Source URL: https://glasskube.dev/blog/kubernetes-zero-downtime-deployments-aws-eks/
Source: Hacker News
Title: Zero-Downtime Kubernetes Deployments on AWS with EKS
Feedly Summary: Comments
AI Summary and Description: Yes
Summary: This blog post discusses the intricacies of achieving zero-downtime deployments on AWS EKS, particularly focusing on the AWS Load Balancer Controller. The author shares practical solutions for dealing with downtime during application updates by utilizing Kubernetes features such as Pod Readiness Gates and implementing graceful shutdowns paired with termination delays. This content is especially relevant for engineers, DevOps, and cloud infrastructure professionals seeking to enhance their application deployment strategies.
Detailed Description:
The article provides a comprehensive guide on how to minimize downtime during application updates deployed on AWS EKS, specifically when using the AWS Load Balancer Controller for managing routing. The following key points are discussed:
– **Understanding AWS Load Balancer Controller**:
– The controller is essential for mapping Ingress resources to AWS Application Load Balancers & LoadBalancer services to AWS Network Load Balancers.
– The delay in IP address updates in the target group can contribute to downtimes.
– **Common Downtime Issues**:
– The system’s health checks can lead to all pods being marked unhealthy if they are replaced too rapidly.
– Requests can be routed to pods that have already been terminated, resulting in HTTP 502 and 504 errors.
– **Solution Strategies**:
– **Pod Readiness Gates**: By implementing readiness gates, Kubernetes can wait until the new pod is fully ready before scaling down the old replica set, thus minimizing downtime.
– Implementation involves labeling the namespace with `elbv2.k8s.aws/pod-readiness-gate-inject=enabled`.
– **Graceful Application Shutdown**: Implementing a graceful shutdown process in application code can prevent immediate termination on receiving a shutdown signal.
– Illustrated with Go programming, emphasizing proper handling of termination signals and ensuring ongoing requests are completed before shutting down.
– **Kubernetes Termination Delay with Sidecars**: This method can help manage the time taken during pod shutdown gracefully, although challenges arise with distroless images.
– Suggested to either incorporate delay handling directly in the application code or utilize preStop lifecycle hooks for standard images.
– **Outcome and Conclusion**:
– By applying these solutions, the author successfully achieves zero-downtime deployments.
– The article also emphasizes the importance of understanding the underlying mechanics of external load balancers and Kubernetes components to effectively manage deployments.
Overall, the content serves as a valuable learning resource for security and compliance professionals interested in ensuring the reliability and stability of application deployments in cloud environments. Understanding these practices enhances security through robust operational processes and mitigates risks associated with downtime during updates.