faysilalshareef/kubernetes

Kubernetes — Deployment Manifests

Core Principles

• Per-environment manifests: dev-manifest.yaml, staging-manifest.yaml, prod-manifest.yaml
• Token placeholders (#{TOKEN}#) replaced during CI/CD deployment
• Health check probes: /health/ready (readiness), /health/live (liveness)
• RollingUpdate strategy with maxUnavailable: 0, maxSurge: 1
• Environment variables from Secrets and ConfigMaps
• Service Bus topics/subscriptions configured via environment

Key Patterns

Deployment Manifest

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {domain}-command
  namespace: {company}-{env}
spec:
  replicas: #{REPLICAS}#
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 0
      maxSurge: 1
  selector:
    matchLabels:
      app: {domain}-command
  template:
    metadata:
      labels:
        app: {domain}-command
    spec:
      containers:
        - name: {domain}-command
          image: #{ACR_NAME}#.azurecr.io/{domain}-command:#{IMAGE_TAG}#
          ports:
            - containerPort: 8080
            - containerPort: 8081
          env:
            - name: ASPNETCORE_ENVIRONMENT
              value: "#{ENVIRONMENT}#"
            - name: ConnectionStrings__DefaultConnection
              valueFrom:
                secretKeyRef:
                  name: {domain}-secrets
                  key: db-connection-string
            - name: ServiceBus__ConnectionString
              valueFrom:
                secretKeyRef:
                  name: {domain}-secrets
                  key: servicebus-connection
            - name: ExternalServices__QueryServiceUrl
              value: "http://{domain}-query:8081"
          readinessProbe:
            httpGet:
              path: /health/ready
              port: 8080
            initialDelaySeconds: 10
            periodSeconds: 15
          livenessProbe:
            httpGet:
              path: /health/live
              port: 8080
            initialDelaySeconds: 30
            periodSeconds: 30
          resources:
            requests:
              cpu: 100m
              memory: 256Mi
            limits:
              cpu: 500m
              memory: 512Mi

Service

apiVersion: v1
kind: Service
metadata:
  name: {domain}-command
  namespace: {company}-{env}
spec:
  selector:
    app: {domain}-command
  ports:
    - name: http
      port: 8080
      targetPort: 8080
    - name: grpc
      port: 8081
      targetPort: 8081
  type: ClusterIP

Secret (Template)

apiVersion: v1
kind: Secret
metadata:
  name: {domain}-secrets
  namespace: {company}-{env}
type: Opaque
stringData:
  db-connection-string: "#{DB_CONNECTION_STRING}#"
  servicebus-connection: "#{SERVICEBUS_CONNECTION}#"

ConfigMap

apiVersion: v1
kind: ConfigMap
metadata:
  name: {domain}-config
  namespace: {company}-{env}
data:
  Serilog__SeqUrl: "http://seq:5341"
  Serilog__WriteToConsole: "true"

Anti-Patterns

| Anti-Pattern | Correct Approach | |---|---| | Secrets in ConfigMap | Use Secret for sensitive data | | No resource limits | Set requests and limits for stability | | Missing health probes | Add readiness and liveness probes | | Hardcoded image tags | Use token placeholders for CI/CD | | maxUnavailable > 0 | Zero downtime: maxUnavailable=0, maxSurge=1 |

Detect Existing Patterns

# Find K8s manifests
find . -name "*-manifest.yaml" -o -name "*.k8s.yaml" | head -10

# Find token placeholders
grep -r "#{.*}#" --include="*.yaml" .

# Find health check endpoints
grep -r "/health" --include="*.cs" src/

Adding to Existing Project

1. Follow existing manifest naming — {env}-manifest.yaml
2. Match namespace convention — {company}-{env}
3. Use existing secret names for shared resources
4. Add inter-service URLs via environment variables
5. Configure health probes matching the application health endpoints