• Manage application updates smoothly.

• Rollback failed deployments to ensure service continuity.

• Understand and manage image streams and use triggers for automatic updates.

Task 1: Update an Application and Monitor the Rollout Status

Objective: Demonstrate the process of updating an application and monitoring the rollout status.

Explanation: Regularly updating applications is crucial for incorporating new features, bug fixes, and security patches. Monitoring the rollout status helps ensure a smooth and controlled update process

Create a deployment config file name it task1.yaml:

apiVersion: apps/v1  
kind: Deployment
metadata:
  name: myapp-deployment
  namespace: labs
  labels:
    app: myapp
spec:  
  replicas: 2  
  selector:
    matchLabels:
      app: myapp
      type: front-end
  template:
    metadata:
      labels:
        app: myapp
        type: front-end
    spec: 
      containers:
      - name: my-container
        image: nginx:1.71 # choose one that is not deprecated version of nginx

oc create -f task1.yaml

To update the application using a new container image:

oc set image deployment/myapp-deployment my-container=nginx:latest

You can monitor the roll-out status too:

oc rollout status deployment myapp-deployment

Task 2: Simulate a Failed Deployment and Perform a Rollback

Objective: Illustrate the simulation of a failed deployment and the subsequent rollback process.

Explanation: Simulating a failed deployment allows participants to practice rollback procedures, ensuring that, in a real-world scenario, service continuity can be quickly restored in case of issues.

# Simulating a failed deployment (incorrect image)
oc set image deployment/myapp-deployment my-container=nginx:5

If you see any problem with the application, you would want to roll back to the previous or stable version:

oc rollout undo deployment/myapp-deployment

Task 3: Create and Manage an Image Stream and Set Up Triggers for Automated Deployments

Objective: Demonstrate the creation and management of an ImageStream and the setup of triggers for automated deployments.

Explanation: ImageStreams help manage the flow of container images within OpenShift, allowing for versioning and control. Triggers automate the deployment process based on changes to the associated image.

Create a task3.yaml:

apiVersion: image.openshift.io/v1
kind: ImageStream
metadata:
  name: my-app-image-stream
spec:
  tags:
  - name: latest
    from:
      kind: DockerImage
      name: quay.io/redhattraining/hello-world-nginx:v1.0
    importPolicy:
      scheduled: true

oc create -f task3.yaml