Demo DeploymentConfigDeployment

1. As a standard Kubernetes Deployment (apps/v1).
2. As an OpenShift DeploymentConfig (apps.openshift.io/v1).

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1) Deploy CartsDB as a Kubernetes Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: carts-db
  labels:
    name: carts-db
spec:
  replicas: 1
  selector:
    matchLabels:
      name: carts-db
  template:
    metadata:
      labels:
        name: carts-db
    spec:
      containers:
      - name: carts-db
        image: centos/mongodb-34-centos7
        ports:
        - name: mongo
          containerPort: 27017
        env:
        - name: MONGODB_USER
          value: sock-user
        - name: MONGODB_PASSWORD
          value: password
        - name: MONGODB_DATABASE
          value: data
        - name: MONGODB_ADMIN_PASSWORD
          value: admin
        volumeMounts:
        - mountPath: /tmp
          name: tmp-volume
      volumes:
      - name: tmp-volume
        emptyDir:
          medium: Memory
      nodeSelector:
        beta.kubernetes.io/os: linux

• Runs one replica of the MongoDB container and exposes port 27017.
• Provides environment variables for credentials and the database name.
• Mounts an in-memory emptyDir at /tmp.
• Pins the Pod to Linux nodes with nodeSelector.

• OpenShift will create a ReplicaSet that in turn manages the Pod(s).
• The console shows Deployment metadata (name, namespace, labels, update strategy, selector), and provides convenient inspection of Pods, env vars, volumes, and events.

• ReplicaSet presence and Pod count.
• Pod events and container logs for startup validation.
• Container environment variables and mounted volumes.

• The web console is great for inspection and monitoring, but avoid making transient/manual edits directly in the console unless you intend those changes to be permanent. Manifests from source control, CI/CD, or GitOps will typically overwrite manual edits.

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2) Delete the Deployment and create a DeploymentConfig

apiVersion: apps.openshift.io/v1
kind: DeploymentConfig
metadata:
  name: carts-db
  labels:
    name: carts-db
spec:
  replicas: 1
  template:
    metadata:
      labels:
        name: carts-db
    spec:
      containers:
      - name: carts-db
        image: centos/mongodb-34-centos7
        ports:
        - name: mongo
          containerPort: 27017
        env:
        - name: MONGODB_USER
          value: sock-user
        - name: MONGODB_PASSWORD
          value: password
        - name: MONGODB_DATABASE
          value: data
        - name: MONGODB_ADMIN_PASSWORD
          value: admin
        volumeMounts:
        - mountPath: /tmp
          name: tmp-volume
      volumes:
      - name: tmp-volume
        emptyDir:
          medium: Memory
      nodeSelector:
        beta.kubernetes.io/os: linux

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Key differences: Deployment vs DeploymentConfig

• Deployments are the Kubernetes standard for managing replicated Pods and rolling updates.
• DeploymentConfigs are useful when you require OpenShift integrations (for example, automatic redeploys from internal image builds via imageChange triggers).

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Best practices and recommendations

• Manage manifests in source control and deploy via CI/CD or GitOps for consistency and auditability.
• Use the OpenShift console to monitor, inspect events, and debug—but commit desired manifest changes back to source control rather than editing ad-hoc in the console.
• Prefer stable node labels (kubernetes.io/os: linux) for portability across clusters.

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Summary

• Deployments (apps/v1) are the recommended, portable Kubernetes primitive and create ReplicaSets.
• DeploymentConfigs (apps.openshift.io/v1) are OpenShift-specific and create ReplicationControllers; they add features integrated with OpenShift builds and image workflows.
• Use the console for visualization and quick debugging; manage definitive configuration through versioned manifests and CI/CD.

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Links and references

• Kubernetes Deployments (official docs)
• OpenShift DeploymentConfig (official docs)
• OpenShift Console — Workloads