Call endpoint periodically from kubernetes cron jon

Question

I have a web app running on one of the docker container as apart of my kubernetes cluster. The app has an end point which has be called periodically. The app runs at multiple nodes but I want only a specific node to initiate the task mentioned by the endpoint.

How am I supposed to achieve this?

Answer 1

Cron job would be appropriate to use. Here's an example of 3 nginx pods accepting all traffic, every minute, a Job curls 1 of the 3 pods (always the same pod).

apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: main
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80
---
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: singleton
  labels:
    app: nginx
    special: singleton
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
      special: singleton
  template:
    metadata:
      labels:
        app: nginx
        special: singleton
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        ports:
        - containerPort: 80
---
kind: Service
apiVersion: v1
metadata:
  name: allpods
spec:
  selector:
    app: nginx
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80

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