Скачать или смотреть Troubleshooting Backchannel Connection Issues in Keycloak 20.0.2

Discover how to resolve backchannel connection issues in Keycloak 20.0.2 with this comprehensive troubleshooting guide.
---
This video is based on the question https://stackoverflow.com/q/75327787/ asked by the user 'Tamaki Sakura' ( https://stackoverflow.com/u/3608412/ ) and on the answer https://stackoverflow.com/a/75330723/ provided by the user 'Tamaki Sakura' ( https://stackoverflow.com/u/3608412/ ) 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: Keycloak 20.0.2 does not accept backchannel connection

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.
---
Troubleshooting Backchannel Connection Issues in Keycloak 20.0.2

When working with authentication systems like Keycloak, encountering connection issues can be frustrating, particularly when it comes to integrating Keycloak with web applications. A common problem that users face is the inability to establish a backchannel connection, which can prevent backend services from authenticating properly. In this guide, we will explore a specific issue encountered with Keycloak version 20.0.2, where backend login attempts fail and return a 401 error, while frontend interactions remain operational.

Understanding the Problem

In the scenario we are discussing, a user reported successful frontend logins with Keycloak but faced issues when attempting to authenticate via the backend service. The backend service utilizes HAProxy as a reverse proxy to connect to Keycloak's internal address. Although the frontend Keycloak control console is accessible without issues, backend API calls result in a 401 Unauthorized error when using the internal Keycloak URL.

Here’s a breakdown of the URLs being accessed:

Public Keycloak URL: https://example.com/white-graduation/...

Internal Keycloak URL: http://loginservice:8080/white-graduation/keycloak/auth

After performing tests using curl commands, it was confirmed that while accessing the public Keycloak URL via a valid bearer token returned a 200 status code, the same API call made directly to the internal Keycloak URL returned a 401 status code. This indicates a problem with the backchannel communication.

Initial Configuration Review

The initial configuration provided by the user is critical in diagnosing this issue. Here are the key elements:

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

KC_HTTP_RELATIVE_PATH: Configured properly for the application's routing.

KC_HOSTNAME_ADMIN_URL: Points to the public-facing Keycloak URL.

KC_PROXY: Set to edge, which can influence how clients interact with Keycloak.

Notably, the user did not set KC_HOSTNAME_STRICT_BACKCHANNEL, which defaults to false, indicating that backchannel connections should work by default.

The Solution

After seeking further clarity on this issue, the solution was found by adding the following environment variable configuration:

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

This adjustment ensures that KC_HOSTNAME_URL matches KC_HOSTNAME_ADMIN_URL. Once this configuration change was implemented, the backend API connections began functioning correctly without returning a 401 error.

Why This Works

While the user was unsure why this particular setting resolved the issue, it can be inferred that ensuring consistency in the hostname configuration allows Keycloak to correctly validate and process requests both from the public and internal environment. Here are some takeaways regarding the configuration setup:

Consistency is Key: Ensure that the public and internal URLs are in sync concerning how Keycloak identifies itself to clients.

Testing Environment: The settings applied were suitable for a non-production environment, which often requires different configurations than a live production setup.

Conclusion

The resolution of the backchannel connection issue in Keycloak 20.0.2 underscores the importance of comprehensive configuration alignment when dealing with service integrations. By ensuring that the public and internal URLs match, users can facilitate smoother authentication flows and overcome common pitfalls. While the recommended settings for production may vary, the solution provided here effectively addresses the problem at hand.

By following this guide, you should be equipped to tackle similar issues within your own Keycloak setups. Happy coding!