Containers with the same image version but with different configs

Question

Is there a way to have an application with 2 containers with the same image version but with different name and resources on OpenShift?

For example: In the same namespace, given a micro service with set with replicas: 6, with the metada name "app-banking", I would like to have 3 pods with envs ABC and name "app-banking-aaa-<pod_hash>", and other 3 pods with name "app-banking-bbb<pod_hash> and envs VXZ.

Didn't find anything like this on the internet.

Since we have two Kafka Bootstraps-servers, we have some consumers services that we are trying to implement "cross-broker" solution, in the same namespace.

So 3 pods will have envs to connect to Bootstrap-Server1 and other 3 pods to Bootstrap-Server2.

Appreciate the help.

Answer 1

When you deploy an application on OpenShift/Kubernetes, you need to create Deployments*1 resource on the cluster.

Deployments is one of the resources in Kubernetes and helps you to manage your application (Pod). Deployments have fields to specify a container image url and environment variables. So that it is easy to deploy applications using same container images but using different environment variables. Here is an example.

Application app-baking-aaa-<pod_hash>

apiVersion: apps/v1
kind: Deployment
metadata:
  name: app-banking-aaa
  labels:
    app: app-banking-aaa
spec:
  replicas: 3
  selector:
    matchLabels:
      app: app-banking-aaa
  template:
    metadata:
      labels:
        app: app-banking-aaa
    spec:
      containers:
      - name: app-banking
        image: https://path-to-your-registry/your-app:tag1
        env:
        - name: ABC
          value: abc

Application app-banking-bbb-<pod_hash>

apiVersion: apps/v1
kind: Deployment
metadata:
  name: app-banking-bbb
  labels:
    app: app-banking-bbb
spec:
  replicas: 3
  selector:
    matchLabels:
      app: app-banking-bbb
  template:
    metadata:
      labels:
        app: app-banking-bbb
    spec:
      containers:
      - name: app-banking
        image: https://path-to-your-registry/your-app:tag1
        env:
        - name: VXZ
          value: vxz

You many need to add more fields on the deployment however, the above deployments could help you to understand what you need to do.

I think you also need to search ConfigMap and Secrets resource for defining environment variables in Deployments.

*1: https://kubernetes.io/docs/concepts/workloads/controllers/deployment/