[Basic] Basic in Windows#

Links#

Download the docker k8s from: https://docs.docker.com/desktop/vm-vdi/

Terms#

- Node#

A node is the smallest unit of computing hardware in Kubernetes.

- Cluster#

The cluster as a whole, instead of worrying about the state of individual nodes.
AKA many node group as a cluster.

- Container#

Just like Docker, a container references to a image.

- Pod#

References to container, a Pod will contain various container like a pool. Also, a Node will contain multiples pods.

- AKA#

Containers < Pod < Node < Cluster

- Namespace#

Different development stages / area, e.g. dev, staging, production …
Flag is -n

Commands#

- View cluster info#

# Check verion
kubectl version

# Check cluster
kubectl cluster-info

# Check pods
kubectl get pods
kubectl describe pods

# Check nodes
kubectl get nodes

# Check deployments status
kubectl get deployments

- Create a dummy samples#

# kubectl create deployment <name> --image=<image_path>
kubectl create deployment kubernetes-bootcamp --image=gcr.io/google-samples/kubernetes-bootcamp:v1

- Open proxy#

You need to open a second terminal window to run the proxy, for external connect.

kubectl proxy

- Get pod name#

kubectl get pods

# NAME                                  READY   STATUS    RESTARTS   AGE
# kubernetes-bootcamp-f95c5b745-8zzfm   1/1     Running   0          21m


# The pod name is `kubernetes-bootcamp-f95c5b745-8zzfm`

# Using this can register the name to environment
export POD_NAME="$(kubectl get pods -o go-template --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}')"

- Go it pot#

# Print env
kubectl exec "$POD_NAME" -- env

# Inside pod
kubectl exec -ti $POD_NAME -- bash

- Expose Your App (Create services)#

We have to create a Service to expose the apps.

kubectl get pods
kubectl get services

# Create services
# kubectl expose deployment/<name> --type="NodePort" --port 8080
kubectl expose deployment/kubernetes-bootcamp --type="NodePort" --port 8080

kubectl get services
kubectl describe services/kubernetes-bootcamp

# In windows 10, you have to port forward the service to minikube
minikube service list
minikube service --url kubernetes-bootcamp

# If it's on other namespace
# minikube service <name> -n <namespace_name>
minikube service --url ingress-nginx-controller -n ingress-nginx

- Expose Your App (Pod open)#

Testing a pod

# kubectl port-forward <pod_name> <Out_port>:<Inside_port>
kubectl port-forward nginx-pod 4000:80

# For delete
kubectl delete pod <name>
kubectl delete pod nginx-pod

- Rename Pod labels (inside variables)#

kubectl describe deployment

# Print regarding info
kubectl get pods -l app=kubernetes-bootcamp
kubectl get services -l app=kubernetes-bootcamp

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

# Set labels, set the "version" variables to "v1"
kubectl label pods "$POD_NAME" version=v1

# Print regarding info
kubectl describe pods "$POD_NAME"
kubectl get pods -l version=v1

- Deleting service#

# kubectl delete service -l app=<name>
kubectl delete service -l app=kubernetes-bootcamp

- Deleting ingress#

kubectl get ns 

# kubectl delete all --all -n <name>
kubectl delete all  --all -n ingress-nginx

- Scaling a Deployment#

# Print regarding info
kubectl get deployments

# Get ReplicaSet
kubectl get rs

# Scale deployments
# kubectl scale deployments/<name> --replicas=<number>
kubectl scale deployments/kubernetes-bootcamp --replicas=4

# AKA replicas means the pod numbers to be desire

# View pods
kubectl get pods -o wide
kubectl describe deployments/kubernetes-bootcamp

- Endpoints#

# Print regarding info
kubectl get endpoints

kubectl get pod -o wide

- Delete all stuff#

kubectl delete deployment,service --all

- Create Ingress#

minikube addons enable ingress

kubectl apply -f ingress.yaml

kubectl get ingress