Application Deployment (20%)¶

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.21
        ports:
        - containerPort: 80
        resources:
          requests:
            memory: "64Mi"
            cpu: "250m"
          limits:
            memory: "128Mi"
            cpu: "500m"

# Create deployment
kubectl create deployment nginx --image=nginx:1.21 --replicas=3

# Scale deployment
kubectl scale deployment nginx --replicas=5

# Update image
kubectl set image deployment/nginx nginx=nginx:1.22

# Edit deployment
kubectl edit deployment nginx

spec:
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%

spec:
  strategy:
    type: Recreate

# Check rollout status
kubectl rollout status deployment/nginx

# View rollout history
kubectl rollout history deployment/nginx

# View specific revision
kubectl rollout history deployment/nginx --revision=2

# Undo rollout (rollback)
kubectl rollout undo deployment/nginx

# Rollback to specific revision
kubectl rollout undo deployment/nginx --to-revision=2

# Pause rollout
kubectl rollout pause deployment/nginx

# Resume rollout
kubectl rollout resume deployment/nginx

# Restart deployment
kubectl rollout restart deployment/nginx

# Record the command in revision history
kubectl set image deployment/nginx nginx=nginx:1.22 --record

# Blue deployment (current)
apiVersion: apps/v1
kind: Deployment
metadata:
  name: app-blue
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
      version: blue
  template:
    metadata:
      labels:
        app: myapp
        version: blue
    spec:
      containers:
      - name: app
        image: myapp:v1
---
# Green deployment (new)
apiVersion: apps/v1
kind: Deployment
metadata:
  name: app-green
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
      version: green
  template:
    metadata:
      labels:
        app: myapp
        version: green
    spec:
      containers:
      - name: app
        image: myapp:v2
---
# Service - switch selector to change versions
apiVersion: v1
kind: Service
metadata:
  name: myapp-service
spec:
  selector:
    app: myapp
    version: blue  # Change to 'green' to switch
  ports:
  - port: 80
    targetPort: 8080

# Stable deployment (90% traffic)
apiVersion: apps/v1
kind: Deployment
metadata:
  name: app-stable
spec:
  replicas: 9
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: app
        image: myapp:v1
---
# Canary deployment (10% traffic)
apiVersion: apps/v1
kind: Deployment
metadata:
  name: app-canary
spec:
  replicas: 1
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - name: app
        image: myapp:v2
---
# Service routes to both (based on replica ratio)
apiVersion: v1
kind: Service
metadata:
  name: myapp-service
spec:
  selector:
    app: myapp  # Matches both deployments
  ports:
  - port: 80
    targetPort: 8080

# Add repository
helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update

# Search charts
helm search repo nginx
helm search hub wordpress

# Install chart
helm install my-nginx bitnami/nginx

# Install with custom values
helm install my-nginx bitnami/nginx -f values.yaml
helm install my-nginx bitnami/nginx --set service.type=NodePort

# List releases
helm list
helm list -A  # All namespaces

# Upgrade release
helm upgrade my-nginx bitnami/nginx --set replicaCount=3

# Rollback
helm rollback my-nginx 1

# Uninstall
helm uninstall my-nginx

# Show chart info
helm show values bitnami/nginx
helm show chart bitnami/nginx

mychart/
├── Chart.yaml          # Chart metadata
├── values.yaml         # Default configuration values
├── charts/             # Chart dependencies
├── templates/          # Template files
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── _helpers.tpl    # Template helpers
│   └── NOTES.txt       # Post-install notes
└── .helmignore         # Files to ignore

apiVersion: v2
name: mychart
description: A Helm chart for my application
type: application
version: 0.1.0
appVersion: "1.0.0"

replicaCount: 3

image:
  repository: nginx
  tag: "1.21"
  pullPolicy: IfNotPresent

service:
  type: ClusterIP
  port: 80

resources:
  limits:
    cpu: 100m
    memory: 128Mi
  requests:
    cpu: 100m
    memory: 128Mi

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Release.Name }}-deployment
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app: {{ .Release.Name }}
  template:
    metadata:
      labels:
        app: {{ .Release.Name }}
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
        ports:
        - containerPort: 80

├── base/
│   ├── deployment.yaml
│   ├── service.yaml
│   └── kustomization.yaml
└── overlays/
    ├── dev/
    │   └── kustomization.yaml
    └── prod/
        └── kustomization.yaml

# base/kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

resources:
  - deployment.yaml
  - service.yaml

# overlays/prod/kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

resources:
  - ../../base

namePrefix: prod-

replicas:
  - name: myapp
    count: 5

images:
  - name: myapp
    newTag: v2.0.0

patches:
  - patch: |-
      - op: replace
        path: /spec/template/spec/containers/0/resources/limits/memory
        value: 512Mi
    target:
      kind: Deployment
      name: myapp

# Preview output
kubectl kustomize overlays/prod/

# Apply
kubectl apply -k overlays/prod/

# Delete
kubectl delete -k overlays/prod/