Docker Stats blanked out when three containers ran for 30 minutes on Centos 7 host

Repro steps

  1. start Docker service on a Centos 7 VM with 11GB memory allocated
  2. from docker-compose, start three containers with mem_limit set to 2048m each, and use docker stats to monitor resource usage
  3. it ran well for 20 minutes or so, but after around 30 minutes, the “docker stats” command stopped reporting numbers, and I had to reboot the VM to get things back running again.

then 1-3 repeat

Any idea what might have caused this? Any logs I shall check to troubleshoot?