Why container orchestration matters in Kubernetes - See It in Action

Why Container Orchestration Matters

📖 Scenario: You are working in a team that deploys applications using containers. As the number of containers grows, managing them manually becomes hard. You want to learn how container orchestration helps to automate and simplify this process.

🎯 Goal: Build a simple Kubernetes setup that shows how container orchestration manages multiple containers automatically.

📋 What You'll Learn

Create a Kubernetes deployment with multiple replicas

Add a label selector to manage pods

Use a service to expose the deployment

Display the status of pods managed by the deployment

💡 Why This Matters

🌍 Real World

Container orchestration is used in real companies to manage many containers running applications, so they stay healthy and available without manual work.

💼 Career

Understanding container orchestration with Kubernetes is a key skill for DevOps engineers and cloud professionals who deploy and maintain applications at scale.

1

Create a Deployment YAML

Create a Kubernetes deployment YAML file named deployment.yaml with these exact values: apiVersion: apps/v1, kind: Deployment, metadata.name: myapp-deployment, spec.replicas: 3, and a container named myapp-container using the image nginx:latest.

Kubernetes

# Your code here

Need a hint?

Use the Kubernetes deployment structure with replicas: 3 and the nginx:latest image.

2

Add Label Selector

Add a label selector under spec.selector.matchLabels with the label app: myapp to the deployment.yaml file. Also add the same label under spec.template.metadata.labels.

Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp-container
        image: nginx:latest
# Your code here

Need a hint?

Labels help Kubernetes know which pods belong to this deployment.

3

Create a Service YAML

Create a Kubernetes service YAML file named service.yaml that exposes the deployment. Use apiVersion: v1, kind: Service, metadata.name: myapp-service, spec.selector.app: myapp, and expose port 80 on the service and target port 80 on the pods.

Kubernetes

# Your code here

Need a hint?

The service connects to pods with label app: myapp and exposes port 80.

4

Display Pod Status

Run the command kubectl get pods -l app=myapp --no-headers -o custom-columns=NAME:.metadata.name,STATUS:.status.phase to display the names and statuses of pods with label app=myapp.

Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp-container
        image: nginx:latest

---

apiVersion: v1
kind: Service
metadata:
  name: myapp-service
spec:
  selector:
    app: myapp
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80

# Run the command below to show pod names and statuses
# Your code here

Need a hint?

This command lists pods with label app=myapp and shows their status.