Docker and ram usage

Question

I have a swarm cluster with 24Gb of RAM on each nodes.

Free -g shows 6Gb used but I get some OutMemory errors on some java or elasticsearch containers.

  total used free shared buff/cache available Mem: 23 6 6 0 10 16 Swap: 1 0 1 

I removed all reservation or limits on containers

Any idea what causes the OutOfMermory ? I did set Xmx on the containers and they are not using to much RAM...

Thanks a lot

Answer 1

I found the problem.

It was a kernel configuration in the sysctl.conf.

I had this :

cat /etc/sysctl.conf |grep vm.
vm.swappiness=10
vm.overcommit_memory=2
vm.dirty_ratio=2
vm.dirty_background_ratio=1

I removed everything setted for DB2 (put back the default configuration) and now I can take advantage of all the RAM of the hosts.

I kept this :

cat /etc/sysctl.conf |grep vm.
vm.swappiness=10
vm.max_map_count=262144

Thanks