With Amazon Elastic Kubernetes Service (EKS), AWS offers a managed Kubernetes solution that is ideal for deploying akka-based microservices. In this post, we show how to deploy an akka cluster on AWS EKS.

What is AWS EKS?

Amazon Elastic Kubernetes Service (EKS) is a managed Kubernetes service that makes it easy to run Kubernetes on AWS. AWS takes over the management of the control plane, allowing developers to focus on their applications.

Benefits of EKS

Managed Control Plane: AWS takes care of availability and scaling
Integration with AWS Services: Seamless connection to IAM, VPC, ELB, and more
Security: Automatic security updates and integration with AWS security services
High Availability: Control plane runs across multiple Availability Zones

akka and Kubernetes - A Perfect Combination

akka is a toolkit for building highly concurrent, distributed, and fault-tolerant applications on the JVM. In combination with Kubernetes, special advantages emerge:

akka Cluster Discovery

akka offers Kubernetes-native cluster discovery with the akka-management module. Instead of static seed nodes, akka nodes can automatically find each other via the Kubernetes API.

akka.discovery {
  method = kubernetes-api
  kubernetes-api {
    pod-namespace = "default"
    pod-label-selector = "app=my-akka-app"
  }
}

Health Checks

akka-management provides HTTP endpoints for Kubernetes liveness and readiness probes:

livenessProbe:
  httpGet:
    path: /alive
    port: 8558
readinessProbe:
  httpGet:
    path: /ready
    port: 8558

Creating EKS Cluster

Prerequisites

AWS CLI configured
kubectl installed
eksctl installed

Creating Cluster with eksctl

eksctl create cluster \
  --name akka-cluster \
  --region eu-central-1 \
  --nodegroup-name standard-workers \
  --node-type t3.medium \
  --nodes 3 \
  --nodes-min 1 \
  --nodes-max 4 \
  --managed

Updating kubeconfig

aws eks update-kubeconfig --region eu-central-1 --name akka-cluster

Preparing akka Application for Kubernetes

Dockerfile

FROM openjdk:11-jre-slim
WORKDIR /app
COPY target/universal/stage/ .
EXPOSE 8080 8558 2552
CMD ["bin/my-akka-app"]

Kubernetes Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-akka-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-akka-app
  template:
    metadata:
      labels:
        app: my-akka-app
    spec:
      containers:
      - name: my-akka-app
        image: my-registry/my-akka-app:latest
        ports:
        - containerPort: 8080
          name: http
        - containerPort: 8558
          name: management
        - containerPort: 2552
          name: remoting
        livenessProbe:
          httpGet:
            path: /alive
            port: management
        readinessProbe:
          httpGet:
            path: /ready
            port: management

RBAC for Cluster Discovery

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: pod-reader
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["get", "list", "watch"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: read-pods
subjects:
- kind: ServiceAccount
  name: default
roleRef:
  kind: Role
  name: pod-reader
  apiGroup: rbac.authorization.k8s.io

Performing Deployment

# Build and push image
docker build -t my-registry/my-akka-app:latest .
docker push my-registry/my-akka-app:latest

# Create Kubernetes resources
kubectl apply -f rbac.yaml
kubectl apply -f deployment.yaml
kubectl apply -f service.yaml

# Check status
kubectl get pods
kubectl logs -l app=my-akka-app

Monitoring Cluster Status

To monitor the akka cluster status, you can use the akka-management endpoints:

kubectl port-forward svc/my-akka-app 8558:8558
curl http://localhost:8558/cluster/members

Conclusion

AWS EKS provides a solid platform for deploying akka cluster applications. The combination of managed Kubernetes infrastructure and akka’s native Kubernetes integration enables the construction of highly available, distributed systems with minimal operational effort.

At innFactory, we successfully use akka and Kubernetes in numerous projects. As AWS and Lightbend partners, we support companies in developing and operating reactive cloud applications.