Kubernetes-traning

Namespace

• export NAMESPACE=<your_namespace>
• kubectl get namespaces
• kubectl create namespace $NAMESPACE
• kubectl config set-context kube-foundation --namespace=$NAMESPACE

Deployment

• kubectl create deployment nginx --image=nginx
• kubectl get deploy
• kubectl get rs
• kubectl get pods -o wide
• kubectl get pods --show-labels
• kubectl get deploy -o json
• kubectl get deploy -o yaml
• kubectl delete deploy nginx

From template

• kubectl apply -f deployment/nginx_deployment.yaml --record
• kubectl get deploy
• kubectl rollout status deployment nginx
• kubectl get rs
• kubectl get pods -o wide --show-labels=true
• kubectl describe deploy/nginx

Labels

• kubectl label pod … app-
• kubectl get pods -o wide --show-labels=true
• kubectl label pod ... app=nginx

Service

Deploy busybox in default namespace

• kubectl -n default create deploy busybox --image=yauritux/busybox-curl -- /bin/sh -c "while true; do sleep 30; done;"

Check DNS name

• kubectl -n default exec -it $(kubectl -n default get pods | grep busybox | awk '{print $1}') sh
• curl nginx.cdp
• exit

Deploy service

• cat services/nginx_service.yaml
• kubectl apply -f services/nginx_service.yaml
• kubectl get services
• kubectl get ep
• kubectl -n default exec -it $(kubectl -n default get pods | grep busybox | awk '{print $1}') sh
• curl nginx.cdp

Headless service

• cat services/nginx_headless_service.yaml
• cat services/nginx_headless_service.yaml | kubectl replace --force -f -
• kubectl -n default exec -it $(kubectl -n default get pods | grep busybox | awk '{print $1}') sh
• curl nginx.cdp
• nslookup nginx.cdp
• cat services/nginx_service.yaml | kubectl replace --force -f -

External service

• cat external-service/external_service.yaml
• kubectl apply -f external-service/external_service.yaml
• kubectl -n default exec -it $(kubectl -n default get pods | grep busybox | awk '{print $1}') sh
• curl service.cdp
• nslookup service.cdp
• exit
• cat external-service/external_ep.yaml
• kubectl apply -f external-service/external_ep.yaml
• kubectl -n default exec -it $(kubectl -n default get pods | grep busybox | awk '{print $1}') sh
• curl service.cdp
• exit

NodePort

• kubectl patch svc nginx -p '{"spec": {"type":"NodePort"}}'
• kubectl get svc

Ingress

• cat ingress/nginx-ingress.yaml
• kubectl apply -f ingress/nginx-ingress.yaml

Applications

Dry-run

• kubectl create deployment nginx1 --image=nginx --dry-run=true
• kubectl create deployment nginx1 --image=nginx --dry-run=true –o yaml > nginx.yaml

Environments

• cat env-variables/nginx_deployment_env.yaml
• kubectl apply -f env-variables/nginx_deployment_env.yaml
• kubectl describe deploy nginx
• kubectl exec -it $(kubectl get pods | grep nginx | awk '{print $1}' | head -1) bash
• echo $DEMO_KUBERNETES

Envs from

• cat env-from/nginx_deployment_envFrom.yaml
• kubectl apply -f env-from/nginx_deployment_envFrom.yaml
• kubectl describe deploy nginx
• kubectl exec -it $(kubectl get pods | grep nginx | awk '{print $1}' | head -1) bash
• env | grep NAMESPACE

Scheduling

Node selector

• kubectl get nodes --show-labels
• cat scheduling/nginx_nodeselector.yaml
• kubectl apply -f scheduling/nginx_nodeselector.yaml
• kubectl label node kube-slave2 type=node-selector
• kubectl get pods -o wide
• kubectl delete -f scheduling/nginx_nodeselector.yaml

Node affinity

• cat scheduling/nginx_nodeaffinity_preffered.yaml
• kubectl apply -f scheduling/nginx_nodeaffinity_preffered.yaml
• kubectl get pods -o wide
• cat scheduling/nginx_nodeaffinity_required.yaml
• kubectl apply -f scheduling/nginx_nodeaffinity_required.yaml
• kubectl get pods -o wide
• kubectl label node kube-slave1 type=node-affinity
• kubectl get pods -o wide
• kubectl edit deployments nginx-node-affinity(show anti-affinity operator NotIn)
• kubectl get pods -o wide
• kubectl delete -f scheduling/nginx_nodeaffinity_required.yaml

Pod affinity

• cat scheduling/redis_podantiaffinity.yaml
• kubectl apply -f scheduling/redis_podantiaffinity.yaml
• kubectl get pods -o wide
• kubectl scale deployment redis-cache --replicas=4
• kubectl get pods -o wide
• kubectl scale deployment redis-cache --replicas=2
• kubectl get pods -o wide
• cat scheduling/webserver_podaffinity.yaml
• kubectl apply -f scheduling/webserver_podaffinity.yaml
• kubectl scale deployment web-server --replicas=4
• kubectl get pods -o wide
• kubectl delete -f scheduling/redis_podantiaffinity.yaml
• kubectl delete -f scheduling/webserver_podaffinity.yaml

Taint and tolerations

• kubectl get node kube-master -o jsonpath='{.spec.taints[]}{"\n"} '
• kubectl get node kube-master -o jsonpath='{.spec.taints[?(@.key=="kubernetes.io/role")].value}{"\n"}'
• cat scheduling/redis_toleration.yaml
• kubectl apply -f scheduling/redis_toleration.yaml
• kubectl get pods -o wide
• kubectl scale deployment redis-cache --replicas=4
• kubectl get pods -o wide
• kubectl taint node kube-master cdp=test:NoSchedule
• kubectl get pods -o wide
• kubectl taint node kube-master cdp-
• kubectl taint node kube-master cdp=test:NoExecute
• kubectl get pods -o wide
• kubectl taint node kube-master cdp-
• kubectl delete -f scheduling/redis_toleration.yaml

Logs

• kubectl logs $(kubectl get pods | grep nginx | awk '{print $1}' | head -1)

Compute resourses

• cat resouces/nginx_resources.yaml
• kubectl apply -f resouces/nginx_resources.yaml
• kubectl describe pods $(kubectl get pods | grep nginx-resources | awk '{print $1}' | head -n 1)
• kubectl delete -f resouces/nginx_resources.yaml

Deployment update

• kubectl set image deploy nginx nginx=nginx:1.133 --record=true
• kubectl rollout status deploy nginx
• kubectl get pods
• kubectl rollout history deploy nginx
• kubectl rollout history deploy nginx --revision=2
• kubectl rollout undo deploy nginx
• kubectl rollout undo deploy nginx --to-revision=1

Kubectl explain

• kubectl explain pods.spec.containers

Config maps

• kubectl create configmap nginx-config --from-file=config-maps/index.html --from-literal=special.how=very
• cat consume-config-maps/nginx_deployment_env.yaml
• kubectl apply -f consume-config-maps/nginx_deployment_env.yaml
• cat consume-config-maps/nginx_deployment_volume.yaml
• kubectl apply -f consume-config-maps/nginx_deployment_volume.yaml

Secrets

• kubectl create secret generic db-user-pass --from-file=username=secrets/username.txt --from-file=password=secrets/password.txt
• kubectl get secret db-user-pass -o yaml
• kubectl get secret db-user-pass -o jsonpath='{.data.password}‘
• kubectl get secret db-user-pass -o jsonpath='{.data.password}' | base64 -d