Autotune memory and cpu use based on Kubernetes pod limits for skupper-router container

[jiridanek]

• This is how Java does it, regarding heap size adjustment based on available RAM JDK-8146115 : Improve docker container detection and resource configuration usage.

  • The implementation should be in the cgroup*.cpp files under https://github.com/openjdk/jdk/tree/master/src/hotspot/os/linux
  • Not sure if both Cgroups V1 and V2 need to be supported nowadays, or if V2 is enough.

• Kubernetes CPU requests explained

  • https://github.com/mechpen/tgtop
  • # cat /sys/fs/cgroup/cpu/kubepods/cpu.shares
  • # cat /sys/fs/cgroup/cpu/kubepods/<pod_foo>/<container_foo>/cpu.shares
  • # cat /sys/fs/cgroup/cpuset/kubepods/<pod_foo>/<container_foo>/cpuset.cpus
    • /cpuacct.usage
  • /sys/fs/cgroup/memory/memory.limit_in_bytes, /sys/fs/cgroup/memory/memory.usage_in_bytes

• https://stackoverflow.com/questions/57731048/kubernetes-get-actual-resource-limits-inside-containersays it is possible to use something called the Downward API to reflect the memory and cpu limits in env variables of the pod