add k8s

docs/source/index.rst

@@ -90,6 +90,7 @@ The organization of this site is as following:
    reference/commands/git-commands
    reference/commands/vim-commands
    reference/commands/vagrant
+   reference/commands/k8s
 
 
 .. toctree::

docs/source/reference/commands/k8s.md

@@ -0,0 +1,181 @@
+# K8S
+
+[Overview of kubectl](https://kubernetes.io/docs/reference/kubectl/overview/)
+
+## Help
+
+```bash
+kubectl --help
+kubectl get nodes --help
+```
+
+## Top `kubectl` commands
+
+* use on node, pods, deployments
+
+```bash
+kubectl get
+kubectl get -o wide
+kubectl describe
+kubectl logs
+kubectl exec
+kubectl exec -ti
+```
+
+## Start with Minikube
+
+```bash
+minikube version
+minikube start
+minikube ip
+
+kubectl version
+kubectl cluster-info
+
+kubectl get nodes
+```
+
+start minikube
+
+```bash
+# from start.sh for https://kubernetes.io/docs/tutorials/hello-minikube/
+minikube version
+minikube start --wait=false
+minikube addons enable dashboard
+kubectl apply -f /opt/kubernetes-dashboard.yaml
+minikube status
+```
+
+## Deployment
+
+```bash
+# view config
+kubectl config view
+
+# open dashboard
+minikube dashboard
+
+## create a deployment
+# add `--expose` to create a service at the same time
+kubectl create deployment <some-name> --image=<some-image>
+
+# view deployments
+kubectl get deployments
+# view pods
+kubectl get pods
+# view events
+kubectl get events
+# view services
+kubectl get services
+
+# view pod and services
+kubectl get pod,svc -n kube-system
+# view with template
+kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}'
+```
+
+## Service
+
+Service Types (in ServiceSpec)
+
+* ClusterIP (default)
+* NodePort
+* LoadBalancer
+* ExternalName (1.7 or higher of `kube-dns`)
+
+```bash
+# expose (create) Service outside of the cluster
+kubectl expose deployment hello-node --type=LoadBalancer --port=8080
+kubectl expose deployment/hello --type="NodePort" --port=8080
+
+## LoadBalancer type makes Services in minikube accessible via:
+## minikube service <some-service>
+
+# get NodePort (output has no newline)
+kubectl get services/<some-service> -o go-template='{{(index .spec.ports 0).nodePort}}'
+kubectl get svc <some-service> -o go-template='{{(index .spec.ports 0).nodePort}}'
+```
+
+## Proxy
+
+```bash
+# forward communication to in-cluster private network
+# ctrl-C to stop
+kubectl proxy
+
+# get proxy node name via:
+kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}'
+# node will be accessible via route:
+http://localhost:8001/api/v1/namespaces/default/pods/$POD_NAME/proxy/
+```
+
+## Addons
+
+```bash
+# currently supported addons
+minikube addons list
+minikube addons enable <some-addon>
+minikube addons disable <some-addon>
+```
+
+## Delete
+
+```bash
+kubectl delete service <some-service>
+kubectl delete service -l <some-service-label>
+kubectl delete deployment <some-deployment>
+
+# stop minikube VM
+minikube stop
+
+# delete minikube VM
+minikube delete
+```
+
+## Exec
+
+```bash
+kubectl exec <some-pod-name> env
+kubectl exec -ti <some-pod-name> bash
+```
+
+## Labels
+
+[Labels and Selectors](https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/)
+
+Query
+
+```bash
+# example way to get labels of deployments
+kubectl describe deployment
+# query list of Pods
+kubectl get pods -l <some-label>
+```
+
+Change
+
+```bash
+kubectl label pod <some-pod-name> app=v0
+```
+
+## Scale
+
+[Horizontal Pod Autoscale](https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/)
+
+```bash
+# set 0 to remove all replicas
+kubectl scale deployment <some-deployment> --replicas=4
+```
+
+## Update
+
+```bash
+kubectl set image --help
+kubectl set image deployments <some-resource> <some-container>=<some-target-container-image>:v2
+
+# check rollout status
+kubectl rollout status <some-resource>
+
+# rollback
+kubectl rollout undo <some-resource>
+```