mco

Machine Config Operator

I'll write more when I have time.

Example

The following config can be found here

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfigPool
metadata:
  name: worker-bm
spec:
  machineConfigSelector:
    matchExpressions:
      - {key: machineconfiguration.openshift.io/role, operator: In, values: [worker,worker-bm]}
  nodeSelector:
    matchLabels:
      node-role.kubernetes.io/worker-bm: ""
---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker-bm
  name: 50-worker-bm
spec:
  config:
    ignition:
      config: {}
      security:
        tls: {}
      timeouts: {}
      version: 3.1.0
    networkd: {}
    passwd: {}
    storage:
      files:
        - path: "/etc/foo/foo.conf"
          filesystem: root
          mode: 420
          overwrite: true
          contents:
            source: data:;base64,UmVkIEhhdCBpcyBiZXR0ZXIgdGhhbiBWTXdhcmUhCg==
        - path: "/etc/foo/foo-other.conf"
          filesystem: root
          mode: 420
          overwrite: true
          contents:
            source: data:;base64,T3BlblNoaWZ0IGlzIHRoZSBiZXN0Cg==

Do an oc create of that file

oc create -f https://raw.githubusercontent.com/christianh814/openshift-toolbox/master/mco/examples/mcp-with-mc.yaml

Then label one of your nodes

oc label node  worker1.ocp4.example.com node-role.kubernetes.io/worker-bm=""

You'll see something like this

oc get nodes
NAME                       STATUS   ROLES              AGE   VERSION
master0.ocp4.example.com   Ready    master             50m   v1.16.2
master1.ocp4.example.com   Ready    master             50m   v1.16.2
master2.ocp4.example.com   Ready    master             50m   v1.16.2
worker0.ocp4.example.com   Ready    worker             50m   v1.16.2
worker1.ocp4.example.com   Ready    worker,worker-bm   50m   v1.16.2

Since worker1.ocp4.example.com matches both worker MCP and worker-bm, it'll get both MCPs. But since worker1.ocp4.example.com is the only one that matches worker-bm MCP. It's the only one with the /etc/foo/ contents.