Introduction

Amazon Elastic Kubernetes Service (EKS) is a fully managed service that makes it easy to run Kubernetes clusters on AWS. One of the key advantages of using EKS is its integration with various AWS services through addons. These addons enhance the capabilities of your Kubernetes clusters, making them more powerful, efficient, and easier to manage.

In this article, we will discuss the available addons in Amazon EKS, explain what they do, and identify which ones are provided by default versus those that need to be manually installed and configured.

What Are EKS Addons?

EKS Addons are pre-packaged and pre-configured software components that integrate with your EKS clusters. These addons are designed to automate critical functions like networking, storage, monitoring, security, and service discovery within the Kubernetes environment.

The primary benefit of EKS addons is that they are fully managed by AWS, which means AWS takes care of updates and patches for you. This reduces the operational overhead of managing Kubernetes components, helping you focus on building and deploying applications rather than maintaining the underlying infrastructure.

Default Addons in Amazon EKS

When you create an Amazon EKS cluster, a few essential addons are automatically provided by AWS. These default addons are pre-installed and managed by AWS, ensuring that your Kubernetes cluster is operational without needing to manually configure them.

1. CoreDNS

• Purpose: CoreDNS is the default DNS service used in EKS for service discovery and DNS resolution. It enables pods and services to communicate with each other using DNS names instead of IP addresses (e.g., my-service.default.svc.cluster.local).

• How it works: CoreDNS resolves Kubernetes service names to their corresponding internal IP addresses. This helps in seamless communication between services in a Kubernetes environment.

• Why it's important: DNS is vital for pod-to-pod communication in Kubernetes. With CoreDNS, you don’t need to manage IP addresses manually, simplifying service discovery in your cluster.

2. Kube Proxy

• Purpose: Kube Proxy is responsible for managing network communication within the Kubernetes cluster. It creates rules that allow communication between pods and services by routing network traffic to the appropriate endpoints.

• How it works: Kube Proxy uses iptables or IPVS (depending on the configuration) to route traffic to the correct pods, ensuring proper load balancing and efficient communication within the cluster.

• Why it's important: Kube Proxy ensures that traffic is correctly routed between services, which is crucial for maintaining a stable and reliable application environment within the Kubernetes cluster.

3. Amazon VPC CNI (Container Network Interface)

• Purpose: The Amazon VPC CNI plugin integrates the Kubernetes networking layer with your Amazon Virtual Private Cloud (VPC). It assigns VPC IP addresses to Kubernetes pods, enabling them to directly communicate with other AWS resources (like EC2 instances and load balancers).

• How it works: By assigning a unique IP address from the VPC to each pod, the VPC CNI allows your Kubernetes environment to seamlessly interact with the AWS network and other AWS resources, without requiring complex network routing.

• Why it's important: VPC CNI simplifies networking in EKS, providing native AWS networking capabilities and ensuring better scalability, flexibility, and security for communication between pods and AWS resources.

These three addons — CoreDNS, Kube Proxy, and Amazon VPC CNI — are automatically included when you create an EKS cluster. AWS ensures that they are kept up to date and operational, reducing the need for manual intervention.

Optional Addons in Amazon EKS

While CoreDNS, Kube Proxy, and VPC CNI are provided by default, there are several other powerful optional addons that can enhance your cluster’s capabilities. These addons need to be manually installed and configured based on your specific use cases, such as scaling, monitoring, storage, and security.

Here are some of the most popular optional addons for EKS:

1. AWS Load Balancer Controller

• Purpose: This controller helps you integrate AWS Elastic Load Balancers (ELB) with Kubernetes services, including Application Load Balancer (ALB) and Network Load Balancer (NLB).

• Features:

  • Automatic provisioning and management of AWS load balancers for Kubernetes services.

  • Integration with Ingress resources for ALB-based traffic routing.

  • Support for both internal and external load balancing.

2. IAM for Service Accounts (IRSA)

• Purpose: IAM Roles for Service Accounts (IRSA) allows you to assign AWS IAM roles to Kubernetes service accounts, enabling secure and granular access to AWS resources for your pods.

• Features:

  • Helps pods authenticate to AWS services using IAM roles associated with Kubernetes service accounts.

  • Reduces the need for managing sensitive credentials in Kubernetes secrets.

3. Amazon EBS CSI Driver

• Purpose: The EBS CSI (Container Storage Interface) driver integrates Amazon Elastic Block Store (EBS) volumes with Kubernetes, enabling persistent storage for workloads.

• Features:

  • Provides dynamic provisioning and management of EBS volumes for Kubernetes pods.

  • Supports features like volume resizing, snapshots, and multi-attach for high-availability setups.

4. Amazon EFS CSI Driver

• Purpose: The EFS CSI (Container Storage Interface) driver integrates Amazon Elastic File System (EFS) with Kubernetes for scalable, shared file storage.

• Features:

  • Allows you to mount EFS volumes into Kubernetes pods.

  • Provides shared file storage, making it ideal for use cases like shared file systems or cross-pod communication.

5. CloudWatch Agent

• Purpose: The CloudWatch Agent addon collects metrics, logs, and system-level information from your EKS nodes and workloads, sending it to Amazon CloudWatch for centralized monitoring and alerting.

• Features:

  • Helps monitor the performance of your Kubernetes cluster and applications.

  • Provides custom log and metric collection, giving insights into application behavior and resource consumption.

6. Prometheus and Managed Grafana

• Purpose: This integration allows you to monitor the health and performance of your Kubernetes workloads using Amazon Managed Grafana and Prometheus.

• Features:

  • Prometheus collects metrics from Kubernetes clusters and workloads.

  • Amazon Managed Grafana enables you to visualize these metrics on interactive dashboards for easy analysis and alerting.

7. AWS X-Ray Daemon

• Purpose: The AWS X-Ray Daemon addon enables you to trace and analyze requests as they travel through your microservices, providing visibility into performance bottlenecks and errors.

• Features:

  • Helps identify issues in application performance and latency.

  • Useful for debugging microservices in a distributed system environment.

8. Kubernetes Metrics Server

• Purpose: The Metrics Server collects and provides resource usage data (CPU, memory, etc.) for your Kubernetes cluster. This is essential for horizontal pod autoscaling and monitoring.

• Features:

  • Provides key metrics for autoscaling and resource optimization.

  • Helps track pod resource consumption for efficient management.

9. Cluster Autoscaler

• Purpose: The Cluster Autoscaler automatically adjusts the number of worker nodes in your EKS cluster based on resource usage.

• Features:

  • Scales your cluster up when resource usage increases, adding new nodes.

  • Scales your cluster down by removing unused nodes when resource demand decreases.

10. AWS Secrets and Configuration Provider (ASCP)

• Purpose: This addon allows Kubernetes to securely access AWS Secrets Manager and Systems Manager Parameter Store to retrieve sensitive information such as database credentials, API keys, and configuration settings.

• Features:

  • Eliminates the need to store secrets within Kubernetes, improving security.

  • Simplifies secret management by integrating with AWS native services.

Conclusion

Amazon EKS provides a robust set of default addons that are essential for managing the core functions of your Kubernetes cluster, such as CoreDNS, Kube Proxy, and Amazon VPC CNI. These are automatically included and managed by AWS, ensuring a seamless experience for users.

In addition to the default addons, there are several optional addons available for EKS that can help you enhance your cluster’s performance, security, monitoring, and scalability. Whether you're looking to integrate persistent storage, implement service account roles, or monitor your workloads, EKS addons offer a wide range of capabilities to fit your specific needs.

By leveraging both the default and optional addons, you can build and manage more powerful, secure, and efficient Kubernetes clusters in AWS, enabling better service delivery for your cloud-native applications.