Ian Babrou created MESOS-3307:
---------------------------------
Summary: Configurable size of completed task / framework history
Key: MESOS-3307
URL: https://issues.apache.org/jira/browse/MESOS-3307
Project: Mesos
Issue Type: Bug
Reporter: Ian Babrou
We try to make Mesos work with multiple frameworks and mesos-dns at the same
time. The goal is to have set of frameworks per team / project on a single
Mesos cluster.
At this point our mesos state.json is at 4mb and it takes a while to assembly.
5 mesos-dns instances hit state.json every 5 seconds, effectively pushing
mesos-master CPU usage through the roof. It's at 100%+ all the time.
Here's the problem:
{noformat}
mesos λ curl -s http://mesos-master:5050/master/state.json | jq
.frameworks[].completed_tasks[].framework_id | sort | uniq -c | sort -n
1 "20150606-001827-252388362-5050-5982-0003"
16 "20150606-001827-252388362-5050-5982-0005"
18 "20150606-001827-252388362-5050-5982-0029"
73 "20150606-001827-252388362-5050-5982-0007"
141 "20150606-001827-252388362-5050-5982-0009"
154 "20150820-154817-302720010-5050-15320-0000"
289 "20150606-001827-252388362-5050-5982-0004"
510 "20150606-001827-252388362-5050-5982-0012"
666 "20150606-001827-252388362-5050-5982-0028"
923 "20150116-002612-269165578-5050-32204-0003"
1000 "20150606-001827-252388362-5050-5982-0001"
1000 "20150606-001827-252388362-5050-5982-0006"
1000 "20150606-001827-252388362-5050-5982-0010"
1000 "20150606-001827-252388362-5050-5982-0011"
1000 "20150606-001827-252388362-5050-5982-0027"
mesos λ fgrep 1000 -r src/master
src/master/constants.cpp:const size_t MAX_REMOVED_SLAVES = 100000;
src/master/constants.cpp:const uint32_t MAX_COMPLETED_TASKS_PER_FRAMEWORK =
1000;
{noformat}
Active tasks are just 6% of state.json response:
{noformat}
mesos λ cat ~/temp/mesos-state.json | jq -c . | wc
1 14796 4138942
mesos λ cat ~/temp/mesos-state.json | jq .frameworks[].tasks | jq -c . | wc
16 37 252774
{noformat}
I see four options that can improve the situation:
1. Add query string param to exclude completed tasks from state.json and use it
in mesos-dns and similar tools. There is no need for mesos-dns to know about
completed tasks, it's just extra load on master and mesos-dns.
2. Make history size configurable.
3. Make JSON serialization faster. With 10000s of tasks even without history it
would take a lot of time to serialize tasks for mesos-dns. Doing it every 60
seconds instead of every 5 seconds isn't really an option.
4. Create event bus for mesos master. Marathon has it and it'd be nice to have
it in Mesos. This way mesos-dns could avoid polling master state and switch to
listening for events.
All can be done independently.
Note to mesosphere folks: please start distributing debug symbols with your
distribution. I was asking for it for a while and it is really helpful:
https://github.com/mesosphere/marathon/issues/1497#issuecomment-104182501
Perf report for leading master:
!http://i.imgur.com/iz7C3o0.png!
I'm on 0.23.0.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
