Hi all,
I sketched a little doc [1] about this subject. It tries to sum up the
differences between the runners towards metrics extraction and propose
some possible designs to have a runner agnostic extraction of the metrics.
It is a 2 pages long doc, can you please comment it, and correct it if
needed?
Thanks
Etienne
[1]: *https://s.apache.org/runner_independent_metrics_extraction*
Le 27/11/2017 à 18:17, Ben Chambers a écrit :
I think discussing a runner agnostic way of configuring how metrics are
extracted is a great idea -- thanks for bringing it up Etienne!
Using a thread that polls the pipeline result relies on the program that
created and submitted the pipeline continuing to run (eg., no machine
faults, network problems, etc.). For many applications, this isn't a good
model (a Streaming pipeline may run for weeks, a Batch pipeline may be
automatically run every hour, etc.).
Etienne's proposal of having something the runner pushes metrics too has
the benefit of running in the same cluster as the pipeline, thus having the
same reliability benefits.
As noted, it would require runners to ensure that metrics were pushed into
the extractor but from there it would allow a general configuration of how
metrics are extracted from the pipeline and exposed to some external
services.
Providing something that the runners could push metrics into and have them
automatically exported seems like it would have several benefits:
1. It would provide a single way to configure how metrics are actually
exported.
2. It would allow the runners to ensure it was reliably executed.
3. It would allow the runner to report system metrics directly (eg., if a
runner wanted to report the watermark, it could push that in directly).
-- Ben
On Mon, Nov 27, 2017 at 9:06 AM Jean-Baptiste Onofré <[email protected]>
wrote:
Hi all,
Etienne forgot to mention that we started a PoC about that.
What I started is to wrap the Pipeline creation to include a thread that
polls
periodically the metrics in the pipeline result (it's what I proposed when
I
compared with Karaf Decanter some time ago).
Then, this thread marshalls the collected metrics and send to a sink. At
the
end, it means that the harvested metrics data will be store in a backend
(for
instance elasticsearch).
The pro of this approach is that it doesn't require any change in the
core, it's
up to the user to use the PipelineWithMetric wrapper.
The cons is that the user needs to explicitly use the PipelineWithMetric
wrapper.
IMHO, it's good enough as user can decide to poll metrics for some
pipelines and
not for others.
Regards
JB
On 11/27/2017 04:56 PM, Etienne Chauchot wrote:
Hi all,
I came by this ticket https://issues.apache.org/jira/browse/BEAM-2456.
I know
that the metrics subject has already been discussed a lot, but I would
like to
revive the discussion.
The aim in this ticket is to avoid relying on the runner to provide the
metrics
because they don't have all the same capabilities towards metrics. The
idea in
the ticket is to still use beam metrics API (and not others like
codahale as it
has been discussed some time ago) and provide a way to extract the
metrics with
a polling thread that would be forked by a PipelineWithMetrics (so,
almost
invisible to the end user) and then to push to a sink (such as a Http
rest sink
for example or Graphite sink or anything else...). Nevertheless, a
polling
thread might not work for all the runners because some might not make the
metrics available before the end of the pipeline. Also, forking a thread
would
be a bit unconventional, so it could be provided as a beam sdk extension.
Another way, to avoid polling, would be to push metrics values to a sink
when
they are updated but I don't know if it is feasible in a runner
independent way.
WDYT about the ideas in this ticket?
Best,
Etienne
--
Jean-Baptiste Onofré
[email protected]
http://blog.nanthrax.net
Talend - http://www.talend.com
