I’ve done this with Gitlab as my Docker registry.

Create a secret of type docker-registry:

kubectl create secret docker-registry gitlab-registry --docker-email="EMAIL" --docker-username="USERNAME" --docker-server="https://registry.gitlab.com/" --docker-password="PASSWORD"

My deployment spec:

spec:
  replicas: 1
  selector:
    matchLabels:
      app: deploymentName
  template:
    metadata:
      labels:
        app: deploymentName
    spec:
      containers:
      - name: deploymentName
        image: registry.gitlab.com/group/repo:0.9.0
        ports:
        - containerPort: 8080
      imagePullSecrets:
      - name: gitlab-registry

Hope that helps!