cluster-bootstrap-controller

cluster-bootstrap-controller

This is a controller that tracks CAPI Cluster objects.

It provides a CR for a ClusterBootstrapConfig which provides a Job template.

When a CAPI Cluster is "provisioned" a Job is created from the template, the template can access multiple fields.

apiVersion: capi.weave.works/v1alpha1
kind: ClusterBootstrapConfig
metadata:
  name: clusterbootstrapconfig-sample
  namespace: default
spec:
  clusterSelector:
    matchLabels:
      demo: "true"
  jobTemplate:
    generateName: 'run-wego-{{ .ObjectMeta.Name }}'
    spec:
      containers:
      - image: alpine:latest
        name: cat-kubeconfig
        volumeMounts:
        - name: kubeconfig
          mountPath: "/etc/wego"
          readOnly: true
        command: ["cat", "/etc/wego/value"]
      restartPolicy: Never
      volumes:
      - name: kubeconfig
        secret:
          secretName: '{{ .ObjectMeta.Name }}-kubeconfig'

This is using Go templating and the Cluster object is provided as the context, this means that expressions like {{ .ObjectMeta.Name }} will get the name of the Cluster that has transitioned to "provisioned".

Annotations

Go templating doesn't easily support access to strings that have "/" in them, which is a common annotation naming strategy.

The templating provides a function called "annotation", this can accept a string annotation which can access an annotation.

e.g.

      volumes:
      - name: kubeconfig
        secret:
          secretName: '{{ annotation "example.com/secret-name }}'