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From Caizhi Weng <tsreape...@gmail.com>
Subject Re: Metrics for Task States
Date Mon, 25 Nov 2019 09:41:42 GMT
Hi Kelly,

As far as I know Flink currently does not have such metrics to monitor on
the number of tasks in each states. See
https://ci.apache.org/projects/flink/flink-docs-stable/monitoring/metrics.html
for
the complete metrics list. (It seems that `taskSlotsAvailable` in the
metrics list is the most related metrics).

But Flink has a REST api which can provide states for all the tasks
(http://hostname:port/overview). This REST returns a json string containing
all the metrics you want. Maybe you can write your own tool to monitor on
this api.

If you really want to have metrics that describe the number of tasks in
each states, you can open up a JIRA ticket at
https://issues.apache.org/jira/projects/FLINK/issues/

Thank you

Kelly Smith <kellysm@zillowgroup.com> 于2019年11月25日周一 上午12:59写道:

> With EMR/YARN, the cluster is definitely running in session mode. It
> exists independently of any job and continues running after the job exits.
>
> Whether or not this is a bug in Flink, is it possible to get access to the
> metrics I'm asking about? Those would be useful even if this behavior is
> fixed.
>
> Get Outlook for Android <https://aka.ms/ghei36>
>
> ------------------------------
> *From:* Piper Piper <piperflink@gmail.com>
> *Sent:* Friday, November 22, 2019 9:10:41 PM
> *To:* Kelly Smith <kellysm@zillowgroup.com>
> *Cc:* user@flink.apache.org <user@flink.apache.org>
> *Subject:* Re: Metrics for Task States
>
> I am trying to reason why this problem should occur (i.e. why Flink could
> not reject the job when it required more slots than were available).
>
> Flink in production on EMR (YARN): Does this mean Flink was being run in
> Job mode or Session mode?
>
> Thank you,
>
> Piper
>
> On Thu, Nov 21, 2019 at 4:56 PM Piper Piper <piperflink@gmail.com> wrote:
>
> Thank you, Kelly!
>
> On Thu, Nov 21, 2019 at 4:06 PM Kelly Smith <kellysm@zillowgroup.com>
> wrote:
>
> Hi Piper,
>
>
>
> The repro is pretty simple:
>
>    - Submit a job with parallelism set higher than YARN has resources to
>    support
>
>
>
> What this ends up looking like in the Flink UI is this:
>
>
>
> The Job is in a “RUNNING” state, but all of the tasks are in the
> “SCHEDULED” state. The `jobmanager.numRunningJobs` metric that Flink emits
> by default will increase by 1, but none of the tasks actually get scheduled
> on any TM.
>
>
>
>
>
> What I’m looking for is a way to detect when I am in this state using
> Flink metrics (ideally the count of tasks in each state for better
> observability).
>
>
>
> Does that make sense?
>
>
>
> Thanks,
>
> Kelly
>
>
>
> *From: *Piper Piper <piperflink@gmail.com>
> *Date: *Thursday, November 21, 2019 at 12:59 PM
> *To: *Kelly Smith <kellysm@zillowgroup.com>
> *Cc: *"user@flink.apache.org" <user@flink.apache.org>
> *Subject: *Re: Metrics for Task States
>
>
>
> Hello Kelly,
>
>
>
> I thought that Flink scheduler only starts a job if all requested
> containers/TMs are available and allotted to that job.
>
>
>
> How can I reproduce your issue on Flink with YARN?
>
>
>
> Thank you,
>
>
>
> Piper
>
>
>
>
>
> On Thu, Nov 21, 2019, 1:48 PM Kelly Smith <kellysm@zillowgroup.com> wrote:
>
> I’ve been running Flink in production on EMR (YARN) for some time and have
> found the metrics system to be quite useful, but there is one specific case
> where I’m missing a signal for this scenario:
>
>
>
>    - When a job has been submitted, but YARN does not have enough
>    resources to provide
>
>
>
> Observed:
>
>    - Job is in RUNNING state
>    - All of the tasks for the job are in the (I believe) DEPLOYING state
>
>
>
> Is there a way to access these as metrics for monitoring the number of
> tasks in each state for a given job (image below)? The metric I’m currently
> using is the number of running jobs, but it misses this “unhealthy”
> scenario. I realize that I could use application-level metrics (record
> counts, etc) as a proxy for this, but I’m working on providing a streaming
> platform and need all of my monitoring to be application agnostic.
>
> [image: cid:image001.png@01D5A059.19DB3EB0]
>
>
>
> I can’t find anything on it in the documentation.
>
>
>
> Thanks,
>
> Kelly
>
>

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