Set vm.max_map_count on cluster nodes

Question

I try to install ElasticSearch (latest) on a cluster nodes on Google Container Engine but ElasticSearch needs the variable : vm.max_map_count to be >= 262144.

Answer 1

As Robert pointed out, a DaemonSet could run as a startup script. Unfortunately, GKE will only let you run a DaemonSet with restartPolicy set as Always.

So in order to prevent k8s to continually restart the container after running sysctl, it has to sleep after the setup and preferably just run on selected nodes. It isn't an elegant solution, but it's elastic at least.

Example:

es-host-setup Dockerfile:

FROM alpine
CMD sysctl -w vm.max_map_count=262144; sleep 365d

DaemonSet resource file:

apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  name: es-host-setup
spec:
  template:
    metadata:
      labels:
        name: es-host-setup
    spec:
      containers:
      - name: es-host-setup
        image: es-host-setup
        securityContext:
          privileged: true
      restartPolicy: Always
      nodeSelector:
        pool: elasticsearch