kubernetes

Kubernetes (K8s)

Kubernetes is the industry-standard container orchestration platform, featuring declarative configuration, horizontal scaling, native sidecar containers, and advanced Gateway API traffic routing.

When to Use

• Container Orchestration at Scale: Automating deployment, scaling, networking, and lifecycle of containerized services.
• Self-Healing Infrastructure: Automated container restarts, rescheduling dead nodes, and rolling zero-downtime updates.
• Dynamic Horizontal Pod Autoscaling (HPA): Scaling replica counts dynamically based on CPU, memory, or custom metrics.
• Multi-Tenant Workload Isolation: Dividing cluster resources safely using Namespaces, RBAC, and NetworkPolicies.

Quick Start

# Gateway (The Load Balancer)
apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: my-gateway
spec:
  gatewayClassName: nginx
  listeners:
    - name: http
      protocol: HTTP
      port: 80

---
# HTTPRoute (The Routing Rule)
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: my-app
spec:
  parentRefs:
    - name: my-gateway
  rules:
    - matches:
        - path:
            type: PathPrefix
            value: /api
      backendRefs:
        - name: my-service
          port: 8080

Core Concepts

Production Deployment Manifest with Probes & Resource Limits

Deploying resilient stateless applications:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: api-service
  namespace: production
  labels:
    app.kubernetes.io/name: api-service
    app.kubernetes.io/part-of: core-platform
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  selector:
    matchLabels:
      app: api-service
  template:
    metadata:
      labels:
        app: api-service
    spec:
      securityContext:
        runAsNonRoot: true
        runAsUser: 10001
        fsGroup: 10001
      containers:
        - name: server
          image: registry.example.com/api-service:v2.1.0
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 8080
          resources:
            requests:
              cpu: "250m"
              memory: "256Mi"
            limits:
              cpu: "1000m"
              memory: "512Mi"
          readinessProbe:
            httpGet:
              path: /healthz/ready
              port: 8080
            initialDelaySeconds: 5
            periodSeconds: 5
          livenessProbe:
            httpGet:
              path: /healthz/live
              port: 8080
            initialDelaySeconds: 15
            periodSeconds: 10