utilities/kubectl.md at master · jaichenchlani/utilities

kubectl reference

Books and Github reference

Kubernetes Patterns - Reusable Elements for Designing Cloud-Native Applications Book: https://drive.google.com/drive/u/0/folders/1l4LxrtghKI8IpzVo1If6JuoihrPu3W8K
GitHub Repo: https://github.com/k8spatterns

Imperative Command Examples

  app-secret --from-literal=DB_Host=mysql \
             --from-literal=DB_User=root
             --from-literal=DB_Password=password

kubectl run nginx --image=nginx Create an NGINX pod kubectl run nginx --image=nginx --dry-run=client -o yaml Generate pod manifest yaml file; don't create it kubectl create deployment --image=nginx nginx Create a deployment kubectl create deployment --image=nginx nginx --dry-run -o yaml Generate deployment yaml; don't create it kubectl create deployment nginx --image=nginx --replicas=4 Generate deployment with 4 replicas kubectl expose pod redis --port=6379 --name redis-service --dry-run=client -o yaml Create a Service named redis-service of type ClusterIP to expose pod redis on port 6379 kubectl expose pod nginx --port=80 --name nginx-service --type=NodePort --dry-run=client -o yaml Create a Service named nginx of type NodePort to expose pod nginx's port 80 on port 30080 on the nodes kubectl taint nodes $node key=value:taint-effect taint-effect (NoSchedule|PreferNoSchedule|NoExecute) kubectl taint nodes controlplane node-role.kubernetes.io/master:NoSchedule Untaint node kubectl set image deployment/myapp nginx=nginx:1.9.1 Update deployment to set a different version of nginx kubectl rollout status deployment/myapp Check status of rollout kubectl rollout history deployment/myapp Check status of rollout kubectl rollout undo deployment/myapp Rollback

Google Cloud resources you can create with Config Connector:

kubectl get crds --selector cnrm.cloud.google.com/managed-by-kcc=true

Get the cluster config view.

kubectl config view --raw --flatten > cluster.yaml This gives you all of your config setup on your laptop, across all GCP accounts. The cluster.yaml produced from this command will be used to setup nethopper.

Get the External IPs of all the nodes

kubectl get nodes -o wide --no-headers 2>/dev/null | awk '{print $7}'

Rollout Restart all the apps in a namespace

for app in $(kubectl get deployments -n $ns --no-headers --output=custom-columns="name:.metadata.name"); do kubectl rollout restart deploy/$app -n $ns; done

Get the pods in Running Status

kubectl get pods --all-namespaces --field-selector status.phase=Running

Get the pods in Pending Status

kubectl get pods --all-namespaces --field-selector status.phase=Pending

Get the pods in a namespace

kubectl get pods --all-namespaces --field-selector metadata.namespace=esx-i9-qa

Get the Pending pods in a namespace

kubectl get pods --all-namespaces --field-selector metadata.namespace=<ns>,status.phase=Pending

Get the Pods for a Deployment

kubectl get pods -n <ns> -l app=i9-document-api

Get status reasons for unhealthy containers in a particular namespace

kubectl get pods --all-namespaces --field-selector metadata.namespace=<ns>,status.phase=Pending --output=custom-columns="NAME:.metadata.name,STATUS:.status.phase,CONTAINERS:.status.containerStatuses[].name,STATE:.status.containerStatuses[].state"

Get status reasons for unhealthy containers in a particular DEPLOYMENT

kubectl get pods --all-namespaces --field-selector metadata.namespace=<ns>,status.phase=Pending -l app=i9-converter-service --output=custom-columns="NAME:.metadata.name,STATUS:.status.phase,CONTAINERS:.status.containerStatuses[].name,STATE:.status.containerStatuses[].state"

Get the container status for a particular pod

kubectl get pod i9-converter-service-6c7b47df64-ftxxd -n <ns> --output=custom-columns="NAME:.metadata.name,STATUS:.status.phase,CONTAINERS:.status.containerStatuses[].name,STATE:.status.containerStatuses[].state"

Get total number of pods

kubectl get pods --all-namespaces --no-headers --field-selector metadata.namespace=<ns> --output=custom-columns="NAME:.metadata.name" | wc -l

Create an NGINX Pod

kubectl run nginx --image=nginx

Generate POD Manifest YAML file (-o yaml). Don't create it(--dry-run)

kubectl run nginx --image=nginx --dry-run=client -o yaml

Create a deployment

kubectl create deployment --image=nginx nginx kubectl create deployment web-server --image=gcr.io/engaged-reducer-318105/sre-demo:v1

Expose the deployment via a service

kubectl expose deployment web-server --type LoadBalancer --port 80 --target-port 80

Generate Deployment YAML file (-o yaml). Don't create it(--dry-run)

kubectl create deployment --image=nginx nginx --dry-run=client -o yaml

Generate Deployment YAML file (-o yaml). Don't create it(--dry-run) with 4 Replicas (--replicas=4)

kubectl create deployment --image=nginx nginx --dry-run=client -o yaml > nginx-deployment.yaml

kubectl context management

ns=observability kubectl config set-context $(kubectl config current-context) --namespace=$ns Set a namespace as the default namespace kubectl config set-context --current --namespace sample Just update the default namespace in the current cluster context kubectl config get-contexts Describe one or many contexts kubectl config use-contexts Set the current-context in a kubeconfig file

Expose a Deployment

kubectl expose deployment hello-world --type=NodePort --name=example-service

nginx is just the example; could be any deployment

Create Objects:

kubectl apply -f nginx.yaml (declarative)
kubectl run --image=nginx nginx
kubectl create deployment --image=nginx nginx
kubectl expose deployment nginx --port 80

Update Objects:
kubectl apply -f nginx.yaml (declarative)
kubectl edit deployment nginx
kubectl scale deployment nginx --replicas=5
kubectl set image deployment nginx nginx=nginx:1.18

Imperative: Create a service redis-service exposing a pod

kubectl expose pod redis --port 6379 --type ClusterIP --name redis-service

Taint and Tolerance

kubectl taint nodes $node key=value:taint-effect

taint-effect : NoSchedule | PreferNoSchedule | NoExecute(existing pods will be evicted)

Get the nodes in the default pool

kubectl get nodes -l cloud.google.com/gke-nodepool=default-pool

Drain all the nodes in default pool

for node in $(kubectl get nodes -l cloud.google.com/gke-nodepool=default-pool -o=name); do
  kubectl drain --force --ignore-daemonsets --delete-emptydir-data --grace-period=10 "$node";
done

Istio Injection

kubectl label namespace default istio-injection=enabled

Delete ALL resources in a Namespace

ns=monitoring
kubectl delete all --all -n $ns

Get Containers running in all Pods - All Namespaces

kubectl get pods --all-namespaces -o jsonpath='{range .items[*]}{@.metadata.name}{"\n"}{@.metadata.namespace}{"\n"}{@.spec.nodeName}{"\n"}{@.spec.containers[*].name}{"\n"}{@.spec.containers[*].image}{"\n"}{@.spec.containers[*].resources.requests.cpu}{"\n"}{@.spec.containers[*].resources.requests.memory}{"\n"}{@.spec.containers[*].resources.limits.cpu}{"\n"}{@.spec.containers[*].resources.limits.memory}{"\n"}{end}'

Get Containers running in all Pods - Specified Namespace

kubectl get pods -n $ns -o jsonpath='{range .items[*]}{@.metadata.name}{"\n"}{@.metadata.namespace}{"\n"}{@.spec.nodeName}{"\n"}{@.spec.containers[*].name}{"\n"}{@.spec.containers[*].image}{"\n"}{@.spec.containers[*].resources.requests.cpu}{"\n"}{@.spec.containers[*].resources.requests.memory}{"\n"}{@.spec.containers[*].resources.limits.cpu}{"\n"}{@.spec.containers[*].resources.limits.memory}{"\n"}{end}'

Get Containers running in A Pod - Specified Namespace

kubectl get pods -n $ns --field-selector metadata.name=$pod -o jsonpath='{range .items[*]}{@.metadata.name}{"\n"}{@.metadata.namespace}{"\n"}{@.spec.nodeName}{"\n"}{@.spec.containers[*].name}{"\n"}{@.spec.containers[*].image}{"\n"}{@.spec.containers[*].resources.requests.cpu}{"\n"}{@.spec.containers[*].resources.requests.memory}{"\n"}{@.spec.containers[*].resources.limits.cpu}{"\n"}{@.spec.containers[*].resources.limits.memory}{"\n"}{end}'

Loop through to get the containers...

for i in 0 1; do kubectl get pods -n $ns --no-headers -o=custom-columns=container:.spec.containers[$i].name,pod:.metadata.name,namespace:.metadata.namespace,node:.spec.nodeName,cpu_request:.spec.containers[$i].resources.requests.cpu,memory_request:.spec.containers[$i].resources.requests.memory,cpu_limit:.spec.containers[$i].resources.limits.cpu,memory_limit:.spec.containers[$i].resources.limits.memory; done

Get Deployments Custom Columns

kubectl get deployment --all-namespaces -o=custom-columns=app:.metadata.name,namespace:.metadata.namespace,env:.metadata.labels.environment,version:.metadata.labels.version,replicas:.status.availableReplicas,cpu_request:.spec.template.spec.containers[0].resources.requests.cpu,memory_request:.spec.template.spec.containers[0].resources.requests.memory,cpu_limit:.spec.template.spec.containers[0].resources.limits.cpu,memory_limit:.spec.template.spec.containers[0].resources.limits.memory

Get deployments Custom Columns

kubectl get deployment -n $ns -o=custom-columns=app:.metadata.name,namespace:.metadata.namespace,env:.metadata.labels.environment,version:.metadata.labels.version,replicas:.status.availableReplicas,cpu_request:.spec.template.spec.containers[0].resources.requests.cpu,memory_request:.spec.template.spec.containers[0].resources.requests.memory,cpu_limit:.spec.template.spec.containers[0].resources.limits.cpu,memory_limit:.spec.template.spec.containers[0].resources.limits.memory

Get HPA Custom Columns

kubectl get hpa --all-namespaces -o=custom-columns=app:.metadata.name,namespace:.metadata.namespace,hpa_min_replicas:.spec.minReplicas,hpa_max_replicas:.spec.maxReplicas,hpa_target_cpu_threshold:.spec.targetCPUUtilizationPercentage,hpa_current_cpu_percent:.status.currentCPUUtilizationPercentage,hpa_current_replicas:.status.currentReplicas,hpa_desired_replicas:.status.desiredReplicas,hpa_last_scale_time:.status.lastScaleTime

Get ConfigMap (for Java Options)

kubectl get configmap --all-namespaces -o custom-columns=app:.metadata.name,namespace:.metadata.namespace,java_options:.data._JAVA_OPTIONS

Get Virtual Services

kubectl get vs --all-namespaces --output=custom-columns="NAME:.metadata.name,NAMESPACE:.metadata.namespace,GATEWAYS:.spec.gateways[*],HOSTS:.spec.hosts[*],URI:.spec.http[*].match[*].uri,ROUTE:.spec.http[*].route[*].destination.host"

Get all the apps in a namespace

kubectl get deployment -n $ns -o jsonpath='{.items[*].metadata.labels.app}'

Get the App Version

kubectl get deployment --selector=app=$app -n $n -o jsonpath='{.items[*].metadata.labels.version}' kubectl get deployment -l app=$app -n $n -o jsonpath='{.items[*].metadata.labels.version --output=custom-columns="NAME:.metadata.name,IMAGE:.spec.containers[*].image” kubectl get deployment -l app=$app -n $n --output=custom-columns=“VERSION:.metadata.labels.version”

Get ALL pods for a Deployment

kubectl get pods -n $ns -l app=$app kubectl get pods -n $ns -l app=$app --no-headers | wc -l | tr -d ' '

Get RUNNING Status pods for a Deployment

kubectl get pods -n $ns -l app=$app --field-selector status.phase=Running kubectl get pods -n $ns -l app=$app --field-selector status.phase=Running --no-headers --ignore-not-found=true | wc -l | tr -d ' '

Get PENDING Status pods for a Deployment

kubectl get pods -n $ns -l app=$app --field-selector status.phase=Pending kubectl get pods -n $ns -l app=$app --field-selector status.phase=Pending --no-headers --ignore-not-found=true | wc -l | tr -d ' '

Get ALL pods across ALL Namespaces

kubectl get pods --all-namespaces kubectl get pods --all-namespaces --no-headers --ignore-not-found=true | wc -l | tr -d ' '

Get RUNNING Status pods across ALL Namespaces

kubectl get pods --all-namespaces --field-selector status.phase=Running kubectl get pods --all-namespaces --field-selector status.phase=Running --no-headers --ignore-not-found=true | wc -l | tr -d ' '

Get PENDING Status pods across ALL Namespaces

kubectl get pods --all-namespaces --field-selector status.phase=Pending kubectl get pods --all-namespaces --field-selector status.phase=Pending --no-headers --ignore-not-found=true| wc -l | tr -d ' '

Get SUCCEEDED Status pods across ALL Namespaces

kubectl get pods --all-namespaces --field-selector status.phase=Succeeded kubectl get pods --all-namespaces --field-selector status.phase=Succeeded --no-headers --ignore-not-found=true| wc -l | tr -d ' '

Get FAILED Status pods across ALL Namespaces

kubectl get pods --all-namespaces --field-selector status.phase=Failed kubectl get pods --all-namespaces --field-selector status.phase=Failed --no-headers --ignore-not-found=true| wc -l | tr -d ' '

Get ALL pods for a Namespace

kubectl get pods --all-namespaces --field-selector metadata.namespace=$ns kubectl get pods --all-namespaces --field-selector metadata.namespace=$ns --no-headers --ignore-not-found=true| wc -l | tr -d ' '

Get RUNNING Status pods for a Namespace

kubectl get pods --all-namespaces --field-selector metadata.namespace=$ns,status.phase=Running kubectl get pods --all-namespaces --field-selector metadata.namespace=$ns,status.phase=Running --no-headers --ignore-not-found=true | wc -l | tr -d ' '

Get PENDING Status pods for a Namespace

kubectl get pods --all-namespaces --field-selector metadata.namespace=$ns,status.phase=Pending kubectl get pods --all-namespaces --field-selector metadata.namespace=$ns,status.phase=Pending --no-headers --ignore-not-found=true | wc -l | tr -d ' '

Get FAILED Status pods for a Namespace

kubectl get pods --all-namespaces --field-selector metadata.namespace=$ns,status.phase=Failed kubectl get pods --all-namespaces --field-selector metadata.namespace=$ns,status.phase=Failed --no-headers --ignore-not-found=true | wc -l | tr -d ' '

Get SUCCEEDED Status pods for a Namespace

kubectl get pods --all-namespaces --field-selector metadata.namespace=$ns,status.phase=Succeeded kubectl get pods --all-namespaces --field-selector metadata.namespace=$ns,status.phase=Succeeded --no-headers --ignore-not-found=true | wc -l | tr -d ' '

Get Pod Image

kubectl get pods -o wide -n $ns --output=custom-columns="NAME:.metadata.name,IMAGE:.spec.containers[*].image"

Get Deployment Images

kubectl get deployments --all-namespaces --output=custom-columns="KIND:.kind,NAME:.metadata.name,Namespace:.metadata.namespace,IMAGE:.spec.template.spec.containers[*].image"

Get CronJob Images

kubectl get cronjobs --all-namespaces --output=custom-columns="KIND:.kind,NAME:.metadata.name,Namespace:.metadata.namespace,IMAGE:spec.jobTemplate.spec.template.spec.containers[*].image"

Get status reasons for unhealthy containers in a particular namespace

kubectl get pods --all-namespaces --field-selector metadata.namespace=esx-i9-qa,status.phase=Pending --output=custom-columns="NAME:.metadata.name,STATUS:.status.phase,CONTAINERS:.status.containerStatuses[*].name,STATE:.status.containerStatuses[*].state"

Get status reasons for unhealthy containers in a particular DEPLOYMENT

kubectl get pods --all-namespaces --field-selector metadata.namespace=esx-i9-qa,status.phase=Pending -l app=i9-converter-service --output=custom-columns="NAME:.metadata.name,STATUS:.status.phase,CONTAINERS:.status.containerStatuses[*].name,STATE:.status.containerStatuses[*].state"

Get the container status for a particular pod

kubectl get pod i9-converter-service-6c7b47df64-ftxxd -n esx-i9-qa --output=custom-columns="NAME:.metadata.name,STATUS:.status.phase,CONTAINERS:.status.containerStatuses[*].name,STATE:.status.containerStatuses[*].state"

Get total number of pods

kubectl get pods --all-namespaces --no-headers --field-selector metadata.namespace=esx-i9-prd --output=custom-columns="NAME:.metadata.name" | wc -l kubectl get pod i9-converter-service-6c7b47df64-fxzkg -n esx-i9-qa --output=custom-columns=“NAME:.metadata.name,CONTAINERS:.status.containerStatuses[*].name,STATE:.status.containerStatuses[*].state"

describe pod

kubectl describe pod i9-converter-service-6c7b47df64-fxzkg -n esx-i9-qa | grep Events: -A 10

Get virtual services

Get all the pods that are not 1.9.5

kubectl get pods -o wide --all-namespaces --output=custom-columns="NAME:.metadata.name,SPACE:.metadata.namespace,IMAGE:.spec.containers[*].image" | grep istio | sed /1.9.5/d

Disable PRD West Gateway

kubectl scale deployment --replicas=0 ilb-gateway-api-ext-prd -n istio-system kubectl scale deployment --replicas=0 ilb-gateway-ui-prd -n istio-system

Enable UAT East Gateway

kubectl scale deployment --replicas=1 istio-ilbgateway-esportal-ui-pub-uat -n istio-system

Get HPA

kubectl get hpa -n es-portal-dev

Important Flags:

--all-namespaces
—show-labels

Basic commands

kubectl get ns
kubectl get deployments --namespace es-portal-prd
kubectl get deployments --namespace es-portal-prd | awk '{print $1}' 	
kubectl get services --namespace es-portal-prd
kubectl get pods --namespace es-portal-prd
kubectl get nodes | awk '{print $1}'

Search by Labels:

kubectl get deployments --all-namespaces -l app=audit-api kubectl get deployments --all-namespaces -l 'app in (audit-api,user-api)'

Get the Node Capacity and Allocatable Resources

kubectl describe node $node | grep Allocatable -B 7 -A 6

Get the Node Requests and Limits

kubectl describe node $node | grep 'Allocated resources:' -A 5

Get Max number of pods a node can schedule

kubectl describe node $node | grep pods: | head -1 | awk 'BEGIN { FS = "[ :,}()]+" } { printf "%d", $3 } '

Get Non-terminated pods running on a node

kubectl describe node $node | grep "Non-terminated Pods:" | head -1 | awk 'BEGIN { FS = "[ :,}()]+" } { printf “%d”, $3 } '

Get all the pods running on a Node

kubectl get pods --all-namespaces -o wide --field-selector spec.nodeName=$node | awk 'BEGIN { FS = "[ :,}()]+" }{ printf “%d”, $3 } ' kubectl get pods --all-namespaces -o wide --field-selector spec.nodeName=$node | awk '{print $1,$2,$3,$4,$5,$6,$7,$8,$9}' $1: Namespace $2: Name of the Pod’{} $4: Status $5: Restarts $6: Age $7: IP

Get the node description in a json format

kubectl get node $node -o json

Get the deployment description in a json format

kubectl get deployment $d --namespace $ns -o json

Get Image name for a namespace-deployment combination

temp=$(kubectl describe deployment $d --namespace $ns | grep Image: | awk 'BEGIN { FS = "[ :,}()/@]+" } { printf "%s %s %s %s",$3,$4,$5,substr($8,1,12) } ') project=$(echo $temp | awk '{printf "%s/%s",$1,$2}') repository=$(echo $temp | awk '{print $3}') sha=$(echo $temp | awk '{print $4}')

Get the Deployment version

version=$(kubectl describe deployment $d --namespace $ns | grep version= | head -1 | awk 'BEGIN { FS = "[ :,}()/@]+" } { printf "%s", substr($2,9) } ') kubectl get pods -l 'environment in (production, qa)'

Kubectl jsonpath examples:

kubectl get pods -n es-portal-dev -l app=audit-api -o=jsonpath='{.items[0].spec.containers[0].resources}' kubectl get pods -n es-portal-dev -l app=audit-api -o=jsonpath='{.items[0].status.conditions}' kubectl get pods -n es-portal-dev -l app=audit-api -o=jsonpath='{.items[0].apiVersion}' Kubectl custom-columns example kubectl get pods --all-namespaces --no-headers=true -o=custom-columns=NAME:.metadata.name

Explain command gives you good information about the commands.

kubectl explain pods kubectl explain pods.spec.containers

Run an interactive shell within the pod

kubectl exec monolith --stdin --tty -c monolith /bin/sh

Scale a deployment

kubectl scale deployment hello --replicas=3

Get replicasets

kubectl get replicaset

Kubectl Rolling Update Commands

kubectl rollout history deployment/hello
kubectl rollout pause deployment/hello
kubectl rollout resume deployment/hello
kubectl rollout status deployment/hello
kubectl rollout undo deployment/hello

Log in to a GKE POD

export FORTIO_POD=$(kubectl get pods -l app=fortio -o 'jsonpath={.items[0].metadata.name}') kubectl exec "$FORTIO_POD" -c fortio -- /usr/bin/fortio curl -quiet http://httpbin:8000/get

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kubectl reference

Books and Github reference

Imperative Command Examples

Google Cloud resources you can create with Config Connector:

Get the cluster config view.

Get the External IPs of all the nodes

Rollout Restart all the apps in a namespace

Get the pods in Running Status

Get the pods in Pending Status

Get the pods in a namespace

Get the Pending pods in a namespace

Get the Pods for a Deployment

Get status reasons for unhealthy containers in a particular namespace

Get status reasons for unhealthy containers in a particular DEPLOYMENT

Get the container status for a particular pod

Get total number of pods

Create an NGINX Pod

Generate POD Manifest YAML file (-o yaml). Don't create it(--dry-run)

Create a deployment

Expose the deployment via a service

Generate Deployment YAML file (-o yaml). Don't create it(--dry-run)

Generate Deployment YAML file (-o yaml). Don't create it(--dry-run) with 4 Replicas (--replicas=4)

kubectl context management

Expose a Deployment

nginx is just the example; could be any deployment

Imperative: Create a service redis-service exposing a pod

Taint and Tolerance

Get the nodes in the default pool

Drain all the nodes in default pool

Istio Injection

Delete ALL resources in a Namespace

Get Containers running in all Pods - All Namespaces

Get Containers running in all Pods - Specified Namespace

Get Containers running in A Pod - Specified Namespace

Loop through to get the containers...

Get Deployments Custom Columns

Get deployments Custom Columns

Get HPA Custom Columns

Get ConfigMap (for Java Options)

Get Virtual Services

Get all the apps in a namespace

Get the App Version

Get ALL pods for a Deployment

Get RUNNING Status pods for a Deployment

Get PENDING Status pods for a Deployment

Get ALL pods across ALL Namespaces

Get RUNNING Status pods across ALL Namespaces

Get PENDING Status pods across ALL Namespaces

Get SUCCEEDED Status pods across ALL Namespaces

Get FAILED Status pods across ALL Namespaces

Get ALL pods for a Namespace

Get RUNNING Status pods for a Namespace

Get PENDING Status pods for a Namespace

Get FAILED Status pods for a Namespace

Get SUCCEEDED Status pods for a Namespace

Get Pod Image

Get Deployment Images

Get CronJob Images

Get status reasons for unhealthy containers in a particular namespace

Get status reasons for unhealthy containers in a particular DEPLOYMENT

Get the container status for a particular pod

Get total number of pods

describe pod

Get virtual services

Get all the pods that are not 1.9.5

Disable PRD West Gateway

Enable UAT East Gateway

Get HPA

Important Flags:

Basic commands

Search by Labels:

Get the Node Capacity and Allocatable Resources

Get the Node Requests and Limits

Get Max number of pods a node can schedule