Running cronjob in NodeJS express triggers 3 times hosted on Google Kubernetes Engine with 3 nodes. How to run a cronjob within a node?

Question

I have a scenario where I am sending email in every 1 days with using node-cron library in nodejs. The server is hosted in GKE with three nodes. But I am getting 3 emails each day, I believe from 3 different nodes running the same scheduled function. How can I overcome this so I get email from only one node?

I tried using cluster package

if(cluster.isMaster){
   initScheduleFunctions()
}

in my index.js.

Answer 1

So your current deployment has 3 replicas:

apiVersion: apps/v1
kind: Deployment
metadata: null
name: backend-deploy
spec: null
replicas: 3
selector: null
matchLabels: null
app: app
template:
  metadata: null
  labels:
    app: app
  spec:
    containers:
      - image: 'gcr.io/vektor-dev-351106/vektor-pm-be:latest'
        name: vektor-be
        imagePullPolicy: Always
        ports:
          - containerPort: 4000

If you want to continue running your job as a Deployment, just modify replicas to 1:

apiVersion: apps/v1
kind: Deployment
metadata: null
name: backend-deploy
spec: null
replicas: 1
selector: null
matchLabels: null
app: app
template:
  metadata: null
  labels:
    app: app
  spec:
    containers:
      - image: 'gcr.io/vektor-dev-351106/vektor-pm-be:latest'
        name: vektor-be
        imagePullPolicy: Always
        ports:
          - containerPort: 4000