Allow the use of init containers in the deployment config

[curtdept]

So I can set thing like transparent hugepage settings, vm.max_map_count, etc prior to container start.

I see some initContainers already there, there just doesnt seem to be a way to append to it.

A shortcut flag that auto applies recommended config in an init would also be helpful.

[iMoses]

+1

There's no way to address Max Memory Mappings without creating my own custom images.
Please support passing initContainer config.

[curtdept]

Wordaround atm with a DaemonSet use a nodeselector to limit to the nodes you want to change.

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: sysctl
  namespace: arango
spec:
  selector:
    matchLabels:
      app: sysctl
  template:
    metadata:
      labels:
        app: sysctl
    spec:
      hostNetwork: yes
      initContainers:
      - name: sysctl
        image: "busybox"
        securityContext:
          privileged: true
        command: ['sh', '-c', 'sysctl -w vm.max_map_count=256000 && echo madvise > /sys/kernel/mm/transparent_hugepage/enabled && echo madvise > /sys/kernel/mm/transparent_hugepage/defrag']
      containers:
        - name: sleep
          image: filefrog/k8s-hacks:pause

[ajanikow]

Hello!

Fixed with PR #650

Best Regards,
Adam.

[curtdept]

@ajanikow if I read this right, just initContainers under the appropriate servergroup?

ie.

spec:
  agents:
    initContainers:
      - name: sysctl
    image: busybox
    securityContext:
      privileged: true
    command:
      - sh

Going to update the docs with an example?

[iMoses]

@ajanikow if I read this right, just initContainers under the appropriate servergroup?

@curtdept You actually have to dig deep in the code to figure how the new mechanism works.

Under the service group you can add:

initContainers:
  mode: update  // weather to recreate pods on changes to initContainers, can also be "ignore"
  containers:
    - name: sysctl
      image: busybox
      securityContext:
        privileged: true
      command: ['sh', '-c', 'sysctl -w vm.overcommit_memory=0 vm.max_map_count=262144']

I really wish it was documented or at the very least had tests or an example, it took me quite a while to find.

[ajanikow]

Hello!

Documentation is updated in docs repository, changes should be propagated soon.

Best,
Adam.

[curtdept]

Awesome, will create new issue if needed :) Closing this for now.