Deploying EKS Clusters with Terraform

In today's competitive digital landscape, businesses are increasingly reliant on cloud infrastructure to deliver scalable and resilient services. However, managing this infrastructure efficiently, especially when dealing with complex container orchestration like Amazon's Elastic Kubernetes Service (EKS), can be challenging. Many organizations struggle with inconsistencies in deployment processes, resulting in increased operational costs, downtime, and slowed product delivery.

The primary challenge lies in the manual and error-prone processes of provisioning and managing infrastructure across multiple environments. These issues not only strain the technical teams but also lead to potential business risks such as reduced agility, slower time-to-market, and the inability to scale quickly in response to market demands.

This is where Terraform by HashiCorp comes into play. As the leading Infrastructure as Code (IaC) tool, Terraform enables businesses to automate and streamline the deployment of EKS clusters, ensuring consistency, reducing manual errors, and accelerating infrastructure provisioning. By adopting Terraform, organizations can enhance their operational efficiency, reduce costs, and improve their ability to meet market demands swiftly.

In this blog post, we’ll explore how to deploy EKS clusters using Terraform, providing you with a step-by-step guide that not only simplifies your technical workflows but also delivers tangible business value through improved infrastructure management.

Before diving into the deployment process, let’s first understand what Amazon EKS is. Amazon EKS is a managed service that simplifies the running of Kubernetes on Amazon Web Services (AWS) without requiring you to install, operate, and maintain your own Kubernetes control plane or nodes. It provides the flexibility of using Kubernetes without the burden of constant management, making it an excellent choice for those who want to focus on deploying and managing applications rather than the underlying infrastructure.

Terraform is an open-source IaC software tool that allows you to build, change, and version infrastructure safely and efficiently. It supports multiple service providers, including AWS, and allows users to define both low-level components such as compute instances, storage, and networking, as well as high-level components like DNS entries.

The main reasons for using Terraform with Amazon EKS include:

1. Reproducibility: Terraform allows you to create your infrastructure as code, which can be versioned and reused, providing a reliable way to reproduce your infrastructure at any point in time.
2. Management of State: Terraform tracks the state of your resources and can apply incremental changes with minimal disruption.
3. Modularity: Using Terraform modules, you can break down your configuration into reusable, manageable pieces.

Before you start deploying an EKS cluster using Terraform, you need:

• An AWS Account and AWS CLI configured on your machine.
• Terraform installed on your local machine.
• Basic knowledge of Kubernetes and AWS services.

Step-by-Step Guide to Deploying EKS Clusters with Terraform

Start by creating a project directory named terraform-infra with the following structure:

• composition: Contains the root directories in Terraform for managing and deploying all application clusters.
• shared-modules: Contains reusable Terraform modules that are shared across multiple applications, ensuring consistency and reducing duplication in infrastructure configurations.

Within the composition directory, we'll define all of our application clusters, with each cluster dedicated to a specific application. While there are alternative ways to design your infrastructure, we’ll adopt this straightforward approach for simplicity.

Each application folder includes two key directories: environments and modules.

The environments directory houses all of your application environments and their corresponding root directories, providing a structured way to manage configurations for different deployment stages.

The modules directory is dedicated to app-specific modules, such as EC2 and IAM resources, and should only contain modules relevant to that particular application. For modules that are used across multiple applications, utilize the shared-modules directory.

Within each environment's root directory, we will define our Terraform configuration files, which will specify the infrastructure for our EKS clusters.

The Terraform modules defined in Step 5 are sourced from the shared-modules directory, which contains modules intended for use across multiple applications. This approach ensures consistency and minimizes duplication in your infrastructure configurations. Here we create folders for each AWS service we will be utilizing as shown in the image below.

Here’s where the magic happens! Within the eks-infra directory in the shared-modules folder, we’re leveraging a managed EKS module located at https://registry.terraform.io/modules/terraform-aws-modules/eks/aws/latest. This module is crucial because it streamlines the deployment of all necessary AWS resources for EKS clusters, saving significant time and effort.

Using this managed EKS module is particularly valuable for several reasons:

1. Comprehensive and Tested: The managed EKS module is maintained by Terraform’s official contributors and the community, ensuring it follows best practices and is regularly updated. This reduces the risk of errors that could occur when manually creating each component individually.
2. Time Efficient: Deploying EKS involves setting up numerous components, such as VPCs, security groups, IAM roles, and worker nodes. Manually configuring these resources requires substantial time and deep knowledge of AWS services. The managed module automates this process, allowing you to deploy a fully functional EKS cluster with minimal effort.
3. Consistent: The module ensures that your EKS clusters are consistently configured across environments. By using the same module across multiple projects or environments, you minimize configuration drift and maintain a standardized setup.
4. Scalable: The managed module is designed to handle various scenarios, whether you’re deploying a small development cluster or a large production environment. It abstracts complex tasks like autoscaling, load balancing, and networking, making it easier to scale your infrastructure as needed.

In contrast, creating all EKS components separately would require manually scripting each part, which can lead to inconsistencies, potential security gaps, and a higher likelihood of misconfigurations. The managed EKS module thus offers a streamlined, reliable, and efficient way to deploy Kubernetes clusters on AWS, allowing you to focus on what truly matters—building and scaling your applications.

To finalize your setup, begin by authenticating to your AWS account. Once authenticated, navigate to the environment root directory that you initialized in Step 5. From there, initialize the Terraform configuration by running the following command:

terraform init

After initializing, apply your Terraform configuration to deploy the EKS infrastructure with:

terraform apply

This process will provision all the defined resources, bringing your EKS cluster to life. Ensure that you review the plan output before confirming the apply command to verify that everything aligns with your expectations. This final step will complete your infrastructure deployment, making your EKS clusters ready for use.

Deploying EKS clusters with Terraform streamlines your infrastructure management and scales your application deployment efforts efficiently. This guide provided a basic walkthrough of setting up EKS clusters using Terraform, which should help you get started on your journey to mastering infrastructure as code with one of the most powerful tools available today.