Kubernetes for PHP Developers

Also Known As

TL;DR

Explanation

Key Kubernetes resources for PHP: Pod (one PHP-FPM container + nginx sidecar), Deployment (manages pod replicas, rolling updates, rollbacks), Service (stable DNS name for pods — ClusterIP for internal, LoadBalancer for external), ConfigMap (non-secret config — php.ini settings), Secret (sensitive config — DB passwords, API keys — base64 encoded), Ingress (HTTP routing, TLS termination), HorizontalPodAutoscaler (scale based on CPU/custom metrics). PHP-specific: session affinity if not using Redis sessions, shared persistent volumes for uploads (use S3 instead), readiness probes pointing to a health check endpoint.

Common Misconception

Why It Matters

Common Mistakes

• No readiness probe — Kubernetes sends traffic to pods before PHP-FPM is ready.
• No resource requests/limits — a memory-leaking PHP pod can starve other pods on the same node.
• Storing sessions in local PHP session files — pods are ephemeral; use Redis.
• Using latest image tag — non-deterministic; always use immutable image tags (commit SHA).

Code Examples

# Minimal deployment — missing critical settings:
apiVersion: apps/v1
kind: Deployment
spec:
  template:
    spec:
      containers:
      - name: php
        image: myapp:latest  # Non-deterministic tag
        # No resource limits — can OOM other pods
        # No readiness probe — traffic before ready
        # No liveness probe — dead pods receive traffic

# Production-ready PHP deployment:
apiVersion: apps/v1
kind: Deployment
spec:
  template:
    spec:
      containers:
      - name: php
        image: myapp:a3f2c1d  # Immutable SHA tag
        resources:
          requests: {memory: 256Mi, cpu: 100m}
          limits:   {memory: 512Mi, cpu: 500m}
        readinessProbe:
          httpGet: {path: /health, port: 80}
          initialDelaySeconds: 5
        livenessProbe:
          httpGet: {path: /health, port: 80}
          periodSeconds: 10
        envFrom:
        - secretRef: {name: app-secrets}
        - configMapRef: {name: app-config}

References

• ↗ https://kubernetes.io/docs/concepts/workloads/controllers/deployment/

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