100-Days-Of-DevOps-Challenge-KodeKloud

Deploy Applications with Kubernetes Deployments

The Nautilus DevOps team is delving into Kubernetes for app management. One team member needs to create a deployment following these details:

Create a deployment named nginx to deploy the application nginx using the image nginx:latest (ensure to specify the tag)

Note: The kubectl utility on jump_host is set up to interact with the Kubernetes cluster.

Steps

Let’s create the k3s-deployment.yml file with these contents:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
  labels:
    app: nginx

spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: nginx
          image: nginx:latest
          ports:
          - containerPort: 80

• Run the following commands to create the deployment:

  kubectl apply -f k3s-deployment.yml
  

• Verify Deployments

  kubectl get deployments.apps
  

Good to Know?

Kubernetes Deployments

• Purpose: Manage stateless applications with declarative updates
• ReplicaSets: Deployments create and manage ReplicaSets
• Rolling Updates: Zero-downtime application updates
• Rollback: Easy rollback to previous versions

Deployment Components

• Selector: Matches pods using labels
• Replicas: Desired number of pod instances
• Template: Pod specification for creating instances
• Strategy: Update strategy (RollingUpdate, Recreate)

Labels and Selectors

• Labels: Key-value pairs attached to objects
• Selectors: Query labels to identify objects
• Loose Coupling: Flexible object relationships
• Organization: Group and categorize resources

Best Practices

• Resource Limits: Set CPU and memory limits
• Health Checks: Configure liveness and readiness probes
• Image Tags: Use specific tags, avoid ‘latest’
• Naming: Use descriptive names for resources

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