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ALB Controller

In this lab, we'll explore common issues that can occur when working with Amazon EKS and learn effective troubleshooting techniques. We'll work through real-world scenarios focusing on the AWS Load Balancer Controller and service connectivity problems. If you'd like to learn more about how a Load balancer controller work, check out the Fundamentals module or AWS LB Controller official documentation for more information.

Before you start

Prepare your environment for this section:

~$prepare-environment troubleshooting/alb
You can view the Terraform that applies these changes here.


info
The preparation of the lab might take a couple of minutes and it will make the following changes to your lab environment:
    

  • Deploy a sample UI application
    • 

  • Configure an ingress resource
    • 

  • Set up initial AWS Load Balancer Controller configuration (with deliberate issues for troubleshooting)
    • 

  • Create necessary IAM roles and policies
    • 



Environment Setup Details​


The prepare-environment script has created several resources with specific issues that we'll troubleshoot:


    

  • A UI application deployment in the ui namespace
    • 

  • An ingress resource configured to use the AWS Load Balancer Controller
    • 

  • IAM roles and policies (with intentional misconfigurations)
    • 

  • Kubernetes service resources
    • 



These components have been configured with common real-world issues that we'll identify and fix throughout this module.


What We'll Cover​


We'll troubleshoot several issues including:


    

  • Missing or incorrect subnet tags preventing ALB creation
    • 

  • IAM permission issues blocking the Load Balancer Controller
    • 

  • Service selector misconfigurations
    • 

  • Ingress backend service problems
    • 



Prerequisites​


Before proceeding, ensure you have:


    

  • Access to the EKS cluster
    • 

  • Proper AWS CLI configuration
    • 

  • kubectl installed and configured
-Basic understanding of Kubernetes networking concepts
    • 



Tools We'll Use​


Throughout this module, we'll use these troubleshooting tools:


    

  • kubectl commands for Kubernetes resource inspection
    • 

  • AWS CLI for checking AWS resource states
    • 

  • CloudWatch Logs for controller diagnostics
    • 

  • AWS IAM tools for permission verification
    • 



Before you proceed
After a couple minutes from running the prepare-environment script, verify the service and ingress is up and running.
~$kubectl get svc -n ui
NAME   TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
ui     ClusterIP   172.20.224.112   <none>        80/TCP    12d
~$kubectl get ingress -n ui
NAME   CLASS   HOSTS   ADDRESS   PORTS   AGE
ui     alb     *                 80      11m
 
Let's verify the load balancer was indeed not created:
~$aws elbv2 describe-load-balancers --query 'LoadBalancers[?contains(LoadBalancerName, `k8s-ui-ui`) == `true`]'
[]


Let's begin by investigating why our Application Load Balancer isn't being created!