Скачать или смотреть Why Your Azure Kubernetes Load Balancer Isn't Working and How to Fix It

Discover common issues with `Azure Kubernetes Load Balancer` and learn how to troubleshoot and resolve them for optimal performance.
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Troubleshooting Azure Kubernetes Load Balancer Issues

When deploying applications to Azure Kubernetes Service (AKS), sometimes you might encounter issues such as your web pages not loading despite setting up a Load Balancer. This can be frustrating, especially when you have followed the deployment steps correctly. In this guide, we'll explore why your Azure Kubernetes Load Balancer isn't functioning as expected and guide you through the troubleshooting process.

Understanding the Problem

Imagine you've deployed NGINX demo containers and configured a Load Balancer in Azure; however, when you try to access the service, the web page fails to load. This situation can arise from misconfigured network security groups (NSGs), incorrect service types, or simply accessing the wrong port.

The Setup

You may have run the following commands to deploy your application:

[[See Video to Reveal this Text or Code Snippet]]

After exposing your application, you check the service status with:

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You should see output similar to:

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However, when trying to access your app via curl http://20.25.212.62:31162, nothing loads. So, what could be the issue?

Analyzing the Issue

The main issue here is likely related to the port you are trying to access. When you create a Kubernetes service of type LoadBalancer, it exposes a network service using a Node port. This Node port is not necessarily the same as the port you used to expose your application.

Key Points to Note

LoadBalancer Behavior: By default, a LoadBalancer service uses a Node port to route external traffic to your application.

Node Port Access: Requests sent to the Load Balancer's external IP are forwarded to one of your cluster nodes via the node port.

Example Scenario

Assuming you have two nodes in your AKS cluster (let's say node1 and node2), when you send a request like:

[[See Video to Reveal this Text or Code Snippet]]

This will forward the request to either node1:nodeport or node2:nodeport, depending on how the Load Balancer routes it.

The Solution: Accessing the Correct Port

To successfully access your application, ensure you're using the external IP without the node port. Here’s what you need to try:

Use the base IP for the initial request:

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Or specify port 80 explicitly if needed:

[[See Video to Reveal this Text or Code Snippet]]

Verifying Network Security Group (NSG) Configuration

If you still cannot access the application, double-check your Azure Network Security Group (NSG) settings. Ensure that:

The NSG is correctly configured to allow inbound traffic on port 80 (or any specified port).

There are no rules that block the traffic from reaching your Load Balancer.

Conclusion

Getting your Azure Kubernetes Load Balancer to work smoothly can sometimes involve minor tweaks. The common oversight of accessing the wrong port or forgetting about NSG configurations can lead to frustrating scenarios where your application remains inaccessible.

By understanding how Load Balancers, Node ports, and security settings work together, you can rapidly diagnose issues and get your applications running in no time.

We hope this guide helps you troubleshoot and successfully run your applications on Azure Kubernetes Service. Happy coding!