Demo Application: BookStore App services on K8S

Follows micro-services approach. Run locally using docker-compose and traefik as loadbalancer/proxy; and on Kubernetes (DigitalOcean Managed).

Announcement: Course on Kubernetes

If you're want to start deploying your containers to Kubernetes, especially on AWS EKS, check this course on Kubernetes that walkthrough creating Kubernetes cluster on AWS EKS using Terraform and deploying multiple related containers applications to Kubernetes and more. https://courses.devteds.com/kubernetes-get-started

Code directory

mkdir -p ~/proj
cd ~/proj
git clone git@github.com:devteds/demo-apps-on-k8s.git

Run locally

cd ~/proj/demo-apps-on-k8s/local

# one time
docker network create demoapp

docker-compose up
# on a separate terminal window
docker-compose ps

Once shopapi is up, run schema migration script and seed some test data

docker-compose exec shopapi rails db:migrate
docker-compose exec shopapi rails db:seed

Once all the services start up,

open http://localhost

• http://localhost => routes to website service
• Clicking on Shop goes to http://localhost/shop => routes to shopui service
• Shopping page calls http://localhost/api/books => routes to shopapi service

Note: You may change the port mapping if port 80 is taken on dev machine

On Kubernetes

Create Kubernetes cluster on DigitalOcean

DigitalOcean API Token

Signup/Login to DigitalOcean and genereate API Token

Create Kubernetes Cluster

cd ~/proj/demo-apps-on-k8s/infra
cp secret.auto.example.tfvars secret.auto.tfvars
# edit to assign DigitalOcean API token and save

Optionally edit main.tf as needed. For example, if you need to change the region or number of worker nodes or kubernetes version

terraform init
terraform plan
terraform apply

You may login to DigitalOcean and verify Kubernetes status.

Update kubeconfig for kubectl

mkdir -p ~/.kube
terraform output config > ~/.kube/config

Verify Kubernetes cluster status

kubectl get nodes
kubectl version
# this must give you both client and server version. Client is kubectl. Server is K8S api server

Service 1: Website

cd ~/proj/demo-apps-on-k8s

kubectl apply -f services/website/deploy.yaml
kubectl get deploy
kubectl get po

kubectl apply -f services/website/service.yaml
kubectl get svc
kubectl describe svc/website

Verify using port-forward

kubectl port-forward svc/website 8082:80
open http://localhost:8082

Service 2: Shopping API

Install database

helm install bookstore stable/mysql --set mysqlUser=appuser,mysqlPassword=appuser123,mysqlDatabase=bookstore

kubectl get  svc -l app=bookstore-mysql
kubectl get  po -l app=bookstore-mysql
kubectl get  deploy -l app=bookstore-mysql

Verify

kubectl run -i --tty mysql-client --image=devteds/mysql-client:5.7_b1 --restart=Never -- bash -il

mysql -uappuser -pappuser123 -hbookstore-mysql bookstore
> show tables;
> show databases;
> exit

mysql -uappuser -pappuser123 -hbookstore-mysql.default.svc.cluster.local bookstore
> exit

Configs & Secrets

kubectl apply -f services/shopapi/config.yaml
kubectl get cm
kubectl describe cm/shopapi-cm

kubectl apply -f services/shopapi/secret.yaml
kubectl get secret/shopapi-sec -o yaml

Database schema script - use Job

kubectl create -f services/shopapi/job-dbc.yaml
kubectl get job -l app=shopapi-db
kubectl describe job/shopapi-job-dbc

# delete job when complete
kubectl delete job/shopapi-job-dbc

Deployment & Service

kubectl apply -f services/shopapi/deploy.yaml
kubectl get po -l app=shopapi

kubectl apply -f services/shopapi/service.yaml
kubectl get svc -l app=shopapi

Verify

kubectl port-forward svc/shopapi 3200:3000
open http://localhost:3200/api/books

Service 3: Shopping UI

Deploy & Service

kubectl apply -f services/shopui/deploy.yaml
kubectl get po -l app=shopui

kubectl apply -f services/shopui/service.yaml
kubectl get svc -l app=shopui

You may verify using port forward but let's to integrated test using ingress

Ingress Controller

**Install controller: install Ingress controller

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.26.1/deploy/static/mandatory.yaml

Create loadbalancer services which will create LB instance on DigitialOcean and route http/https traffic to the ingress controller pod created above.

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.26.1/deploy/static/provider/cloud-generic.yaml

Verify

kubectl get pods --all-namespaces -l app.kubernetes.io/name=ingress-nginx
kubectl get svc --namespace=ingress-nginx

Runs a service and triggers a new loadbalancer IP of which will be assigned to this service as an external IP. Notice the type of this service is LoadBalancer.

Give it a minute or so and try again,

kubectl get svc/ingress-nginx -n ingress-nginx

NAME            TYPE           CLUSTER-IP       EXTERNAL-IP         PORT(S)                      AGE
ingress-nginx   LoadBalancer   10.245.203.250   <LoadBalancer IP>   80:31323/TCP,443:32325/TCP   2m

Verify the loadbalancer on Cloud provider web console. On Digital Ocean, under Networking > Loadbalancers.

Ingress resource

Ingress resource is where we define the routing requirments and rules

kubectl apply -f route/ingress.yaml
kubectl get ing

LB_IP=$(kubectl get svc/ingress-nginx -n ingress-nginx | grep ingress | awk '{print $4}')
echo $LB_IP

# website
open http://$LB_IP

# shopapi
open http://$LB_IP/api/books
open http://$LB_IP/api/books/1