maxnetz/kubernetes-dev

kubernetes-dev

Prerequisites

• Homebrew https://brew.sh/

• Docker https://docs.docker.com/desktop/install/mac-install/

• gcloud command - Install the gcloud CLI | Google Cloud

  Then you will sent to website, select the user need to login with google cloud.

  gcloud auth login
  gcloud auth list
  

• kubectl command

  brew install kubectl
  

  Check that kubectl is installed

  kubectl version
  

Exercise 1 Kubernetes Basic command line

This exerise willl run under example-kubernetes folder

Connect to Kubernetes on GCP

Import config from GKE

gcloud container clusters get-credentials poc-cluster-cmmn --zone asia-southeast1-b --project poc-innovation-iot

verfiy that kubectl command is connected with selected GKE cluster

kubectl get nodes

---

Example 1 - Try to get list resources with command

Component in every namespaces

kubectl get {component} -A

Specific type and name spaces

kubectl get {component} -n {namespace}

Describe information of component

kubectl describe {component} {component_name}

Example 2 - Interaction with component

Execute command pods

kubectl exec -it {pods_name} {command}

Entering pods (bash or others depend on how docker built)

kubectl exec -it {pods_name} bash

Create / Update / Delete component (more information in deployment part)

    kubectl apply -f deployment.yaml
    kubectl delete -f deployment.yaml

Scale pods from deployment

kubectl scale --replicas=3 deployment/test

Edit resource on the fly

kubectl edit svc/docker-registry

---

Exercise 2 Try kustomize for deployment

This exerise willl run under example-kustomize folder

Build kustomize into script for deployment Example for overlays sit

kustomize build ./example-app-kustomize/overlays/sit

Deploy microservice to kubernetes by kustomize

kustomize build {path_to_kustomize} | kubectl apply -n {namespace} -f -

After this you need to try yourself for editing some of kustomize following readme.MD in example-app-kustomize

Exercise 3 From code to running service

Now if we have the http service that can running, how we can make it from nothing to running in kubernetes

* This exerise willl run under example-app, example-app-kustomize folder, This example is golang and echo.

Health check

This example is for golang The thing that we need is the http server that running and response HTTP 200 OK status. Kubernetes will try to ping that the service is running, If not running it will restart the pods

e.GET("/", func(c echo.Context) error {
    return c.String(http.StatusOK, "Health Check!")
})

Config injection

The next thing we need to do is how config injection into services

Service read config (contain both file and env example, you can select which ways to do)

	// Loading env config of path /configs/config.yaml
	viper.AddConfigPath("/configs")
	viper.AddConfigPath(".")
	viper.SetConfigName("config") // Register config file name (no extension)
	viper.SetConfigType("yaml")   // Look for specific type
	viper.ReadInConfig()

	// Try to Dump all config from file by viper
	fmt.Println(viper.AllSettings())

	// Loading env config of key SOMECONFIGKEY
	someConfig := os.Getenv("SOMECONFIGKEY")
	fmt.Printf("Env Config is : %s", someConfig)

Build docker image

The thing before we can run service in kubernetes, we need to packaging it inside the container, so we need to build the dockerfile for packaging our service.

You can see some explanation in Dockerfile

docker build -t asia.gcr.io/poc-innovation-iot/training-kube/example-app:v1.5 ./example-app

After you built the docker image, then we need to push the docker image to cloud

docker push asia.gcr.io/poc-innovation-iot/training-kube/example-app:v1.5

Deployment by kustomize

You need to ensure that image, tag that we push in the kustomization.yaml is correct

file example-app-kustomize/overlays/sit/kustomization.yaml

images:
  - name: asia.gcr.io/poc-innovation-iot/training-kube/example-app
    newTag: v1.4

Then the configuration you need to enter the require configuration

• Env - go to example-app-kustomize/overlays/sit/configs/config.env file
• File - go to example-app-kustomize/overlays/sit/configs/config.yaml file

For specifies the resources to be use example-app-kustomize/overlays/sit/patches/set_resources.yaml

resources:
    limits:
        cpu: 200m
        memory: 512Mi
    requests:
        cpu: 200m
        memory: 512Mi

Then apply the kustomize to kubernetes

kustomize build ./example-app-kustomize/overlays/sit | kubectl apply -n {namespace} -f -

Then we finished on deployment service into kubernetes