Kubectl Cheat Sheet

> minikube version
> minikube start
> kubectl version
> kubectl get nodes

Run app in kubernetes

Run app in kubernetes by kubectl

> kubectl run kubernetes-bootcamp --image=docker.io/jocatalin/kubernetes-bootcamp:v1 --port=8080

also run GRPS_Sample //problematic

> kubectl run kubernetes-grpc-sample --image=maruftuhin/server_grpc_sample --port=8088

See deployments

> kubectl get deployments

run proxy and echo

> kubectl proxy

setting up POD_NAME variable

> export POD_NAME=$(kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')
> echo Name of the Pod: $POD_NAME

> curl http://localhost:8001/api/v1/proxy/namespaces/default/pods/$POD_NAME

Pods

> kubectl get pods
> kubectl describe pods
> kubectl logs $POD_NAME

Execute commands on container

settings up env variables

> kubectl exec $POD_NAME env

run a container

> kubectl exec -ti $POD_NAME bash
> exit

Services on kubernetes

> kubectl get services

create and expose new service

> kubectl expose deployment/kubernetes-bootcamp --type="NodePort" --port 8080

setting up Node Port variable

> export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{{(index .spec.ports 0).nodePort}}')
> echo NODE_PORT=$NODE_PORT

accessing POD from external

> curl host01:$NODE_PORT

accessing pod from internal

> kubectl exec -ti $POD_NAME curl localhost:8080

get description of only one deployment

> kubectl get pods -l <label>
i.e.
> kubectl get pods -l run=kubernetes-bootcamp
> kubectl get services -l run=kubernetes-bootcamp

1. setting up lable. 1st get POD NAME. then

> export POD_NAME=$(kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')
> echo Name of the Pod: $POD_NAME

2. label it

> kubectl label pod $POD_NAME app=v1

List of pods using label “app=v1”

> kubectl get pods -l app=v1

delete services with label run=kubernetes-bootcamp

> kubectl delete service -l run=kubernetes-bootcamp

Scaling

> kubectl get deployments

scale to 4 replicas. [kubernetes–bootmcamp] is name of deloyments

> kubectl scale deployments/kubernetes-bootcamp --replicas=4

current pods

> kubectl get pods -o wide

Change log

> kubectl describe deployments/kubernetes-bootcamp

find exposed ip and service

> kubectl describe services/kubernetes-bootcamp

set environment variable NODE PORT

> export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{{(index .spec.ports 0).nodePort}}')
> echo NODE_PORT=$NODE_PORT

Run this command to see which pod is serving

> curl host01:$NODE_PORT

Scale down service to 2 replicas from 4 replicas

> kubectl scale deployments/kubernetes-bootcamp --replicas=2

Description again

> kubectl get deployments
> kubectl get pods -o wide

Updating Application

> kubectl get deployments
> kubectl get pods

current image version of app

> kubectl describe pods

update the image to version 2

> kubectl set image deployments/kubernetes-bootcamp kubernetes-bootcamp=jocatalin/kubernetes-bootcamp:v2

Changes in Pods

> kubectl get pods

Verify update

service description

> kubectl describe services/kubernetes-bootcamp

setting up NODE PORT

> export NODE_PORT=$(kubectl get services/kubernetes-bootcamp -o go-template='{{(index .spec.ports 0).nodePort}}')
> echo NODE_PORT=$NODE_PORT

rollout status command to see update

> kubectl rollout status deployments/kubernetes-bootcamp

Rollback update

First deploy update tag v10 for example

> kubectl set image deployments/kubernetes-bootcamp kubernetes-bootcamp=jocatalin/kubernetes-bootcamp:v10

status

> kubectl get deployments
> kubectl get pods
> kubectl describe pods
# we can see, not all are v10 applied

rollback to previous working state

> kubectl rollout undo deployments/kubernetes-bootcamp

Run own program docker-gRPC

> docker images
> kubectl run grpc-sample3 --image=maruftuhin/server_grpc_sample:tag --port=8088
> kubectl get pods

access from internal

> kubectl proxy
> curl --data "{\"name\": \"pc1\", \"a\":2,\"b\":3}" http://localhost:8001/api/v1/proxy/namespaces/default/pods/<pods id >/echo

access from external [Expose ]

> kubectl expose deployment/grpc-sample3 --type="NodePort" --port 8088
> kubectl get services/grpc-sample3

setting $Node_Port variable. but the ports can also be used from “kubectl get services/grpc-sample3” results

> export NODE_PORT=$(kubectl get services/grpc-sample3 -o go-template='{{(index .spec.ports 0).nodePort}}')
> kubectl get services/grpc-sample3
> kubectl get nodes
> kubectl get svc grpc-sample3 -o yaml
> minikube service grpc-sample3 --url
> curl --data "{\"name\": \"pc1\", \"a\":2,\"b\":3}" http://192.168.99.100:32258/echo