Forget it. Its not for you. Just some kubernetes configuration exercises.
- po : PODS
- rs: replicasets
- deploy: deployments
- svc : services
- ns : namespaces
- netpol: network policies
- pv: persistent volumes
- pvc: persistent volume claims
- sa : service accounts
List PODs:
$ kubectl get pods
Show POD info:
$ kubectl describe pod <POD NAME>
Stop a POD:
$ kubectl stop pod nginx-7cdbd8cdc9-wzht9
Run a POD from a docker image
$ kubectl run nginx --image nginx
Create from yaml
$ kubectl create -f service-nodeport-definition.yaml
List services
$ kubectl get services
Create from yaml
$ kubectl create -f service-clusterip-definition.yaml
List services
$ kubectl get services
Create from yaml
$ kubectl create -f pod-definition.yml
Update POD using yaml
:
# kubectl apply -f pod-definition.yml
Create from yaml
$ kubectl create -f [cron]job-definition.yml
Update POD using yaml
:
# kubectl apply -f [cron]job-definition.yml
Create from yaml
$ kubectl create -f rc-definition.yml
Update replication controller using yaml
:
# kubectl replace -f rc-definition.yml
List replication controllers
$ kubectl get replicationcontroller
Create from yaml
$ kubectl create -f replicaset-definition.yml
Update replica set using yaml
:
# kubectl replace -f replicaset-definition.yml
Delete:
# kubectl delete replicaset myapp-replicaset
Edit:
# kubectl edit replicaset myapp-replicaset
List replica set
$ kubectl get replicaset
To scale:
$ kubectl scale --replicas=6 -f replicaset-definition.yml
or using replicaset name: $ kubectl scale --replicas=6 replicaset myapp-replicaset
Apply from yaml
$ kubectl apply -f deployment-definition.yml
Create dev
from yaml
$ kubectl apply -f namespace-definition.yml
Create dev
from kubectl:
$ kubectl create namespace dev
Get resources from a specific namespace:
$ kubectl get pods --namespace=dev
Switching permanently to another namespace:
$ kubectl config set-context $(kubectl config current-context) --namespace=dev
Get resources from all namespaces:
$ kubectl get pods --all-namespaces
Create from yaml
$ kubectl apply -f resource-quota.yml
Install Dashboard:
$ kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v1.10.1/src/deploy/recommended/kubernetes-dashboard.yaml
Access Dashboard at:
$ kubectl proxy
List Dashboard PODs:
kubectl get secret,sa,role,rolebinding,services,deployments --namespace=kube-system | grep dashboard
Remove all Dashboard PODS at once:
kubectl delete deployment kubernetes-dashboard --namespace=kube-system
kubectl delete service kubernetes-dashboard --namespace=kube-system
kubectl delete role kubernetes-dashboard-minimal --namespace=kube-system
kubectl delete rolebinding kubernetes-dashboard-minimal --namespace=kube-system
kubectl delete sa kubernetes-dashboard --namespace=kube-system
kubectl delete secret kubernetes-dashboard-certs --namespace=kube-system
kubectl delete secret kubernetes-dashboard-key-holder --namespace=kube-system
To Authenticate Using Token
Create a new ServiceAccount
kubectl create serviceaccount k8sadmin -n kube-system
Create a ClusterRoleBinding with Cluster Admin Privileges
kubectl create clusterrolebinding k8sadmin --clusterrole=cluster-admin --serviceaccount=kube-system:k8sadmin
Then you should Generate a token:
$ kubectl get secret -n kube-system | grep k8sadmin | cut -d " " -f1 | xargs -n 1 | xargs kubectl get secret -o 'jsonpath={.data.token}' -n kube-system | base64 --decode
Now you can access it via http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/ , then select authenticate via TOKEN and paste the generated Token in the previous step.
$ kubectl set image deployment/my-deployment some-image=new-image:1.2
$ kubectl rollout status deployment/myapp-deployment
$ kubectl rollout history deployment/myapp-deployment
$ kubectl rollout undo deployment/myapp-deployment
$ kubectl describe deployment
- recreate: terminate the old version and release the new one
- ramped: release a new version on a rolling update fashion, one after the other
- blue/green: release a new version alongside the old version then switch traffic
- canary: release a new version to a subset of users, then proceed to a full rollout
- a/b testing: release a new version to a subset of users in a precise way (HTTP headers, cookie, weight, etc.). A/B testing is really a technique for making business decisions based on statistics but we will briefly describe the process. This doesn’t come out of the box with Kubernetes, it implies extra work to setup a more advanced infrastructure (Istio, Linkerd, Traefik, custom nginx/haproxy, etc).
Possible values Always, OnFailure, and Never. The default value is Always.
Using NGINX as ingress controller:
- Deployment: nginx-ingress-controller.yaml
- Service: nginx-nodeport-service.yaml
- ConfigMap: nginx-configuration.yaml
- Auth: nginx-serviceaccount.yaml
Example for a demo app called myapp
: ingress-sample-resource-to-myapp.yaml. Another exeample using paths is located at ingress-sample-resource-to-myapp-with-rules.yaml.
To get all ingress services:
$ kubectl describe ingress ingress-myapp
ingress-networkpolicy.yaml
To list volumes:
$ kubelctl get volume
$ kubelctl get persistentvolume
To list claims:
$ kubectl get persistentvolumeclaim
- efemeral:
volumes.yml
- persistent:
persistent-volume.yml
- persistent claims:
persistent-volume-claim.yml