k8s workshop

Overview

This repo contains exercises, which will help you start working with Kubernetes (k8s). It consists of:

• the source code with yaml files
• presentation with the theory and tips, how to use k8s in your daily work.

Prerequisites

• Docker
• Minikube
  • macOs: brew cask install minikube
• VirtualBox (for minikube)
  • macOs: brew cask install virtualbox
• Helm
  • macOs: brew install kubernetes-helm

Check the tools:

# --- check docker: running containers ---
docker ps

# output:
CONTAINER ID	IMAGE	COMMAND		CREATED		STATUS		PORTS		NAMES

# --- check minikube: version & run minikube ---
minikube -v
minikube start
kubectl get all

# output:
There is a newer version of minikube available (v1.0.0).  Download it here:
https://github.com/kubernetes/minikube/releases/tag/v1.0.0

To disable this notification, run the following:
minikube config set WantUpdateNotification false
😄  minikube v0.35.0 on darwin (amd64)
🔥  Creating virtualbox VM (CPUs=2, Memory=2048MB, Disk=20000MB) ...
💿  Downloading Minikube ISO ...
 184.42 MB / 184.42 MB [============================================] 100.00% 0s
📶  "minikube" IP address is 192.168.99.100
🐳  Configuring Docker as the container runtime ...
✨  Preparing Kubernetes environment ...
💾  Downloading kubelet v1.13.4
💾  Downloading kubeadm v1.13.4
🚜  Pulling images required by Kubernetes v1.13.4 ...
🚀  Launching Kubernetes v1.13.4 using kubeadm ...
⌛  Waiting for pods: apiserver proxy etcd scheduler controller addon-manager dns
🔑  Configuring cluster permissions ...
🤔  Verifying component health .....
💗  kubectl is now configured to use "minikube"
🏄  Done! Thank you for using minikube!


NAME				TYPE		CLUSTER-IP		EXTERNAL-IP		PORT(S)		AGE
service/kubernetes  ClusterIP	x.x.x.x			<none>			443/TCP		2m

# --- check helm: init & version ----
helm init
helm version

# output:
Client: &version.Version{SemVer:"v2.13.1", GitCommit:"618447cbf203d147601b4b9bd7f8c37a5d39fbb4", GitTreeState:"clean"}
Server: &version.Version{SemVer:"v2.13.1", GitCommit:"618447cbf203d147601b4b9bd7f8c37a5d39fbb4", GitTreeState:"clean"}

Branches (steps/bites)

The repository has 5 branches, called bites. Each of them provides some improvements, i.e deployments have some additional annotations. To get the most out of it, go through all the branches (bites) in a right order (bite1 -> bite2 -> bite3 -> bite4 -> bite5 ).

Prepare your environment

To start working with k8s, run these commands:

# start minikube
minikube start

# bind your local docker to the minikube one
eval $(minikube docker-env)

# enable ingress
minikube addons enable ingress

# then check
kc get po -n kube-system

# add this line to your /etc/hosts
...
192.168.99.100       backend.domain.com frontend.domain.com

Bite1

In the first bite, we will deploy the database and backend.

Run these commands to create your first deployments, services, and ingress:

# build backend docker image
cd backend
docker build -t backend:v1 .

# deploy
kubectl apply -f database/deployment/database-deployment.yaml
kubectl apply -f database/deployment/service-deployment.yaml

kubectl apply -f backend/deployment/backend-deployment.yaml
kubectl apply -f backend/deployment/backend-service.yaml
kubectl apply -f backend/deployment/backend-ingress.yaml

Proof:

# display all resources deployed on k8s
kubectl get all

# display deployments/pods/services/ingresses deployed on k8s
kubectl get deployment # or kubectl get deployments or kubectl get deploy
kubectl get pod # or kubectl get pods or kubectl get po
kubectl get service # or kubectl get services or kubectl get svc
kubectl get ingress # or kubectl get ingresses or kubectl get ing

Proof:

Go to minikube dashboard and see your deployments there.

Proof:

Go to backend.domain.com. Under the main root (/), you should see: "backend works".

If you are familiar with MongoDB and want to add some data to the running mongo container, go to Play with Mongo in Advanced.md file.

Bite2

In the bite2, we will deploy frontend using similar commands as in the first bite. Before that, we need to build a docker image for the frontend application:

# build backend docker image
cd frontend
docker build -t frontend:v1 .

This docker images can take some time since npm install is running inside. If you want to save your time in the future (you will build the image a couple of times), replace the Dockerfile with the following one:

FROM nginx

COPY ./build /etc/nginx/html
COPY ./nginx.conf /etc/nginx/nginx.conf
WORKDIR /etc/nginx

EXPOSE 80

CMD ["nginx", "-g", "daemon off;"]

and then run:

cd frontend

# install dependencies
npm install

# build production code
npm run build

# build backend docker image
docker build -t frontend:v1 .

At the end, deploy the frontend app:

kubectl apply -f frontend/deployment/frontend-deployment.yaml
kubectl apply -f frontend/deployment/frontend-service.yaml
kubectl apply -f frontend/deployment/frontend-ingress.yaml

Proof:

Go to frontend.domain.com . Now, we should be able to open the frontend app in the browser. The problem will be (as always ;)) with the CORS. Go to bite3 to learn how to fix it.

Bite3

We have 2 options to fix the issue with CORS and allow the frontend app to fetch the data from the backend:

• we can install cors library and use it in the server.js file, in the backend,
• or, we can put the annotation in the backend ingress, which will turn on the CORS for us. In the bite3, we will go with the second approach.

Rebuild your ingress:

# deploy new ingress (with cors)
kubectl apply -f backend/deployment/backend-ingress.yaml

Proof:

Go to frontend.domain.com . Now, we should not have any CORS problem.

Bite4

The bite4 is about Helm, which is a package manager for Kubernetes. In this small project, we have 3 deployments (database, backend, frontend), where each of them has 2 - 3 files. To have the whole application working as we suspect, we have to run kubectl apply ~8 times.

Let's imagine, that you have more than one app, more than one service, more than one database. Do you want to deploy them (every service, ingress, deployment, and so on) as you did it before? Helm comes for the rescue!

# run tiller
helm init

# deploy everything at once
helm install helm-deployment

Proof:

# display all resources deployed on k8s
kubectl get all

# display list of helm releases
helm list

Bite5

The last bite is an exercise for you. Inside the exercise directory, you will find a small service with Dockerfile. All you need to do is build the image and create yamls to deploy the app on k8s!

Good luck!