Deploying a Simple NodeJS Microservice using CDK8s

#kubernetes #typescript #cdk8s #devops

Writing 200+ lines of YAML code just to deploy a Microservice on Kubernetes is a massive pain for a DevOps engineer.

CDK8s can be used to remove all that duplicate code, and make it easier to deploy your Microservice without having to write massive YAML manifests.

We also get the ability to write code using our favorite object-oriented languages.

We will be writing a sample CDK8s chart using TypeScript and opensource CDK8s constructs.

Constructs used :

@opencdk8s/cdk8s-redis-sts v0.0.7cdk8s-plus-17 v1.0.0-beta.8

Initialize CDK8s project

mkdir cdk8s-node-app && cd cdk8s-node-appcdk8s init typescript-app

Install construct libraries

npm install @opencdk8s/cdk8s-redis-sts

Edit main.ts to include our Redis db, and NodeJS app

import { Construct } from 'constructs';import { App, Chart, ChartProps } from 'cdk8s';import { MyRedis } from '@opencdk8s/cdk8s-redis-sts';import { Deployment } from 'cdk8s-plus-17';export class MyChart extends Chart {  constructor(scope: Construct, id: string, props: ChartProps = { }) {    super(scope, id, props);const redis = new MyRedis(this, 'redis', {      image: 'redis',      namespace: 'default',      volumeSize: '10Gi',      replicas: 3,      createStorageClass: false,    });new Deployment(this, "deployment", {      metadata: {        namespace: 'default',      },      containers: [{        image: "hunterthompson/node-redis-counter:latest",        name: "hello",        env: {          'REDIS_URI': {            value: redis.name          }        }      }]    })  }}const app = new App();new MyChart(app, 'microservice');app.synth();

Run Compile and Synth

npm run compile && npm run synth

The end result of the npm run synth command is a YAML manifest that you can apply using kubectl

apiVersion: v1data:  master.conf: |-    bind 0.0.0.0    daemonize no    port 6379    tcp-backlog 511    timeout 0    tcp-keepalive 300    supervised no  slave.conf: |-    slaveof redis 6379kind: ConfigMapmetadata:  name: redis-redis-conf  namespace: default---apiVersion: v1kind: Servicemetadata:  labels:    app: redis  name: redis  namespace: defaultspec:  ports:    - port: 6379      targetPort: 6379  selector:    app: redis  type: ClusterIP---apiVersion: apps/v1kind: StatefulSetmetadata:  labels:    app: redis  name: redis  namespace: defaultspec:  replicas: 3  selector:    matchLabels:      app: redis  serviceName: redis  template:    metadata:      labels:        app: redis    spec:      containers:        - command:            - bash            - -c            - |-              [[ `hostname` =~ -([0-9]+)$ ]] || exit 1              ordinal=${BASH_REMATCH[1]}              if [[ $ordinal -eq 0 ]]; then              redis-server /mnt/redis/master.conf              else              redis-server /mnt/redis/slave.conf              fi          env: []          image: redis          name: redis          ports:            - containerPort: 6379          resources:            limits:              cpu: 400m              memory: 512Mi            requests:              cpu: 200m              memory: 256Mi          volumeMounts:            - mountPath: /data              name: redis            - mountPath: /mnt/redis/              name: redis-redis-conf      terminationGracePeriodSeconds: 10      volumes:        - configMap:            name: redis-redis-conf          name: redis-redis-conf  volumeClaimTemplates:    - metadata:        name: redis        namespace: default      spec:        accessModes:          - ReadWriteOnce        resources:          requests:            storage: 10Gi        storageClassName: gp2--------apiVersion: apps/v1kind: Deploymentmetadata:  name: microservice-deployment-c89e8760  namespace: defaultspec:  replicas: 1  selector:    matchLabels:      cdk8s.deployment: microservice-deployment-c87f6fea  template:    metadata:      labels:        cdk8s.deployment: microservice-deployment-c87f6fea    spec:      containers:        - env:            - name: REDIS_URI              value: redis          image: hunterthompson/node-redis-counter:latest          imagePullPolicy: Always          name: hello          ports: []          volumeMounts: []      volumes: []

We just synthesized a 130 line YAML manifest by writing 33 lines of CDK8s code.

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Matt Coulter

Software Architect working on enabling engineers to rapidly deliver serverless-first solutions in a Fortune 100 organisation - passionate about Serverless, AWS, dev.to/cdkpatterns, TCO, and CI/CD