Key Lessons and Mistakes from Setting Up EKS Clusters

Setting up an Amazon Elastic Kubernetes Service (EKS) cluster is a common task for cloud-native organizations, but it’s not without its challenges. Many professionals, from cloud engineers to Kubernetes experts, have faced various obstacles during their EKS setup journey. These challenges often lead to important lessons and insights. Below are some of the most common mistakes encountered by teams when setting up EKS clusters, along with the key takeaways learned from those experiences.

Mistake #1: Underestimating Networking Complexity

Lesson Learned: Planning the network architecture for EKS clusters is more complex than it initially appears. One of the most common mistakes is underestimating the intricacies of VPC setup, subnet design, and IP address management.

• Issue: Many teams started with smaller CIDR blocks for pod IP addresses, only to face IP exhaustion issues as their cluster scaled. This forced them to rework their network design, leading to downtime and wasted effort.

• Takeaway: Ensure that larger CIDR blocks (e.g., /16) are allocated from the beginning. This provides enough IP space for pods and reduces the risk of IP address exhaustion as the cluster grows. A thorough network planning phase is essential before launching any workloads. Additionally, AWS provides the following options for managing IP address allocation more effectively: Increasing IP Addresses for EKS Pods - if you're running out of IP addresses for your pods in a VPC, you can follow the procedure for increasing IP addresses, as outlined in AWS documentation and Using a Custom Networking Setup - for more advanced network configurations, you can implement custom networking to better control pod IP allocation.

Mistake #2: Over-Provisioning Resources

Lesson Learned: It’s easy to assume that more resources are better, especially when setting up the first EKS cluster. However, many teams faced underutilized resources that unnecessarily drove up costs.

• Issue: Early configurations often led to over-provisioned EC2 instances. While the extra capacity seemed prudent, it resulted in significant inefficiencies and higher costs than necessary.

• Takeaway: Right-sizing EC2 instances based on actual workload requirements is crucial. By carefully monitoring resource usage and adjusting instance types to fit the needs of specific workloads, teams can optimize both performance and cost-efficiency.

Mistake #3: Failing to Automate Infrastructure Setup

Lesson Learned: Manual cluster setup may work for small-scale environments but doesn’t scale well in production or larger setups.

• Issue: Teams that started with manual configurations found themselves struggling to maintain consistency across multiple environments, leading to errors and delays during updates.

• Takeaway: Implementing Infrastructure as Code (IaC) through tools like Terraform or AWS CloudFormation is essential for automating cluster creation and management. IaC ensures that clusters are easily reproducible, version-controlled, and aligned with best practices across environments. Additionally, leveraging CI/CD pipelines can significantly streamline the process, making infrastructure setup and deployment more efficient. CI/CD pipelines (such as GitHub Actions) for eks setup can be integrated with IaC to automate not just the deployment of applications but also the provisioning and configuration of your EKS cluster. This ensures that changes are tested, validated, and applied in a consistent manner across environments without manual intervention.

Mistake #4: Underestimating the Upgrade Process

Lesson Learned: Kubernetes upgrades can be tricky, and the process can introduce breaking changes if not managed carefully. Teams often underestimated the complexity of upgrading EKS clusters and suffered downtime or service interruptions as a result.

• Issue: Teams initially skipped upgrade testing, pushing Kubernetes version updates directly to production. This resulted in compatibility issues and disruptions in the production environment.

• Takeaway: Always test upgrades in a staging environment before applying them to production. Key steps include:

  • Check EKS Release Notes: Review the EKS release notes to understand version compatibility and potential breaking changes.
  • Use the EKS Upgrade Checklist: Follow the upgrade checklist in the EKS documentation to ensure all critical steps are covered.
  • Simplify Data Plane Upgrades: Use Managed Node Groups for automated rolling updates or Karpenter for dynamic node provisioning, making node upgrades easier and less error-prone.
  • Backup and Rollback Plan: Always have a backup and rollback plan in case the upgrade doesn’t go as expected.

Mistake #5: Neglecting Security from the Start

Lesson Learned: Security needs to be an integral part of the setup process, not an afterthought. Many teams initially deployed their clusters without properly considering access controls or data protection.

• Issue: Teams often used overly permissive IAM roles and Kubernetes RBAC settings, leading to unnecessary exposure and potential vulnerabilities. Additionally, sensitive data was sometimes stored insecurely, increasing the risk of breaches.

• Takeaway:

  • Limit Permissions: Adopt a least privilege approach for both IAM roles and Kubernetes RBAC. Avoid granting developers cluster-admin permissions. Instead, use tools like RBAC Manager to enforce namespace-specific permissions, ensuring developers have access only to what they need.
  • Protect the API Endpoint: Restrict public access to the EKS API endpoint and configure proper authentication and authorization components to prevent unauthorized users from interacting with the cluster.
  • Secure Sensitive Data: Use secure storage solutions such as external secrets to manage sensitive data, avoiding hardcoding credentials or secrets.

Mistake #6: Overlooking Cost Optimization Opportunities

Lesson Learned: Managing EKS costs efficiently requires a proactive approach. Many teams failed to fully leverage cost-saving tools, leading to unnecessary expenses.

• Issue: Teams often overlooked EC2 Spot Instances for non-production workloads and configured autoscaling inefficiently, resulting in over-provisioned clusters and higher costs.

• Takeaway:

  • Leverage EC2 Spot Instances: Use Spot Instances for workloads that can tolerate interruptions to reduce compute costs.
  • Karpenter: A Game-Changer: Karpenter dynamically provisions and scales nodes based on real-time demand. Unlike traditional autoscalers, it selects the most cost-effective EC2 instances, consolidates workloads efficiently, and reduces waste. This results in significant savings while maintaining performance.
  • Optimize Autoscaling: Combine Karpenter with cluster autoscaling and horizontal pod autoscaling to dynamically adjust resources based on workload demands.

Conclusion

Setting up an EKS cluster is a journey filled with learning opportunities. Through careful planning, automation, and security, organizations can mitigate the risks of missteps that many have encountered. By taking note of these lessons and strategies, teams can avoid common mistakes and build scalable, secure, and cost-effective Kubernetes environments. While the road may not be without its challenges, the lessons learned from others’ experiences can help guide the way toward a more efficient and reliable EKS deployment.