I wrote small application that support clustering with Akka Cluster. I want to deploy it to Kubernetes with support scaling. This is my docker-compose.yml file:

version: '3.5'

networks:
  cluster-network:

services:
  seed:
    networks:
      - cluster-network
    image: akka-cluster-server
    ports:
      - '2552:2552'
      - '8000:8000'
    environment:
      SERVER_IP: 0.0.0.0
      CLUSTER_IP: seed
      CLUSTER_SEED_IP: seed

  node1:
    networks:
      - cluster-network
    image: akka-cluster-server
    ports:
      - '8001:8000'
    environment:
      SERVER_IP: 0.0.0.0
      CLUSTER_IP: node1
      CLUSTER_PORT: 1600
      CLUSTER_SEED_IP: seed
      CLUSTER_SEED_PORT: 2552

  node2:
    networks:
      - cluster-network
    image: akka-cluster-server
    ports:
      - '8002:8000'
    environment:
      SERVER_IP: 0.0.0.0
      CLUSTER_IP: node2
      CLUSTER_PORT: 1600
      CLUSTER_SEED_IP: seed
      CLUSTER_SEED_PORT: 2552

There is three instances that share network among themselves. Note that node1 and node2 use seed's DNS name to connect. I wrote simple deployment and service.

Deployment:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: akka-cluster
spec:
  selector:
    matchLabels:
      app: akka-cluster
  replicas: 2
  template:
    metadata:
      labels:
        app: akka-cluster
    spec:
      containers:
      - name: server-seed
        image: akka-cluster-server
        imagePullPolicy: Never
        ports:
        - containerPort: 8000
        - containerPort: 2552
        env:
        - name: SERVER_IP
          value: 0.0.0.0
        - name: CLUSTER_IP
          valueFrom:
            fieldRef:
              fieldPath: status.podIP
        - name: CLUSTER_SEED_IP
          valueFrom:
            fieldRef:
              fieldPath: status.podIP
        - name: CLUSTER_PORT
          value: "1600"
        - name: CLUSTER_SEED_PORT
          value: "2552"

Service:

apiVersion: v1
kind: Service
metadata:
  name: akka-cluster-service
spec:
  type: LoadBalancer
  selector:
    app: akka-cluster
  ports:
    - protocol: TCP
      port: 8080
      targetPort: 8000

Note that in this case containers will connect to self (CLUSTER_SEED_IP) instead of seed node when you will scale replicas.

How to correct translate my docker-compose.yml to Kubernetes deployment/service?