App Timeline Web Server UI becomes unreachable/connection failed after enabling DEBUG on Yarn

[#1]

Ambari alerts this message: "Connection failed to https://domain.com:8188/blah/blah"

or

"App Timeline Server Web UI is unreachable"

when debug mode is enabled on Yarn > Configs > Advanced > Advanced yarn-env > yarn-env template

export YARN_ROOT_LOGGER=${YARN_ROOT_LOGGER:-DEBUG,EWMA,RFA}

Is this a bug on ambari or Yarn? Is there a fix for this?

----- Cluster Versions

Ambari 2.2.1.0

HDP 2.3.4.7-4

[#2]

@John Ross Tasipit, can you please check Timeline server logs to check why is it going down ?

[#3]

@John Ross Tasipit

There is a rare possibility that this is a BUG. Please check ATS daemon logs to see why it went down or crashing. Maybe it was not restarted properly or died suddenly. Logs should give you more hint.

If you need any further help, you can paste error logs in this thread.

[#4]

What path does ATS daemon logs located?