Single log out from Keycloak and OpenShift

OpenShift Security Authentication

- Thomas Jungbauer Thomas Jungbauer ( Lastmod: 2025-05-25 ) - 2 min read

The following 1-minute article is a follow-up to my previous article about how to use Keycloak as an authentication provider for OpenShift. In this article, I will show you how to configure Keycloak and OpenShift for Single Log Out (SLO). This means that when you log out from Keycloak, you will also be logged out from OpenShift automatically. This requires some additional configuration in Keycloak and OpenShift, but it is not too complicated.

Prerequisites

The following prerequisites are required to follow this article:

Keycloak Configuration

Configure the logout URL in Keycloak. This is done by adding a new Valid post logout redirect URIs to the Keycloak client configuration. In this case, we want to call the OpenShift logout URL. Which is: https://oauth-openshift.apps.<your-cluster-name>/logout

This is done in the client settings:

Set Logout URL

OpenShift Configuration

Now we need to configure OpenShift to use the logout URL. This is done by adding a new Post Logout Redirect URI to the OpenShift Console configuration.

Modify the existing Console resource named cluster and add the logoutRedirect parameter to the authentication section. The important pieces of the logout URL are the client_id and the post_logout_redirect_uri. The client ID must be the same as the Keycloak client ID, and the post logout redirect URI must be the OpenShift logout URL. (Also change the <keycloakURL> and <realm> to your Keycloak URL and realm name.)

Actually, instead of client_id, the id_token_hint should be used. But OpenShift does not store the token, so we are using the client ID instead.
apiVersion: config.openshift.io/v1
kind: Console
metadata:
  name: cluster
spec:
  authentication:
    logoutRedirect: 'https://<keycloakURL>/realms/<realm>/protocol/openid-connect/logout?client_id=<realm>&post_logout_redirect_uri=https://console-openshift-console.apps.ocp.aws.ispworld.at' (1)
1The logout URL for OpenShift. This is the URL that will be called when you log out from Keycloak. The URL must contain the client ID and the post logout redirect URI (console of OpenShift).

Wait a few moments until the OpenShift Console Operator applies the new configuration.

Testing the configuration

Now that the configuration is done, we can test the Single Log Out functionality.

  1. We are logged into OpenShift already as user testuser

    Logged in to OpenShift

  2. Now we log out from OpenShift using the Log out button in the upper right corner.

    Log out from OpenShift

  3. This will redirect us to the Keycloak logout page where we need to confirm the logout.

    Keycloak Logout

  4. This will log us out from Keycloak and redirect us back to the OpenShift logout page.

    Logged out from OpenShift

This is it. You are now logged out from both Keycloak and OpenShift. You can also check the Sessions in Keycloak to see that the session for the user is terminated.

Conclusion

As promised, this was a short article about how to configure Keycloak and OpenShift for Single Log Out. This is a beneficial feature if you want to ensure that users are logged out from all applications when they log out from Keycloak. It is also a good security practice to ensure that users are logged out from all applications when they are done using them.

See Also:

  • Step by Step - Using Keycloak Authentication in OpenShift –

    I was recently asked about how to use Keycloak as an authentication provider for OpenShift. How to install Keycloak using the Operator and how to configure Keycloak and OpenShift so that users can log in to OpenShift using OpenID. I have to admit that the exact steps are not easy to find, so I decided to write a blog post about it, describing each step in detail. This time I will not use GitOps, but the OpenShift and Keycloak Web Console to show the steps, because before we put it into GitOps, we need to understand what is actually happening. This article tries to explain every step required so that a user can authenticate to OpenShift using Keycloak as an Identity Provider (IDP) and that Groups from Keycloak are imported into OpenShift. This article does not cover a production grade installation of Keycloak, but only a test installation, so you can see how it works. For production, you might want to consider a proper database (maybe external, but at least with a backup), high availability, etc.).

  • Using ApplicationSet with Matrix Generator and define individual Namespaces –

    During my day-to-day business, I am discussing the following setup with many customers: Configure App-of-Apps. Here I try to explain how I use an ApplicationSet that watches over a folder in Git and automatically adds a new Argo CD Application whenever a new folder is found. This works great, but there is a catch: The ApplicationSet uses the same Namespace default for all Applications. This is not always desired, especially when you have different teams working on different Applications. Recently I was asked by the customer if this can be fixed and if it is possible to define different Namespaces for each Application. The answer is yes, and I would like to show you how to do this.

  • Introducing AdminNetworkPolicies –

    Classic Kubernetes/OpenShift offer a feature called NetworkPolicy that allows users to control the traffic to and from their assigned Namespace. NetworkPolicies are designed to give project owners or tenants the ability to protect their own namespace. Sometimes, however, I worked with customers where the cluster administrators or a dedicated (network) team need to enforce these policies. Since the NetworkPolicy API is namespace-scoped, it is not possible to enforce policies across namespaces. The only solution was to create custom (project) admin and edit roles, and remove the ability of creating, modifying or deleting NetworkPolicy objects. Technically, this is possible and easily done. But shifts the whole network security to cluster administrators. Luckily, this is where AdminNetworkPolicy (ANP) and BaselineAdminNetworkPolicy (BANP) comes into play.

  • Using Kustomize to post render a Helm Chart –

    Lately I came across several issues where a given Helm Chart must be modified after it has been rendered by Argo CD. Argo CD does a helm template to render a Chart. Sometimes, especially when you work with Subcharts or when a specific setting is not yet supported by the Chart, you need to modify it later …​ you need to post-render the Chart. In this very short article, I would like to demonstrate this on a real-live example I had to do. I would like to inject annotations to a Route objects, so that the certificate can be injected. This is done by the cert-utils operator. For the post-rendering the Argo CD repo pod will be extended with a sidecar container, that is watching for the repos and patches them if required.

  • Managing Certificates using GitOps approach –

    The article SSL Certificate Management for OpenShift on AWS explains how to use the Cert-Manager Operator to request and install a new SSL Certificate. This time, I would like to leverage the GitOps approach using the Helm Chart cert-manager I have prepared to deploy the Operator and order new Certificates. I will use an ACME Letsencrypt issuer with a DNS challenge. My domain is hosted at AWS Route 53. However, any other integration can be easily used.

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