Kubernetes configuration with yaml anchors

I have a deployment.yaml file and want to reuse the environment for all my deployments like this:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: beat
spec:
  selector:
    matchLabels:
      app: beat
  template:
    metadata:
      labels:
        app: beat
    spec:
      containers:
      - name: beat
        image: myimage
        command: ["celery", "-A", "wsgi.celery", "beat"]
        env: &default
        - name: FIRST_ENV
          value: my-value
        - name: SECOND_ENV
          value: another-value
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: flower
spec:
  selector:
    matchLabels:
      app: flower
  template:
    metadata:
      labels:
        app: flower
    spec:
      containers:
      - name: flower
        image: myimage
        command: ["celery", "flower", "-A", "wsgi.celery"]
        env: *defaultenv

But it seems like kubectl apply -f deployment.yaml won't work with YAML anchors.

error: error parsing deployment.yaml: error converting YAML to JSON: yaml: unknown anchor 'defaultenv' referenced

Is it possible to use YAML anchors or is there another preferred approach of how to reuse repeating blocks for k8s configuration?

YAML anchors are supported, but only for the same YAML file. You can't create the anchor (&) on a deployment file and reference (*) the value on another one.

If you want to share ENVs values across multiple Deployments, you can create a ConfigMap with the ENVs and use the envFrom spec. Example:

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-configmap
data:
  FIRST_ENV: my-value
  SECOND_ENV: another-value
---  
apiVersion: apps/v1
kind: Deployment
metadata:
  name: beat
spec:
  selector:
    matchLabels:
      app: beat
  template:
    metadata:
      labels:
        app: beat
    spec:
      containers:
      - name: beat
        image: myimage
        command: ["celery", "-A", "wsgi.celery", "beat"]
        envFrom:
        - configMapRef:
            name: my-configmap
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: flower
spec:
  selector:
    matchLabels:
      app: flower
  template:
    metadata:
      labels:
        app: flower
    spec:
      containers:
      - name: flower
        image: myimage
        command: ["celery", "flower", "-A", "wsgi.celery"]
        envFrom:
        - configMapRef:
            name: my-configmap

StackExchange DevOps Q#12837, answer score: 8