kubernetes-basics

name	kubernetes-basics
description	Kubernetes: Pods, services, deployments, scaling, and orchestration patterns.
triggers	{"extensions":[".yaml"],"keywords":["k8s","kubernetes","pod","deployment","service","ingress","configmap","secret","helm"]}
auto_load_when	Writing Kubernetes manifests or configs
agent	devops-engineer
tools	["Read","Write","Bash"]

Kubernetes Patterns

Focus: Orchestration, scaling, deployment

---

1. When to Use Kubernetes

Use Kubernetes when:

├── Container orchestration needed
    && Multiple containers working together
    && Service discovery
│
├── Scaling requirements
    && Auto-scale based on load
    && Different from simple managed services
│
├── Complex deployment patterns
    && Rolling updates, canary, blue-green
    && Multiple environments
│
└── Team needs autonomy
    && Independent deployments
    && Different services, different teams

Don't use when:

├── Simple workloads
    && Single container, no scaling
    && Managed service enough (RDS, etc)
│
├── Limited K8s expertise
    && High operational burden
    && Learning curve
│
└── Cost sensitive
    && Overhead of orchestration
    && Simpler alternatives work

---

2. Resource Patterns

When to use what:

├── Pod
    && Smallest deployable unit
    && Usually via Deployment, not directly
    && One or more containers
│
├── Deployment
    && Manage Pod replicas
    && Rolling updates
    && Rollback capability
│
├── Service
    && Stable endpoint for Pods
    || Load balancing
    && Types: ClusterIP, NodePort, LoadBalancer
│
├── ConfigMap/Secret
    && Configuration data
    || Sensitive data (secrets)
    && Mounted as files or env vars
│
└── Ingress
    && HTTP routing
    && Host/path-based routing
    && TLS termination

---

3. Scaling Patterns

How to scale:

├── Horizontal Pod Autoscaler (HPA)
    && Scale replicas based on metrics
    && CPU, memory, custom metrics
    && Min/max replicas
│
├── Vertical Pod Autoscaler (VPA)
    && Adjust resource requests
    && Warning: restarts Pods
│
├── Cluster Autoscaler
    && Scale nodes in/out
    && For node-level scaling
│
└── Horizontal scaling preferred
    && More resilient than vertical
    && Better for most workloads

---

4. Deployment Strategies

When to use each:

├── Rolling update (default)
    && Gradually replace old Pods
    && No downtime
    && Easy to monitor
│
├── Blue-green
    && Two identical environments
    && Switch traffic at once
    && Fast rollback
│
├── Canary
    && Small % to new version
    && Monitor, then increase
    && Good for risky changes
│
└── Recreate
    && All at once
    && Downtime but simple
    && For dev/test

---

5. Service Mesh Considerations

When to add service mesh:

├── Need observability
    && Distributed tracing
    && Service-to-service metrics
│
├── Complex traffic management
    && A/B testing
    && Circuit breaking
    && Retries, timeouts
│
└── Security
    && mTLS between services
    && Fine-grained policies

Service mesh options:

├── Istio - full-featured, complex
├── Linkerd - simpler, lighter
├── Consul - also service discovery
└── Not needed when: simple, no traffic complexity

---

Key Patterns

1. Deployments, not naked Pods — Manage with ReplicaSets
2. Services for stable endpoints — Don't expose Pods directly
3. Horizontal scaling first — More resilient than vertical
4. Rolling updates by default — Safe, easy
5. Liveness/readiness probes — Don't skip

---

Anti-Patterns

❌ Running containers as root in pods
✅ securityContext: runAsNonRoot: true; runAsUser: 1000

❌ No resource limits on containers (noisy neighbor)
✅ Always set requests and limits for CPU and memory

❌ kubectl apply -f with no review
✅ GitOps: ArgoCD / Flux sync from git; no manual kubectl in prod

❌ All pods in default namespace
✅ Namespaces per team/environment with RBAC policies

❌ No liveness/readiness probes
✅ Readiness: ready to serve traffic; liveness: restart if stuck

---

Quick Reference

Resource	Purpose	Key fields
Deployment	Manage pod replicas	replicas, selector, template
Service	Network endpoint	ClusterIP, LoadBalancer, NodePort
Ingress	HTTP routing	rules, TLS, annotations
ConfigMap	Non-secret config	data key-value
Secret	Sensitive config	data base64-encoded
HPA	Auto-scale pods	minReplicas, maxReplicas, metrics

🌍 Universal Language Support

• Turkish Native: This skill natively supports Turkish. If the user prompt is in Turkish, all analysis, formatting, and output MUST be entirely in Turkish. You do not need explicit "write in Turkish" instructions.