-What to do/check/debug/root cause analysis when jobtracker hang
Lately, jobtracker in one of our production cluster fall into hang state.
The load 5,10,15min is like 1 ish;
with top command, jobtracker has 100% cpu all the time.
So, i went ahead to try top -H -p jobtracker_pid, and always see a
thread that have 100% cpu all the time.
Unless we restart jobtracker, the hang state would never go away.
I found OOM in jobtracker log file during the hang state.
how could i know what is really going on on the one and only one
thread that has 100% cpu.
how could i prove that we run out of memory because amount of job
there is memory leak in application side. ?
I tried jstack to dump, and http://jobtracker:50030/stacks
i just don't know what I should really look at output of those commands.
The cluster is cdh3u4, on Centos6.2, with disable transparent_hugepage.
hopefully this make sense,