Kubectl Command Guide - Part 1

Table of Contents

1. Basic Operations
2. Pod Management
3. Deployment Management
4. Service Management
5. Configuration Management
6. Resource Management
7. Cluster Operations
8. Advanced Operations
9. Troubleshooting
10. Best Practices

Basic Operations

Context and Configuration

# View and manage contexts
kubectl config view
kubectl config get-contexts
kubectl config use-context CONTEXT_NAME
kubectl config set-context --current --namespace=NAMESPACE
 
# Create context with specific credentials
kubectl config set-credentials USER_NAME \
    --client-certificate=path/to/cert.crt \
    --client-key=path/to/key.key
 
# Set cluster details
kubectl config set-cluster CLUSTER_NAME \
    --server=https://kubernetes.example.com \
    --certificate-authority=path/to/ca.crt \
    --embed-certs=true
 
# Create context
kubectl config set-context CONTEXT_NAME \
    --cluster=CLUSTER_NAME \
    --user=USER_NAME \
    --namespace=NAMESPACE

Basic Resource Operations

# Get resources
kubectl get pods,deployments,services -n NAMESPACE
kubectl get all -A
kubectl get pods -o wide
kubectl get pods -o json
kubectl get pods -o yaml
 
# Describe resources
kubectl describe pod POD_NAME
kubectl describe node NODE_NAME
kubectl describe deployment DEPLOYMENT_NAME
 
# Create resources
kubectl create -f manifest.yaml
kubectl apply -f manifest.yaml
kubectl apply -f directory/ -R
 
# Delete resources
kubectl delete -f manifest.yaml
kubectl delete pod POD_NAME --grace-period=0 --force
kubectl delete namespace NAMESPACE --timeout=5m

Pod Management

Pod Operations

# Create pod
kubectl run nginx --image=nginx:latest --port=80
 
# Create pod with advanced options
kubectl run custom-pod \
    --image=nginx:latest \
    --port=80 \
    --labels="app=web,env=prod" \
    --requests="cpu=100m,memory=256Mi" \
    --limits="cpu=200m,memory=512Mi" \
    --env="KEY1=VALUE1,KEY2=VALUE2" \
    --command -- /bin/sh -c "while true; do echo hello; sleep 10; done"
 
# Get pod details
kubectl get pod POD_NAME -o yaml
kubectl get pods --show-labels
kubectl get pods -l app=nginx
kubectl get pods --field-selector status.phase=Running
 
# Pod logs
kubectl logs POD_NAME
kubectl logs POD_NAME -c CONTAINER_NAME
kubectl logs -f POD_NAME
kubectl logs POD_NAME --tail=100
kubectl logs -l app=nginx --all-containers=true
 
# Execute commands in pod
kubectl exec -it POD_NAME -- /bin/bash
kubectl exec POD_NAME -c CONTAINER_NAME -- command
kubectl exec POD_NAME -- env

Advanced Pod Configuration

# Create pod with volume
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: volume-pod
spec:
  containers:
  - name: nginx
    image: nginx
    volumeMounts:
    - name: data
      mountPath: /data
  volumes:
  - name: data
    persistentVolumeClaim:
      claimName: pvc-name
EOF
 
# Create pod with init container
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: init-pod
spec:
  initContainers:
  - name: init
    image: busybox
    command: ['sh', '-c', 'until nslookup service; do echo waiting; sleep 2; done;']
  containers:
  - name: app
    image: nginx
EOF
 
# Create pod with security context
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: secure-pod
spec:
  securityContext:
    runAsUser: 1000
    runAsGroup: 3000
    fsGroup: 2000
  containers:
  - name: nginx
    image: nginx
    securityContext:
      allowPrivilegeEscalation: false
      capabilities:
        drop:
        - ALL
EOF

Deployment Management

Deployment Operations

# Create deployment
kubectl create deployment nginx --image=nginx:latest --replicas=3
 
# Create deployment with advanced options
kubectl create deployment web-app \
    --image=nginx:latest \
    --replicas=3 \
    --port=80 \
    --dry-run=client -o yaml > deployment.yaml
 
# Scale deployment
kubectl scale deployment DEPLOYMENT_NAME --replicas=5
kubectl scale deployment DEPLOYMENT_NAME --replicas=5 --current-replicas=3
 
# Update deployment
kubectl set image deployment/DEPLOYMENT_NAME CONTAINER=IMAGE:TAG
kubectl rollout status deployment/DEPLOYMENT_NAME
kubectl rollout history deployment/DEPLOYMENT_NAME
 
# Rollback deployment
kubectl rollout undo deployment/DEPLOYMENT_NAME
kubectl rollout undo deployment/DEPLOYMENT_NAME --to-revision=2

Advanced Deployment Configuration

# Deployment with rolling update strategy
cat <<EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
spec:
  replicas: 3
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        resources:
          requests:
            cpu: 100m
            memory: 256Mi
          limits:
            cpu: 200m
            memory: 512Mi
        readinessProbe:
          httpGet:
            path: /
            port: 80
          initialDelaySeconds: 5
          periodSeconds: 5
        livenessProbe:
          httpGet:
            path: /
            port: 80
          initialDelaySeconds: 15
          periodSeconds: 15
EOF
 
# Deployment with HPA
kubectl autoscale deployment DEPLOYMENT_NAME \
    --min=3 \
    --max=10 \
    --cpu-percent=80
 
# Create deployment with custom scheduler
cat <<EOF | kubectl apply -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  name: custom-scheduler-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: custom-app
  template:
    metadata:
      labels:
        app: custom-app
    spec:
      schedulerName: custom-scheduler
      containers:
      - name: nginx
        image: nginx:latest
EOF