Issue with Jenkins Deployment File: Unknown resource kind: Deployment

Question

I'm struggling to figure out what the solution might be, so I thought to ask here. I'm trying to use the code below to deploy a Jenkins pod to Kubernetes, but it fails with a Unknown resource kind: Deployment error:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: jenkins-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: jenkins
  template:
    metadata:
      labels:
        app: jenkins
    spec:
      containers:
        - name: jenkins
          image: jenkins/jenkins:lts-alpine
          ports:
            - name: http-port
              containerPort: 8080
          volumeMounts:
            - name: jenkins-home
              mountPath: /var/jenkins_home
      volumes:
        - name: jenkins-home
          emptyDir: {}

The output of kubectl api-versions is:

admissionregistration.k8s.io/v1
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1
apiregistration.k8s.io/v1beta1
apps/v1
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
autoscaling/v2beta2
batch/v1
batch/v1beta1
certificates.k8s.io/v1beta1
coordination.k8s.io/v1
coordination.k8s.io/v1beta1
discovery.k8s.io/v1beta1
events.k8s.io/v1beta1
extensions/v1beta1
networking.k8s.io/v1
networking.k8s.io/v1beta1
node.k8s.io/v1beta1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
scheduling.k8s.io/v1
scheduling.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1

Does anyone know what the problem might be? If this is an indentation issue, I'm failing to see it.

Answer 1

It seems the apiVersion is deprecated. You can simply convert to current apiVersion and apply.

$ kubectl convert -f jenkins-dep.yml          
kubectl convert is DEPRECATED and will be removed in a future version.
In order to convert, kubectl apply the object to the cluster, then kubectl get at the desired version.
apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: jenkins
  name: jenkins-deployment
spec:
  progressDeadlineSeconds: 2147483647
  replicas: 1
  revisionHistoryLimit: 2147483647
  selector:
    matchLabels:
      app: jenkins
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: jenkins
    spec:
      containers:
      - image: jenkins/jenkins:lts-alpine
        imagePullPolicy: IfNotPresent
        name: jenkins
        ports:
        - containerPort: 8080
          name: http-port
          protocol: TCP
        resources: {}
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
        volumeMounts:
        - mountPath: /var/jenkins_home
          name: jenkins-home
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30
      volumes:
      - emptyDir: {}
        name: jenkins-home
status: {}

---

$ kubectl convert -f jenkins-dep.yml -oyaml > jenkins-dep-latest.yml

Answer 2

Change the apiVersion from extensions/v1beta1 to apps/v1 and use kubectl version to check if the kubectl client and kube API Server version is matching and not too old.