How To Deploy Express With Amazon EKS

GitHub: https://github.com/fullstackbook/fullstackbook-express-eks

Learn how to deploy an Express app to Amazon EKS.

Prerequisites

Follow the getting started guide and make sure the following are installed:
- AWS CLI
- kubectl
- eksctl
https://docs.aws.amazon.com/eks/latest/userguide/getting-started.html

Initial Setup

Install Express.
```
npm init
npm install express --save
```

Create express app. app.js

const express = require("express");
const app = express();
const port = 3000;

app.get("/", (req, res) => {
  res.send("Hello World!");
});

app.listen(port, () => {
  console.log(`Example app listening on port ${port}`);
});

Create Dockerfile.

FROM node:16
WORKDIR /usr/src/app
COPY package.json ./
RUN npm install
COPY . .
CMD [ "node", "app.js" ]

Build image.
```
docker build -t express-eks .
```

Run container.

docker run -p 3000:3000 -it --rm --name express-eks-run express-eks

Elastic Container Registry (ECR) Setup

Go to Amazon ECR.
Create a repository.
Click on "View push commands".
Follow the instructions to push image.
Copy the image url.

Elastic Kubernetes Service (EKS) Setup

Create EKS cluster.

eksctl create cluster --name my-cluster --region us-west-2

Confirm communication with cluster.
```
kubectl get svc
```

Create yaml configuration. k8s.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
        - name: myapp
          image: 111111111111.dkr.ecr.us-east-2.amazonaws.com/myapp:latest
          resources:
            limits:
              memory: "128Mi"
              cpu: "500m"
          ports:
            - name: tcp
              containerPort: 3000
---
apiVersion: v1
kind: Service
metadata:
  name: myapp
spec:
  selector:
    app: myapp
  ports:
    - port: 80
      targetPort: 3000
  type: LoadBalancer

Apply manifest.
```
kubectl apply -f k8s.yaml
```
Confirm pods.
```
kubectl get pod
```

Open shell into pod.

kubectl exec -it myapp-7487b94844-wvfmn -- bash

Confirm load balancer.
```
kubectl get svc
```

Confirm load balancer domain.

nslookup af220a880523a491a991ecc793ae1da2-125775810.us-west-2.elb.amazonaws.com

Note: This might take a few minutes.

Confirm response from app.

curl af220a880523a491a991ecc793ae1da2-125775810.us-west-2.elb.amazonaws.com

Deploy Script

Use this script to deploy latest commits.

LATEST_SHA=$(git rev-parse HEAD)
docker build -t express-eks:$LATEST_SHA .
docker tag express-eks:$LATEST_SHA 207100238581.dkr.ecr.us-east-2.amazonaws.com/express-eks:$LATEST_SHA
docker push 207100238581.dkr.ecr.us-east-2.amazonaws.com/express-eks:$LATEST_SHA
kubectl set image deployment/myapp myapp=207100238581.dkr.ecr.us-east-2.amazonaws.com/express-eks:$LATEST_SHA -n default

Set up AWS Load Balancer Controller

For more complex traffic routing, see how-to-set-up-aws-load-balancer-controller.md.

Delete cluster

Delete the cluster avoid large AWS bill.

eksctl delete cluster --name my-cluster