Скачать или смотреть How to Use Kubernetes Nginx-ingress as a Load Balancer for External Services

Discover how to configure the `nginx-ingress controller` in Kubernetes to connect your services to external backends, effectively acting as a load balancer.
---
This video is based on the question https://stackoverflow.com/q/63594846/ asked by the user 'jj2424' ( https://stackoverflow.com/u/14169094/ ) and on the answer https://stackoverflow.com/a/63723245/ provided by the user 'Justin Tamblyn' ( https://stackoverflow.com/u/3932734/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: K8s service LB to external services w/ nginx-ingress controller

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Configuring Kubernetes Nginx-ingress as a Load Balancer for External Services

Kubernetes (K8s) provides a robust framework for managing containerized applications, but you may encounter scenarios where your applications need to connect with external services. An interesting question arises: Can we configure the K8s nginx-ingress controller to act as a load balancer (LB) that connects a Kubernetes service to external backends hosted on external hosts and ports? This guide will explore this problem and provide a step-by-step guide on how to set this up effectively.

Understanding the Problem

Typically, Kubernetes services are designed to load balance traffic coming from external clients to pods within the cluster. The usual flow is as follows:

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

However, in certain cases, you may want the flow to be like this instead:

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

The goal here is to configure the nginx-ingress controller in such a way that it can direct traffic from a service to an external backend server. This can be particularly useful in on-premise settings where direct connections to external services are necessary.

Step-by-Step Solution

To set up the nginx-ingress controller as described, follow these steps:

1. Define a Kubernetes Service

Instead of using a selector, we will create a service that does not select pods directly. Here’s how to define it:

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

2. Create Endpoints

Since the service doesn't have a selector, we need to manually define the Endpoints that specify the external IPs and ports that the service needs to connect to. Here’s an example of how to define them:

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

3. Configure the Ingress Resource

Finally, we need to configure the Ingress resource to route traffic to the defined service. Here’s an example configuration for the ingress resource:

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

Key Points to Remember

Endpoints are essential: When you create a service without a selector, you must define an endpoints resource for that service to facilitate proper routing.

Nginx-ingress annotations: Be sure to properly annotate your ingress to ensure that it uses the nginx ingress controller.

Networking considerations: Ensure that external services can accept incoming connections from your Kubernetes nodes.

Conclusion

By following the steps outlined above, you can configure the Kubernetes nginx-ingress controller to act as a load balancer that routes traffic from internal services to external backends. This setup provides flexibility in how your applications communicate with services outside of the Kubernetes cluster and harnesses the power of Nginx for handling HTTP requests effectively.

This configuration allows for a seamless integration with external systems while maintaining the strengths of Kubernetes services and ingress resources. Implementing this will enable your team to run efficient, well-structured applications that can easily communicate with necessary external dependencies.