Kubernetes Deployment

# Kubernetes Deployment

## Table of Contents

- [Overview](#overview)
- [When to Use](#when-to-use)
- [Quick Start](#quick-start)
- [Reference Guides](#reference-guides)
- [Best Practices](#best-practices)

## Overview

Master Kubernetes deployments for managing containerized applications at scale, including multi-container services, resource allocation, health checks, and rolling deployment strategies.

## When to Use

- Container orchestration and management
- Multi-environment deployments (dev, staging, prod)
- Auto-scaling microservices
- Rolling updates and blue-green deployments
- Service discovery and load balancing
- Resource quota and limit management
- Pod networking and security policies

## Quick Start

Minimal working example:

```yaml
# kubernetes-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: api-service
  namespace: production
  labels:
    app: api-service
    version: v1
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  selector:
    matchLabels:
      app: api-service
  template:
    metadata:
      labels:
        app: api-service
        version: v1
      annotations:
// ... (see reference guides for full implementation)
```

## Reference Guides

Detailed implementations in the `references/` directory:

| Guide | Contents |
|---|---|
| [Complete Deployment with Resource Management](references/complete-deployment-with-resource-management.md) | Complete Deployment with Resource Management |
| [Deployment Script](references/deployment-script.md) | Deployment Script |
| [Service Account and RBAC](references/service-account-and-rbac.md) | Service Account and RBAC |

## Best Practices

### ✅ DO

- Use resource requests and limits
- Implement health checks (liveness, readiness)
- Use ConfigMaps for configuration
- Apply security context restrictions
- Use service accounts and RBAC
- Implement pod anti-affinity
- Use namespaces for isolation
- Enable pod security policies

### ❌ DON'T

- Use latest image tags in production
- Run containers as root
- Set unlimited resource usage
- Skip readiness probes
- Deploy without resource limits
- Mix configurations in container images
- Use default service accounts


# Complete Deployment with Resource Management

## Complete Deployment with Resource Management

```yaml
# kubernetes-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: api-service
  namespace: production
  labels:
    app: api-service
    version: v1
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  selector:
    matchLabels:
      app: api-service
  template:
    metadata:
      labels:
        app: api-service
        version: v1
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "8080"
    spec:
      # Service account for RBAC
      serviceAccountName: api-service-sa

      # Security context
      securityContext:
        runAsNonRoot: true
        runAsUser: 1000
        fsGroup: 1000

      # Pod scheduling
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
            - weight: 100
              podAffinityTerm:
                labelSelector:
                  matchExpressions:
                    - key: app
                      operator: In
                      values:
                        - api-service
                topologyKey: kubernetes.io/hostname

      # Pod termination grace period
      terminationGracePeriodSeconds: 30

      # Init containers
      initContainers:
        - name: wait-for-db
          image: busybox:1.35
          command:
            [
              "sh",
              "-c",