[MESOS-3307] Configurable size of completed task / framework history

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.24.2, 0.25.1, 0.26.1, 0.27.0
• Labels: mesosphere
• Sprint: Mesosphere Sprint 26
• Story Points: 3
• Assignee: Kevin Klues
• Reporter: Ivan Babrou
• Shepherd: Benjamin Mahler
• Created: 24/Aug/15 16:50
• Updated: 26/Nov/18 12:21
• Resolved: 26/Nov/18 12:21

Description

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:

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;

Active tasks are just 6% of state.json response:

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

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:

I'm on 0.23.0.