.e. we cannot always guarantee notification for
example when the AM OOMs), I agree with you that we can do more. If you feel
strongly about this, please create a JIRA and possibly upload a patch.
Thanks
Ravi
From: Prashant Kommireddi prash1...@gmail.com
To: user@hadoop.apache.org user@hadoop.apache.org
Sent: Thursday, June 20, 2013 9:45 PM
Subject: Job end notification does not always work (Hadoop 2.x)
Hello,
I came across an issue that occurs with the job notification callbacks in MR2.
It works fine if the Application master has started, but does not send a
callback if the initializing of AM fails.
Here is the code from MRAppMaster.java
.
...
// set job classloader if configured MRApps.setJobClassLoader(conf);
initAndStartAppMaster(appMaster, conf, jobUserName); } catch (Throwable t) {
LOG.fatal(Error starting MRAppMaster, t); System.exit(1); } }
protected static void initAndStartAppMaster(final MRAppMaster appMaster,
final YarnConfiguration conf, String jobUserName) throws IOException,
InterruptedException {
UserGroupInformation.setConfiguration(conf);
UserGroupInformation appMasterUgi = UserGroupInformation
.createRemoteUser(jobUserName);
appMasterUgi.doAs(new PrivilegedExceptionActionObject() {
@Override
public Object run() throws Exception {
appMaster.init(conf);
appMaster.start();
if(appMaster.errorHappenedShutDown) {
throw new IOException(Was asked to shut down.);
}
return null;
}
});
}
appMaster.init(conf) does not dispatch JobFinishEventHandler which is
responsible for sending a HTTP callback (via shutDownJob()). If there was an
exception at this time, the process would simply terminate (via System.exit(1) )
appMaster.start() however rightly uses the JobFinishEventHandler and things
work fine.
Shouldn't a failure on init(..) also send a callback suggesting the job failed?
Thanks,
Prashant
Re: Job end notification does not always work (Hadoop 2.x)
Thanks Ravi.
Well, in this case its a no-effort :) A failure of AM init should be
considered as failure of the job? I looked at the code and best-effort
makes sense with respect to retry logic etc. You make a good point that
there would be no notification in case AM OOMs, but I do feel AM init
failure should send a notification by other means.
On Sat, Jun 22, 2013 at 2:38 PM, Ravi Prakash ravi...@ymail.com wrote:
Hi Prashant,
I would tend to agree with you. Although job-end notification is only a
best-effort mechanism (i.e. we cannot always guarantee notification for
example when the AM OOMs), I agree with you that we can do more. If you
feel strongly about this, please create a JIRA and possibly upload a patch.
Thanks
Ravi
--
*From:* Prashant Kommireddi prash1...@gmail.com
*To:* user@hadoop.apache.org user@hadoop.apache.org
*Sent:* Thursday, June 20, 2013 9:45 PM
*Subject:* Job end notification does not always work (Hadoop 2.x)
Hello,
I came across an issue that occurs with the job notification callbacks in
MR2. It works fine if the Application master has started, but does not send
a callback if the initializing of AM fails.
Here is the code from MRAppMaster.java
.
...
// set job classloader if configured
MRApps.setJobClassLoader(conf);
initAndStartAppMaster(appMaster, conf, jobUserName);
} catch (Throwable t) {
LOG.fatal(Error starting MRAppMaster, t);
System.exit(1);
}
}
protected static void initAndStartAppMaster(final MRAppMaster appMaster,
final YarnConfiguration conf, String jobUserName) throws IOException,
InterruptedException {
UserGroupInformation.setConfiguration(conf);
UserGroupInformation appMasterUgi = UserGroupInformation
.createRemoteUser(jobUserName);
appMasterUgi.doAs(new PrivilegedExceptionActionObject() {
@Override
public Object run() throws Exception {
appMaster.init(conf);
appMaster.start();
if(appMaster.errorHappenedShutDown) {
throw new IOException(Was asked to shut down.);
}
return null;
}
});
}
appMaster.init(conf) does not dispatch JobFinishEventHandler which is
responsible for sending a HTTP callback (via shutDownJob()). If there was
an exception at this time, the process would simply terminate (via
System.exit(1) )
appMaster.start() however rightly uses the JobFinishEventHandler and
things work fine.
Shouldn't a failure on init(..) also send a callback suggesting the job
failed?
Thanks,
Prashant
