Hi!
We are looking into options to integrate Apache Flink's monitoring web
frontend with the YARN Timeline Server. Flink has its own web frontend for
monitoring and analyzing running jobs. The web frontend shows a lot of
Flink specific stuff, in addition to tast start and end times.
When Flink runs on YARN, the web frontend server lives as part of the App
Master, and its metrics are kept only on the App Master. The metrics and
web frontend are gone once the job finishes and the App Master quits.
I am wondering now is we could store Flink's monitoring data in the YARN
Timeline Server and visualize it from there, to make past job's data
accessible.
I have seen that the Timeline Server allows applications to store some
generic data. I have not fully understood what it allows, though.
To illustrate what we are looking for, let me give you a bit of background
into how Flink's web frontend is structured.
Flink's web frontend is structured in a very simple way, so that after a
job is done, no dynamic data or handlers are needed on the server side any
more. Everything is static files and JSON objects, at specific relative URLs
(1) A set of static HTML / JS / CSS files that implement the visualization
(2) Some JSON objects with static data (once the job is complete), under
pre-defined URL.
For example, the path
"<app-id-root>/jobs/7684be6004e4e955c2a558a9bc463f65/exception" would
return the static response '{ "root-exception": "java.io.IOException: File
already exists:/tmp/abzs/2\n\tat
org.apache.flink.core.fs.local.LocalFileSystem. ...", ...}'
In some sense, what this would need is a Key/Value store where the key is a
URL and the value is a JSON object or small file.
A post-run hook in Flink would call a set of POST requests to store the
JSON objects and files under the URLs. That's it. Calling the index.html
then at the specific URL of that job would run Flink's rendering of the
job's metrics and times.
I know it is a bit of a long shot, but would the timeline server support
something like this?
Greetings,
Stephan
