Getting Started with Amazon EKS: Managed Kubernetes on AWS

Published May 18, 2021 · by Eric Wilson · in aws

An introduction to Amazon EKS (Elastic Kubernetes Service). Learn what EKS is, how it simplifies running Kubernetes on AWS, and understand the core components of the EKS architecture.

Kubernetes has won the container orchestration war. It has become the standard, open-source platform for automating the deployment, scaling, and management of containerized applications. However, running a production-ready Kubernetes cluster yourself can be incredibly complex. You have to manage the control plane, handle upgrades, and ensure high availability.

This is where Amazon EKS (Elastic Kubernetes Service) comes in. EKS is a managed Kubernetes service that makes it easier to run Kubernetes on AWS without needing to install, operate, and maintain your own Kubernetes control plane.

What Does EKS Manage for You?

The most complex part of a Kubernetes cluster is the control plane. The control plane is responsible for making global decisions about the cluster (e.g., scheduling containers) and for detecting and responding to cluster events. It consists of several components, including etcd, the API server, the scheduler, and the controller manager.

With EKS, AWS manages the entire control plane for you across multiple AWS Availability Zones, ensuring high availability. AWS automatically handles patching, scaling, and backups of the control plane, freeing you to focus on your applications.

You are still responsible for the data plane, which is the set of worker nodes (EC2 instances) where your containers actually run.

The Architecture of an EKS Cluster

An EKS cluster consists of two main parts:

  1. The EKS Control Plane: Managed by AWS. It runs in an AWS-managed VPC and is exposed to you through a secure endpoint.

  2. The Worker Nodes: These are EC2 instances that you run in your own VPC. These nodes register with the EKS control plane and are where your application's pods (groups of one or more containers) are scheduled to run.

Ways to Manage Worker Nodes

You have a few options for managing your worker nodes:

  • Self-Managed Nodes: You can manually provision and manage your EC2 instances and register them with the control plane. This gives you the most control but also requires the most operational effort.

  • Managed Node Groups: This is the most common approach. With managed node groups, you define a configuration (e.g., instance type, desired size), and EKS automatically provisions and manages the EC2 instances for you. It handles rolling updates and graceful draining of nodes when you update the group.

  • AWS Fargate: You can also run your Kubernetes pods on AWS Fargate. With Fargate, you don't manage any worker nodes at all. You just define your pods, and Fargate runs them for you. This is the serverless way to run Kubernetes.

Getting Started with eksctl

The easiest way to create and manage an EKS cluster is with eksctl, a simple command-line tool developed by Weaveworks and AWS. With a single command, eksctl can provision an entire EKS cluster, including the control plane and worker nodes.

Example: Create a basic EKS cluster

# This single command will create a new EKS cluster named 'my-cluster'
# in the 'us-west-2' region with a managed node group.
eksctl create cluster \
--name my-cluster \
--region us-west-2 \
--nodegroup-name standard-workers \
--node-type t3.medium \
--nodes 3 \
--nodes-min 1 \
--nodes-max 4

Once the cluster is created, eksctl will automatically configure your kubectl command-line tool to connect to it.

EKS vs. ECS

AWS offers another popular container orchestrator: ECS (Elastic Container Service). So when should you choose EKS over ECS?

  • Choose EKS if:

    • You are already using Kubernetes or have a team with Kubernetes expertise.
    • You want to avoid vendor lock-in and have the flexibility to run your workloads on other cloud providers or on-premises.
    • You need the full power and rich ecosystem of the open-source Kubernetes community.

  • Choose ECS if:

    • You are new to container orchestration and want a simpler, more AWS-native experience.
    • You want the tightest possible integration with other AWS services.
    • You prefer a simpler learning curve.

Conclusion

Amazon EKS provides a powerful and robust platform for running production-grade Kubernetes on AWS. By offloading the complexity of managing the control plane, EKS allows you to leverage the power of the Kubernetes ecosystem without the associated operational headache. Whether you are migrating existing Kubernetes workloads to AWS or starting fresh, EKS is the standard for running containerized applications at scale in the cloud.

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