Common Transformers

  • How can we use kustomize to modify and transform Kubernetes configs.

  • These are done using kustomize transformers.

    • Here, we will focus on a sub-group called common transformations.

  • In the following examples, we have these yaml files:

  • db-depl.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: api-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      component: api
  template:
    metadata:
      labels:
        component: api
    spec:
      containers:
        - name: nginx
          image: nginx
  • db-service.yaml:
apiVersion: v1
kind: Service
metadata:
  name: db-service
spec:
  selector:
    component: db-depl
  ports:
    - protocol: "TCP"
      port: 27017
      targetPort: 27017
  type: LoadBalancer

  • We want to apply a common configuration across all yaml files. For example, we want to add a label to each of the above yaml files for org: KodeKloud

  • Or even append -dev to the end of api-deployment as an example.

  • We can easily make common configuration changes across all Kubernetes resources.

  • Types of Common Transformations:

    • commonLabel - adds a label to all Kubernetes resources.

    • namePrefix/Suffix - adds a common prefix-suffix to all resource names.

    • Namespace - adds a common namespace to all resources.

    • commonAnnotations - adds an annotation to all resources.

  • Regarding the commonLabel transformer.

    • We want to add a label to all resources.

    • Go into the Kustomization.yaml file and add the following:

commonLabels:
  org: KodeKloud

* The above then adds the label to all Kubernetes resources.

  • Namespace Transformer.

    • Puts all Kubernetes resources under a particular namespace.

      • This looks like this: namespace: lab

  • For the Prefix/suffix Transformer, can add in the following:

namePrefix: KodeKloud-
nameSuffix: -dev

* This will map to the prefix of the name and the suffix of the name as well.

  • CommonAnnotations Transformer

    • If you want to add commonAnnotations, add the following lines:
commonAnnotations:
  branch: master
  • This will then be added to all Kubernetes objects.

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