kubectl ist das Command-Line Tool zur Interaktion mit Kubernetes-Clustern.

Kommuniziert mit dem API Server um Ressourcen zu erstellen, anzeigen, aktualisieren und löschen.

Grundlegende Befehle

# Cluster-Info
kubectl cluster-info
kubectl version

# Nodes anzeigen
kubectl get nodes

# Pods anzeigen
kubectl get pods
kubectl get pods -A           # Alle Namespaces
kubectl get pods -o wide      # Mit mehr Details

# Deployments
kubectl get deployments

# Services
kubectl get services

# Alles anzeigen
kubectl get all
kubectl get all -A

Ressourcen erstellen

# Aus YAML
kubectl apply -f deployment.yaml
kubectl apply -f https://example.com/app.yaml

# Imperativ
kubectl create deployment nginx --image=nginx
kubectl run nginx --image=nginx

# Dry Run (YAML generieren)
kubectl create deployment nginx --image=nginx --dry-run=client -o yaml > deployment.yaml

Ressourcen anzeigen

# Details
kubectl describe pod nginx
kubectl describe deployment nginx

# Logs
kubectl logs nginx-pod
kubectl logs -f nginx-pod           # Follow
kubectl logs --tail=100 nginx-pod

# Events
kubectl get events
kubectl get events --sort-by='.metadata.creationTimestamp'

# Resource Usage
kubectl top nodes
kubectl top pods

Ressourcen bearbeiten

# Interaktiv bearbeiten
kubectl edit deployment nginx

# Skalieren
kubectl scale deployment nginx --replicas=5

# Image aktualisieren
kubectl set image deployment nginx nginx=nginx:1.22

# Rollout
kubectl rollout status deployment nginx
kubectl rollout history deployment nginx
kubectl rollout undo deployment nginx

Ressourcen löschen

# Einzelne Ressource
kubectl delete pod nginx
kubectl delete deployment nginx

# Aus YAML
kubectl delete -f deployment.yaml

# Nach Label
kubectl delete pods -l app=nginx

# Alle Ressourcen
kubectl delete all --all

Exec & Port-Forward

# In Pod einloggen
kubectl exec -it nginx-pod -- /bin/bash
kubectl exec nginx-pod -- ls /var/log

# Port-Forwarding
kubectl port-forward pod/nginx 8080:80
kubectl port-forward service/nginx 8080:80

# Copy Files
kubectl cp local-file.txt nginx-pod:/tmp/
kubectl cp nginx-pod:/var/log/app.log ./app.log

Namespaces

# In Namespace arbeiten
kubectl get pods -n production
kubectl apply -f app.yaml -n production

# Default-Namespace setzen
kubectl config set-context --current --namespace=production

# Namespace erstellen
kubectl create namespace dev

Context & Config

# Contexts anzeigen
kubectl config get-contexts

# Context wechseln
kubectl config use-context minikube
kubectl config use-context production

# Aktueller Context
kubectl config current-context

# Kubeconfig anzeigen
kubectl config view

Output Formats

# Wide
kubectl get pods -o wide

# YAML
kubectl get pod nginx -o yaml

# JSON
kubectl get pod nginx -o json

# JSONPath
kubectl get pods -o jsonpath='{.items[*].metadata.name}'
kubectl get pods -o jsonpath='{.items[*].status.podIP}'

# Custom Columns
kubectl get pods -o custom-columns=NAME:.metadata.name,IP:.status.podIP

Labels & Selectors

# Nach Labels filtern
kubectl get pods -l app=nginx
kubectl get pods -l app=nginx,tier=frontend

# Labels hinzufügen
kubectl label pod nginx env=production

# Labels entfernen
kubectl label pod nginx env-

kubectl Shortcuts

# Ressourcen-Abkürzungen
kubectl get po       # pods
kubectl get deploy   # deployments
kubectl get svc      # services
kubectl get ns       # namespaces
kubectl get no       # nodes
kubectl get cm       # configmaps

# Explain (Dokumentation)
kubectl explain pod
kubectl explain deployment.spec

Zusammenfassung

# Pods
kubectl get pods
kubectl logs pod-name
kubectl exec -it pod-name -- sh

# Deployments
kubectl create deployment app --image=app:v1
kubectl scale deployment app --replicas=3

# Services
kubectl expose deployment app --port=80

Verwandte Konzepte

• Kubernetes - Hauptnotiz
• Kubernetes Helm - Package Manager