kubectl related script

0_kubectl related script

kubectl related script

1 kubectl

#create resource
kubectl create -f <yaml/json file>

# get info
kubectl get nodes

kubectl get pods -n namespace
kubectl get pods --all-namespaces

kubectl get ingress

kubectl config view

kubectl get namespaces

#you can always show more info by using -o wide

#get more information
kubectl describe <type> ... more opt

# cluster performance
kubectl top nodes
kubectl top pods


#remove stuck pods
kubectl get pods --all-namespaces | grep Terminating
kubectl -n namespacename delete pod podname --grace-period 0 --force

#check cluster name
kubectl config current-context


#get all node info
kubectl get node nodename -o yaml

#get pod on single node
kubectl get pods --all-namespaces --field-selector spec.nodeName=<node> -o wide
#get pod with nodename
kubectl get pods --all-namespaces --field-selector spec.nodeName!=null -o wide

#find pod info from uid
kubectl get pod --all-namespaces -o json | jq '.items[] | select(.metadata.uid == "<pod-uid>")'

#find docker id with overlay id
docker ps -a -q | xargs docker inspect | jq '.[] | select(.GraphDriver.Data.LowerDir | contains("overlayid")) | .Id'

#display only name
kubectl get pv -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}'


# delete all evicted pods from all namespaces
kubectl get pods --all-namespaces | grep Evicted | awk '{print $2 " --namespace=" $1}' | xargs kubectl delete pod

# delete all containers in ImagePullBackOff state from all namespaces
kubectl get pods --all-namespaces | grep 'ImagePullBackOff' | awk '{print $2 " --namespace=" $1}' | xargs kubectl delete pod

# delete all containers in ImagePullBackOff or ErrImagePull or Evicted state from all namespaces
kubectl get pods --all-namespaces | grep -E 'ImagePullBackOff|ErrImagePull|Evicted' | awk '{print $2 " --namespace=" $1}' | xargs kubectl delete pod

# delete all container which suck on terminating
kubectl get pods --all-namespaces | grep -E 'Terminating' | awk '{print $2 " --namespace=" $1}' | xargs kubectl delete pod --grace-period 0 --force

# restart all pod
kubectl get deployment -n <namespace> | awk '{print $1}' | xargs kubectl -n <namespace> rollout restart deployment

#set all pod to zero
kubectl get deployment -n <namespace> | awk '{print $1}' | kubectl scale --replicas=0 deployment/


#disable daemonsets
kubectl -n <namespace> patch daemonset <name-of-daemon-set> -p '{"spec": {"template": {"spec": {"nodeSelector": {"non-existing": "true"}}}}}'
#enable
kubectl -n <namespace> patch daemonset <name-of-daemon-set> --type json -p='[{"op": "remove", "path": "/spec/template/spec/nodeSelector/non-existing"}]'

#deployment get info
#image
kubectl get deployment -n "$NAMESPACE" --selector=release="$CHART_NAME"  -o jsonpath="{.items[0].spec.template.spec.containers[0].image}"
kubectl get deployment -n $namespace --field-selector metadata.name="$deployment_name" -o json

#get pod info
kubectl get pods -n "$NAMESPACE" --selector=release="$CHART_NAME"  --field-selector status.phase=Running -o jsonpath="{.items[*].spec.containers[*].image}"

# restart all deployment within namespace
kubectl rollout restart deployment -n <namespace>


#check k8s service status (componentstatus)
kubectl get --raw='/readyz?verbose'
kubectl get cs

# accessing pod
kubectl exec -it <pod> -n <namespace> -- /bin/sh
kubectl exec -it deployment/<deploymentname> -n <namespace> -- /bin/sh

2 kubectl_remove_evicted_pods

#need install jq first

kubectl get po -a --all-namespaces -o json | \
jq  '.items[] | select(.status.reason!=null) | select(.status.reason | contains("Evicted")) | 
"kubectl delete po \(.metadata.name) -n \(.metadata.namespace)"' | xargs -n 1 bash -c

# one line
kubectl get pod --all-namespaces -o json | jq  '.items[] | select(.status.reason!=null) | select(.status.reason | contains("Evicted")) | "kubectl delete po \(.metadata.name) -n \(.metadata.namespace)"' | xargs -n 1 bash

3 usingFlannelinK8s

do it in docker nodes:

echo "ExecStartPost=/sbin/iptables -P FORWARD ACCEPT" >> /etc/systemd/system/docker.service.d/exec_start.conf
systemctl daemon-reload
systemctl restart docker

4 export all yaml

i=$((0))
for n in $(kubectl get -o=custom-columns=NAMESPACE:.metadata.namespace,KIND:.kind,NAME:.metadata.name pv,pvc,configmap,ingress,service,secret,deployment,statefulset,hpa,job,cronjob --all-namespaces | grep -v 'secrets/default-token')
do
	if (( $i < 1 )); then
		namespace=$n
		i=$(($i+1))
		if [[ "$namespace" == "PersistentVolume" ]]; then
			kind=$n
			i=$(($i+1))
		fi
	elif (( $i < 2 )); then
		kind=$n
		i=$(($i+1))
	elif (( $i < 3 )); then
		name=$n
		i=$((0))
		echo "saving ${namespace} ${kind} ${name}"
		if [[ "$namespace" != "NAMESPACE" ]]; then
			mkdir -p $namespace
			kubectl get $kind -o=yaml --export $name -n $namespace > $namespace/$kind.$name.yaml
		fi
	fi
done

5 get all pod resources limit and requests

#!/bin/bash
i=$((0))
outstring=""
for n in $(kubectl get pods --all-namespaces -o go-template --template '{{range .items}}{{.metadata.namespace}} {{.metadata.name}}{{"\n"}}{{end}}')
do
        if (( $i < 1 )); then
            namespace=$n
            i=$(($i+1))

        elif (( $i < 2 )); then


            i=$((0))
            name=$n
            tempjson=$(kubectl get pods -o json $name -n $namespace | jq '.')
            count=$(echo "$tempjson"| jq '.spec.containers | length')
            for ((j = 0; j < $count; j++)); do
                extra=""
                resource=$(echo "$tempjson" | jq ".spec.containers[$j].resources")
                resource_limits_cpu=$(echo "$resource" | jq '.limits.cpu')
                resource_limits_memory=$(echo "$resource" | jq '.limits.memory')
                resource_requests_cpu=$(echo "$resource" | jq '.requests.cpu')
                resource_requests_memory=$(echo "$resource" | jq '.requests.memory')
                if (( $count > 1 )); then
                    extra="(sidercar$j)"
                fi
                #echo -e "$name$extra $namespace $resource_limits_cpu $resource_limits_memory $resource_requests_cpu $resource_requests_memory"
                printf "%s\t%s\t%s\t%s\t%s\t%s\n" $name$extra $namespace $resource_limits_cpu $resource_limits_memory $resource_requests_cpu $resource_requests_memory

            done



        fi
done