Posted on Feb 22, 2021 • Edited on Feb 26, 2021

Deploying a Simple NodeJS Microservice using CDK8s

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 v0.0.7 cdk8s-plus-17 v1.0.0-beta.8

Initialize CDK8s project

mkdir cdk8s-node-app && cd cdk8s-node-app cdk8s 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: v1 data: 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 6379 kind: ConfigMap metadata: name: redis-redis-conf namespace: default --- apiVersion: v1 kind: Service metadata: labels: app: redis name: redis namespace: default spec: ports: - port: 6379 targetPort: 6379 selector: app: redis type: ClusterIP --- apiVersion: apps/v1 kind: StatefulSet metadata: labels: app: redis name: redis namespace: default spec: 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/v1 kind: Deployment metadata: name: microservice-deployment-c89e8760 namespace: default spec: 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.