Kubernetes Commands: Kubectl Autocomplete, Cluster Nodes, Namespaces, LimitRange Resource Limits, Pods, Deployments, Replication Controllers, Services, HPA, Secrets, Cronjobs, Helm, Logs, K9s TUI

# Install Kubectl
curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl &&
chmod +x kubectl &&
sudo mv kubectl /usr/local/bin/

# List kubectl commands
kubectl -h

# List help for specific command: "get" command
kubectl get -h

# Search installed packages on Deb based system
dpkg -l | grep bash-completion

# Shell output:
ii  bash-completion                      1:2.11-8                                all          programmable completion for the bash shell

# Install bash-completion package
sudo apt update &&
sudo apt install bash-completion -y

# Enable kubectl autocomplete: Current shell
source <(kubectl completion bash)

# Append the command to the .bashrc file
echo "source <(kubectl completion bash)" >> ~/.bashrc

# Apply changes
source ~/.bashrc

# List nodes
kubectl get nodes

# List nodes: More details
kubectl get nodes -o wide

# Shell output: Example
NAME    STATUS   ROLES           AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                         KERNEL-VERSION   CONTAINER-RUNTIME
node1   Ready    control-plane   27h   v1.29.5   192.168.30.71   <none>        Debian GNU/Linux 12 (bookworm)   6.1.0-21-amd64   containerd://1.7.16
node2   Ready    control-plane   27h   v1.29.5   192.168.30.72   <none>        Debian GNU/Linux 12 (bookworm)   6.1.0-21-amd64   containerd://1.7.16
node3   Ready    worker          27h   v1.29.5   192.168.30.73   <none>        Debian GNU/Linux 12 (bookworm)   6.1.0-21-amd64   containerd://1.7.16
node4   Ready    worker          27h   v1.29.5   192.168.30.74   <none>        Debian GNU/Linux 12 (bookworm)   6.1.0-21-amd64   containerd://1.7.16

# Label a worker node
kubectl label nodes <node-name> kubernetes.io/role=worker

# List Kubelet logs of a Kubernetes Node: Run on desired node
sudo journalctl -u kubelet

# List Kubernetes version: Client (Kubectl) & Server (Kubernetes Cluster)
kubectl version

# drain each node, which safely evicts all pods from the node in preparation for maintenance
kubectl drain node3 --ignore-daemonsets --delete-emptydir-data

# Verify the status
kubectl get nodes

# Shell output
NAME    STATUS                     ROLES           AGE    VERSION
node1   Ready                      control-plane   6d1h   v1.29.5
node2   Ready                      control-plane   6d1h   v1.29.5
node3   Ready,SchedulingDisabled   <none>          6d1h   v1.29.5
node4   Ready,SchedulingDisabled   <none>          6d1h   v1.29.5

# Uncord node / mark it as schedulable
kubectl uncordon node3

# Verify the status
kubectl get nodes

# Shell output
NAME    STATUS   ROLES           AGE    VERSION
node1   Ready    control-plane   6d1h   v1.29.5
node2   Ready    control-plane   6d1h   v1.29.5
node3   Ready    <none>          6d1h   v1.29.5
node4   Ready    <none>          6d1h   v1.29.5

# List all namespaces
kubectl get namespaces

# List all namespaces: Short version
kubectl get ns

# Create a new namespace
kubectl create namespace namespace-name

# Create a namespace configuration
vi new-namespace.yaml

apiVersion: v1
kind: Namespace
metadata:
  name: new-namespace

# Deploy the namespace
kubectl create -f new-namespace.yaml

# List namespace details
kubectl describe namespace new-namespace

# Delete the namespace "new-namespace"
kubectl delete namespace new-namespace

# Create pod: In specific namespace
kubectl run pod-name --image=image-name --namespace namespace-name

# Deploy a resource in a specific namespace
kubectl create -f filename.yaml --namespace namespace-name

# List pods: In specific namespace
kubectl get pods --namespace namespace-name

# List deployments: In specific namespace
kubectl get deployments --namespace namespace-name

# List services: In specific namespace
kubectl get services --namespace namespace-name

# List all resources: In specific namespace
kubectl get all -n namespace-name

# For example list pods in all namespaces
kubectl get pods -A

# Delete pod: In specific namespace
kubectl delete pod pod-name --namespace new-namespace

# Delete deployment: In specific namespace
kubectl delete deployment deployment-name --namespace namespace-name

# Delete serice: In specific namespace
kubectl delete service service-name --namespace namespace-name

# List the current kubectl context: Cluster & user
kubectl config view | grep current-context

# Shell output:
current-context: kubernetes-admin@k8s.jkw.local

# Set the namespace "new-namespace" as the default namespace
kubectl config set-context kubernetes-admin@k8s.jkw.local --namespace new-namespace

# Set the namespace "default" as the default namespace
kubectl config set-context kubernetes-admin@k8s.jkw.local --namespace default

# Verify the configuration
kubectl config view

# Shell output:
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: DATA+OMITTED
    server: https://127.0.0.1:6443
  name: k8s.jkw.local
contexts:
- context:
    cluster: k8s.jkw.local
    namespace: new-namespace # Default namespace
    user: kubernetes-admin
  name: kubernetes-admin@k8s.jkw.local
current-context: kubernetes-admin@k8s.jkw.local
kind: Config
preferences: {}
users:
- name: kubernetes-admin
  user:
    client-certificate-data: DATA+OMITTED
    client-key-data: DATA+OMITTED

# Create a LimitRange configuration
vi namespace-limits.yaml

apiVersion: v1
kind: LimitRange
metadata:
  name: example-namespace-limits
  namespace: example-namespace
spec:
  limits:
  - type: Pod
    max:
      cpu: "2"
      memory: "1Gi"
    min:
      cpu: "200m"
      memory: "100Mi"
  - type: Container
    default:
      memory: "300Mi"
      cpu: "200m"
    defaultRequest:
      memory: "200Mi"
      cpu: "100m"
    max:
      memory: "600Mi"
      cpu: "400m"
    min:
      memory: "100Mi"
      cpu: "100m"

# Deploy the LimitRange resource
kubectl create -f namespace-limits.yaml

# List the LimitRange resource for the namespace
kubectl get LimitRange --namespace example-namespace

# Shell output:
NAME                       CREATED AT
example-namespace-limits   2024-06-01T11:33:15Z

# List the namespace details
kubectl describe namespace example-namespace

# Shell output:
Name:         example-namespace
Labels:       kubernetes.io/metadata.name=example-namespace
Annotations:  <none>
Status:       Active

No resource quota.

Resource Limits
 Type       Resource  Min    Max    Default Request  Default Limit  Max Limit/Request Ratio
 ----       --------  ---    ---    ---------------  -------------  -----------------------
 Pod        cpu       200m   2      -                -              -
 Pod        memory    100Mi  1Gi    -                -              -
 Container  memory    100Mi  600Mi  200Mi            300Mi          -
 Container  cpu       100m   400m   100m             200m           -

# Delete the LimitRange resource
kubectl delete LimitRange example-namespace-limits --namespace example-namespace

# Deploy resources from YAML configuration: Current namespace
kubectl create -f filename.yaml

# Deploy resources from YAML configuration: Specific namespace
kubectl create -f filename.yaml -n namespace-name

# Deploy resources updates from YAML configuration: Current namespace
kubectl apply -f filename.yaml

# Deploy resources updates from YAML configuration: Specific namespace
kubectl apply -f filename.yaml -n namespace-name

# Delete resources from YAML configuration: Current namespace
kubectl delete -f filename.yaml

# Delete resources from YAML configuration: Specific namespace
kubectl delete -f filename.yaml

# Save YAML Manifest from existing deployment: Current namespace
kubectl get deployment-type deployment-name -o yaml > filename.yaml

# Save YAML Manifest from existing deployment: Specific namespace
kubectl get deployment-type deployment-name -n namespace-name -o yaml > filename.yaml

# Create a backup of a Deployment
kubectl get deployment coredns -n kube-system -o yaml > coredns-deployment.yaml

# Delete the Deployment
kubectl delete deployment coredns -n kube-system

# Restore the Deployment
kubectl apply -f coredns-deployment.yaml

# List pods
kubectl get pod

# List pods: More details like node name
kubectl get pods -o wide

# # List pods: Watch the status change
kubectl get pods --watch

# List pods: With specific label "nginx"
kubectl get pod -l app=nginx

# List pods: In specific namespace
kubectl get pods --namespace=namespace-name

# List pods: In all namespaces
kubectl get pods --all-namespaces

# List pod details
kubectl describe pod <pod-name>

# Delete pod
kubectl delete pod <pod-name>

# Access an container shell: Single container pod
kubectl exec -it pod-name -- /bin/bash

# Access an container shell: Multi container pod
kubectl exec -it pod-name -c container-name -- /bin/bash

# List environment variables: Single container pod
kubectl exec pod-name -- printenv

# List environment variables: Multi container pod
kubectl exec pod-name -c container-name -- printenv

# Container logs: Single container pod
kubectl logs my-pod

# Container logs: Multi container pod
kubectl logs pod-name -c container-name

# Forward container port: Local access
kubectl port-forward pod-name 8080:80

# Forward container port: Local access, specific namespace
kubectl port-forward pod-name -n namespace-name 8080:80

# Forward container port: Access from other hosts
kubectl port-forward --address 0.0.0.0 pod-name 8080:80

# Forward container port: Access from other hosts, specific namespace
kubectl port-forward --address 0.0.0.0 pod-name -n namespace-name 8080:80

# Curl the local port
curl localhost:8080

# Stop port forwarding
Strg + C

# List deployments
kubectl get deployments

# List deployment details
kubectl describe deployment <deployment-name>

# Set the number of replicas for a deployment 
kubectl scale deployment <deployment-name> --replicas=2

# Delete deployment
kubectl delete deployment <deployment-name>

# List Replication Controllers
kubectl get rc
kubectl describe rc controller-name

# List Replication Controller details
kubectl describe rc controller-name

# Edit Replcation Controller
kubectl edit rc/controller-name

# Delete the replication controller and it's pods
kubectl delete rc controller-name

NAME          TYPE        CLUSTER-IP     EXTERNAL-IP      PORT(S)          AGE
testservice   NodePort    10.233.13.17   192.168.30.100   8000:32007/TCP   2s

# Create service type "ClusterIP" for a deployment
kubectl expose deployment <deployment-name> --port=8000 --target-port=80 --name=<service-name>

# Create service type "ClusterIP" for a deployment: Add external IP to access the service
kubectl expose deployment <deployment-name> --port=8000 --target-port=80 --name=<service-name> --external-ip="192.168.30.100"

# Create service type "NodePort" for a deployment
kubectl expose deployment <deployment-name> --type=NodePort --port=8000 --target-port=80 --name=<service-name>

# Create service type "NodePort" for a deployment: Add external IP to access the service
kubectl expose deployment <deployment-name> --type=NodePort --port=8000 --target-port=80 --name=<service-name> --external-ip="192.168.30.100"

# Create service type "LoadBalancer" for a deployment: Random LoadBalancer IP
kubectl expose deployment <deployment-name> --type=LoadBalancer --port=8000 --target-port=80 --name=<service-name>

# Create service type "LoadBalancer" for a deployment: Define a specific LoadBalancer IP
kubectl expose deployment <deployment-name> --type=LoadBalancer --port=8000 --target-port=80 --name=<service-name> --external-ip="192.168.30.111"

# Create service type "ClusterIP" for a pod
kubectl expose pod <pod-name> --port=8000 --target-port=80 --name=<service-name>

# Create service type "ClusterIP" for a pod: Add external IP to access the service
kubectl expose pod <pod-name> --port=8000 --target-port=80 --name=<service-name> --external-ip="192.168.30.100"

# Create service type "ClusterIP" for a Replication Controller
kubectl expose rc <rc-name> --port=8000 --target-port=80 --name=<service-name>

# Create service type "ClusterIP" for a Replication Controller: Add external IP to access the service
kubectl expose rc <rc-name> --port=8000 --target-port=80 --name=<service-name> --external-ip="192.168.30.100"

# List all services / service details
kubectl get svc

# List service details
kubectl get svc <service-name>

# List more service details
kubectl describe svc <service-name>

# Delete service
kubectl delete service <service-name>

# List storage clases
kubectl get storageclasses

# Delete storage class
kubectl delete storageclass storageclass-name

# List PVC
kubectl get pvc

# Delete PVC
kubectl delete pvc pvc-name

# List PV
kubectl get pv

# Delete PV

kubectl delete pv pv-name

# Deploy a pod autoscaler: Maintains between 1 and 10 pod replicas
kubectl autoscale deployment deployment-name --cpu-percent=50 --min=1 --max=10 --name=hpa-name

# List the HPA status: Wait till the HPA gets a target output from the metrics server
kubectl get hpa

# Wacht the load of the HPA
kubectl get hpa hpa-name --watch

# List HPA details
kubectl describe hpa hpa-name

# Wacht the HPA
kubectl delete hpa hpa-name

# List ConfigMaps: In current namespace
kubectl get cm

# List ConfigMaps: In all namespace
kubectl get cm --all-namespaces

# List ConfigMaps: In specific namespace
kubectl get cm -n namespacename

# Edit ConfigMap: Corrent namespace
kubectl edit cm configmap-name

# Edit ConfigMap: Specific namespace
kubectl edit cm configmap-name -n namespace-name

# List ConfigMap details: Corrent namespace
kubectl describe cm configmap-name

# List ConfigMap details: Specific namespace
kubectl describe cm configmap-name -n namespace-name

# Delete ConfigMap: Corrent namespace
kubectl delete cm configmap-name

# Delete ConfigMap: Specific namespace
kubectl delete cm configmap-name -n namespace-name

# List secrets
kubectl get secrets

# List secret details
kubectl describe secret secret-name

# Delete secret
kubectl delete secret secret-name

# List network policy: Describe all NetworkPolicies in "default" namespace
kubectl describe networkpolicy 

# List network policy: Describe specific "network-policy-ex-pods" np in "default" namespace
kubectl describe networkpolicy networkpolicy-name -n default

# Delete network policy
kubectl delete networkpolicy networkpolicy-name

# Create cronjob configuration
vi example-conjob.yaml

apiVersion: batch/v1
kind: CronJob
metadata:
  name: example-cronjob
spec:
  schedule: "*/1 * * * *"
  jobTemplate: # Defines the job to be created on each schedule occurrence
    spec:
      template: # The Pod template
        spec:
          containers:
          - name: cronjob-container
            image: busybox
            args:
            - /bin/sh
            - -c
            - date; echo Hello from the Kubernetes cluster
          restartPolicy: OnFailure

# Deploy cronjob
kubectl apply -f example-conjob.yaml

# List cronjobs
kubectl get cronjobs

# Shell output:
NAME               SCHEDULE      SUSPEND   ACTIVE   LAST SCHEDULE   AGE
example-cronjob    */1 * * * *   False     0        16s             40s

# List cronjobs: In current namespace
kubectl get cronjobs

# List cronjobs: In a specific namespace
kubectl get cronjobs -n namespace-name

# List cronjobs: In all namespaces
kubectl get cronjobs --all-namespaces

# Suspend cronjob: Example
kubectl patch cronjob example-cronjob -p '{"spec":{"suspend": true}}'

# Verify the cronjob status
kubectl get cronjobs

# Shell output:
NAME               SCHEDULE      SUSPEND   ACTIVE   LAST SCHEDULE   AGE
example-cronjob    */1 * * * *   True      0        43s             67s

# Resume cronjob: Example
kubectl patch cronjob example-cronjob -p '{"spec":{"suspend": false}}'

# Suspend cronjob: Syntax
kubectl patch cronjob cronjob-name -p '{"spec":{"suspend": true}}'

# Resume cronjob: Syntax
kubectl patch cronjob cronjob-name -p '{"spec":{"suspend": false}}'

# List jobs
kubectl get jobs

# Shell output:
NAME                        COMPLETIONS   DURATION   AGE
example-cronjob-28621260   1/1           5s         4m56s
example-cronjob-28621264   1/1           5s         49s

# List cronjobs: In current namespace
kubectl describe cronjob cronjob-name

# List cronjobs: In a specific namespace
kubectl describe cronjob cronjob-name -n namespace-name

# Delete cronjob: In current namespace
kubectl delete cronjob cronjob-name 

# Delete cronjob: In a specific namespace
kubectl delete cronjob cronjob-name -n namespace-name

# Install Helm with script
curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 &&
chmod +x get_helm.sh &&
./get_helm.sh

# Verify the installation / check version
helm version

# Add repository
helm repo add repo-alias https://repo-url

# Update package index
helm repo update

# List repositories
helm repo list

# Remove repository
helm repo remove repo-alias

# List available charts in the Helm repository
helm search repo repo-alias

# Install package: Syntax
helm install release-name repo-alias/chart-name

# For example
helm install metrics-server metrics-server/metrics-server

# Uninstall package: Current namespace
helm uninstall release-name

# Uninstall package: Specific namespace
helm delete velero -n namespace-name

# List Helm releases in the `namespace-name` namespace
helm ls -n namespace-name

# List Helm releases across all namespaces
helm ls --all-namespaces

# Download & untar a Helm chart
helm pull repo-alias/chart-name --untar

# List the logs of a pod: Single container pod, current namespace
kubectl logs pod-name

# List the logs of a pod: Single container pod, specific namespace
kubectl logs pod-name -n namespace-name

# List the logs of a pod: Multi container pod, current namespace
kubectl logs pod-name -c container-name

# List the logs of a pod: Multi container pod, specific namespace
kubectl logs pod-name -c container-name -n namespace-name

# Logs from the last 5 minutes: Current namespace
kubectl logs pod-name --since=5m

# Logs from the last 5 minutes: Specific namespace
kubectl logs pod-name --since=5m -n namespace-name


# Logs from the last 24 hours: Current namespace
kubectl logs pod-name --since=24h

# Logs from the last 24 hours: Specific namespace
kubectl logs pod-name --since=24h -n namespace-name

# Real-time logs from all containers in a pod: Current namespace
kubectl logs -f --all-containers=true pod-name

# Real-time logs from all containers in a pod: Specific namespace
kubectl logs -f --all-containers=true pod-name -n namespace-name

# Run pod for network troubleshooting 
kubectl run busybox --image=busybox --restart=Never --stdin --tty

# Run commands
nslookup example.com
ping example.com

# Delete pod
kubectl delete pod busybox

# Download package (Debian based)
wget https://github.com/derailed/k9s/releases/download/v0.32.5/k9s_linux_amd64.deb

# Install package
sudo dpkg -i k9s_linux_amd64.deb

# Install missing dependencies
sudo apt install -f

# Verify installation / check version
k9s version

# Start k9s
k9s

# Exit k9s
Strg + C

# List nodes
:node

# List namespaces
:ns

# List deployments
:deploy

# List pods
:pod

# List services
:svc

# Go back
ESC

# List logs
l