Kubectl

sudo curl -fsSLo /etc/apt/keyrings/kubernetes-archive-keyring.gpg\
 https://packages.cloud.google.com/apt/doc/apt-key.gpg

cat << EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list >/dev/null
deb [arch=$(dpkg --print-architecture)\
 signed-by=/etc/apt/keyrings/kubernetes-archive-keyring.gpg]\
 https://apt.kubernetes.io/ kubernetes-xenial main
EOF

sudo apt update
sudo apt install kubectl

Kubeconfig

Kubernetes components like kubelet, kube-controller-manager, or kubectl use the kubeconfig file to interact with the Kubernetes API. Usually, the kubectl or oc commands use the kubeconfig file.

The kubeconfig file's default location for kubectl or oc is the ~/.kube directory. Instead of using the full kubeconfig name, the file is just named config. The default location of the kubeconfig file is ~/.kube/config. There are other ways to specify the kubeconfig location, such as the KUBECONFIG environment variable or the kubectl --kubeconfig parameter.

The kubeconfig file is a YAML file containing groups of clusters, users, and contexts.

• A cluster is a Kubernetes or OpenShift cluster.
• A user is a credential used to interact with the Kubernetes API.
• A context is a combination of a cluster and a user. Every time you execute an oc or kubectl command, you reference a context inside kubeconfig.

export KUBECONFIG=$HOME/.kube/chorke-academia-kubeconfig.yaml
chmod 600 $HOME/.kube/chorke-academia-kubeconfig.yaml

Kube Export

for n in $(kubectl get -o=name pvc,configmap,serviceaccount,\
secret,ingress,service,deployment,statefulset,hpa,job,cronjob);do
    mkdir -p $(dirname $n); kubectl get -o=yaml --export $n > $n.yaml
done

for n in $(kubectl get -o=name pvc,configmap,ingress,service,secret,\
deployment,statefulset,hpa,job,cronjob | grep -v 'secret/default-token');do
    kubectl get -o=yaml --export $n > $(dirname $n)_$(basename $n).yaml
done

Switch Knife

kubectl run -i --tty --rm debug --image=busybox --restart=Never -- sh
kubectl run -i --tty --rm debug --image=alpine  --restart=Never -- sh
apk add inetutils-telnet

kubectl config view --minify -o jsonpath='{.clusters[].name}'
kubectl cluster-info
kubectl config view

K8s Lens

# install from snapcraft
sudo snap install kontena-lens --classic

# license version
curl -fsSL https://downloads.k8slens.dev/keys/gpg\
| sudo gpg --dearmor -o /etc/apt/keyrings/k8slens.gpg

cat << EOF | sudo tee /etc/apt/sources.list.d/k8slens.list >/dev/null
deb [arch=$(dpkg --print-architecture)\
 signed-by=/etc/apt/keyrings/k8slens.gpg]\
 https://downloads.k8slens.dev/apt/debian stable main
EOF

sudo apt install lens
lens-desktop

Abbreviation

kubectl api-resources

Kind	Name	Shortnames		Kind	Name	Shortnames
Binding	bindings			LocalSubjectAccessReview	localsubjectaccessreviews
ComponentStatus	componentstatuses	cs		SelfSubjectAccessReview	selfsubjectaccessreviews
ConfigMap	configmaps	cm		SelfSubjectRulesReview	selfsubjectrulesreviews
Endpoints	endpoints	ep		SubjectAccessReview	subjectaccessreviews
Event	events	ev		HorizontalPodAutoscaler	horizontalpodautoscalers	hpa
LimitRange	limitranges	limits		CronJob	cronjobs	cj
Namespace	namespaces	ns		Job	jobs
Node	nodes	no		CertificateSigningRequest	certificatesigningrequests	csr
PersistentVolumeClaim	persistentvolumeclaims	pvc		Lease	leases
PersistentVolume	persistentvolumes	pv		EndpointSlice	endpointslices
Pod	pods	po		Event	events	ev
PodTemplate	podtemplates			FlowSchema	flowschemas
ReplicationController	replicationcontrollers	rc		PriorityLevelConfiguration	prioritylevelconfigurations
ResourceQuota	resourcequotas	quota		NodeMetrics	nodes
Secret	secrets			PodMetrics	pods
ServiceAccount	serviceaccounts	sa		IngressClass	ingressclasses
Service	services	svc		Ingress	ingresses	ing
MutatingWebhookConfiguration	mutatingwebhookconfigurations			NetworkPolicy	networkpolicies	netpol
ValidatingAdmissionPolicy	validatingadmissionpolicies			RuntimeClass	runtimeclasses
ValidatingAdmissionPolicyBinding	validatingadmissionpolicybindings			PodDisruptionBudget	poddisruptionbudgets	pdb
ValidatingWebhookConfiguration	validatingwebhookconfigurations			ClusterRoleBinding	clusterrolebindings
CustomResourceDefinition	customresourcedefinitions	crd,crds		ClusterRole	clusterroles
APIService	apiservices			RoleBinding	rolebindings
ControllerRevision	controllerrevisions			Role	roles
DaemonSet	daemonsets	ds		PriorityClass	priorityclasses	pc
Deployment	deployments	deploy		CSIDriver	csidrivers
ReplicaSet	replicasets	rs		CSINode	csinodes
StatefulSet	statefulsets	sts		CSIStorageCapacity	csistoragecapacities
SelfSubjectReview	selfsubjectreviews			StorageClass	storageclasses	sc
TokenReview	tokenreviews			VolumeAttachment	volumeattachments

Knowledge

kubectl get deployment -A kubectl get configmap -A kubectl get service -A kubectl get secret -A kubectl get event -A kubectl get pod -A	kubectl config --kubeconfig=./demo-config view --minify kubectl config view --minify kubectl config view kubectl get -n=argocd -o=yaml secret argocd-initial-admin-secret echo RE83Uk81QTU5clZyLTlsdg== | base64 --decode	kubectl get pod academia-<hash> -n chorke -o yaml kubectl describe pod academia-<hash> -n chorke kubectl logs pod academia-<hash> -n chorke -p kubectl delete pod academia-<hash> -n chorke kubectl edit pod academia-<hash> -n chorke kubectl get pod academia-<hash> -n chorke
kubectl get -n=argocd configmap kubectl get -n=argocd deployment kubectl get -n=argocd service kubectl get -n=argocd secret kubectl get -n=argocd event kubectl get -n=argocd pod	kubectl edit -n=argocd configmap argocd-rbac-cm kubectl edit -n=argocd configmap argocd-cm kubectl edit -n=argocd deployment argocd-redis kubectl edit -n=argocd service argocd-redis kubectl edit -n=argocd secret argocd-secret kubectl edit -n=argocd pod argocd-app-ctrl-0	kubectl get -n=argocd -o=yaml configmap argocd-rbac-cm kubectl get -n=argocd -o=yaml configmap argocd-cm kubectl get -n=argocd -o=yaml deployment argocd-redis kubectl get -n=argocd -o=yaml service argocd-redis kubectl get -n=argocd -o=yaml secret argocd-secret kubectl get -n=argocd -o=yaml pod argocd-app-ctrl-0
sudo ss -tulwn | grep LISTEN sudo ss -tulpn | grep LISTEN sudo ss -tulpn | grep LISTEN | grep sshd sudo ss -tulpn | grep LISTEN | grep minio sudo ss -tulpn | grep LISTEN | grep resolve	sudo lsof -i -P -n | grep LISTEN kubectl describe service academia -n academia kubectl describe service academia-auth -n academia nslookup <service-name>.<namespace>.svc.<cluster-domain>	nslookup <service-name>.<namespace>.svc.cluster.local nslookup academia-auth.academia.svc.cluster.local kubectl get all -n ingress-nginx apk add inetutils-telnet

References

Kube » Configure Access to Multiple Clusters K8s » CrashLoopBackOff » GroundCover K8s » CrashLoopBackOff » Blinkops K8s » CrashLoopBackOff » Spacelift K8s » CrashLoopBackOff » Medium Kube » Playground » Play with K8s Kube » Playground » Killercoda K8s » Ingress DNS Kube » Config Kube » Install	K8s » DNS for Services and Pods K8s » Connect to Host Database K8s » Cheapest Cluster $1/Day K8s » Ingress » ExternalName K8s » Ingress » Cert Manager K8s » Keycloak » Hostname K8s » Ingress » Letsencrypt K8s » Interactive Pod K8s » Restart Pods K8s » Lens	K8s » Resources Short Names K8s » MinIO
Docker on Windows Docker Compose Kubernetes Minikube ZA Proxy Docker JMeter Helm Istio	Snyk Vulnerability DB Sysdig