Configuring Keycloak (SAML)

If your organization uses Keycloak Identity Provider (IdP) for user authentication, you can configure Rancher to allow your users to log in using their IdP credentials.

Prerequisites

• You must have a Keycloak IdP Server configured.

• In Keycloak, create a new SAML client, with the settings below. See the Keycloak documentation for help.

  Setting	Value
  Sign Documents	ON 1
  Sign Assertions	ON 1
  All other ON/OFF Settings	OFF
  Client ID	Either https://yourRancherHostURL/v1-saml/keycloak/saml/metadata or the value configured in the Entry ID Field of the Rancher Keycloak configuration2
  Client Name	(e.g. rancher)
  Client Protocol	SAML
  Valid Redirect URI	https://yourRancherHostURL/v1-saml/keycloak/saml/acs

  1: Optionally, you can enable either one or both of these settings. 2: Rancher SAML metadata won’t be generated until a SAML provider is configured and saved.

• In the new SAML client, create Mappers to expose the users fields

  • Add all “Builtin Protocol Mappers”
  • Create a new “Group list” mapper to map the member attribute to a user’s groups

• Export a metadata.xml file from your Keycloak client: From the Installation tab, choose the SAML Metadata IDPSSODescriptor format option and download your file.

Note Keycloak versions 6.0.0 and up no longer provide the IDP metadata under the Installation tab. You can still get the XML from the following url:

https://{KEYCLOAK-URL}/auth/realms/{REALM-NAME}/protocol/saml/descriptor

The XML obtained from this URL contains EntitiesDescriptor as the root element. Rancher expects the root element to be EntityDescriptor rather than EntitiesDescriptor. So before passing this XML to Rancher, follow these steps to adjust it:

• Copy all the attributes from EntitiesDescriptor to the EntityDescriptor that are not present.
• Remove the <EntitiesDescriptor> tag from the beginning.
• Remove the </EntitiesDescriptor> from the end of the xml.

You are left with something similar as the example below:

<EntityDescriptor xmlns="urn:oasis:names:tc:SAML:2.0:metadata" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" entityID="https://{KEYCLOAK-URL}/auth/realms/{REALM-NAME}">
  .... 
</EntityDescriptor>

Configuring Keycloak in Rancher

1. In the top left corner, click ☰ > Users & Authentication.
2. In the left navigation menu, click Auth Provider.
3. Click Keycloak SAML.
4. Complete the Configure Keycloak Account form. For help with filling the form, see the configuration reference.

5. After you complete the Configure a Keycloak Account form, click Enable.

   Rancher redirects you to the IdP login page. Enter credentials that authenticate with Keycloak IdP to validate your Rancher Keycloak configuration.

   Note: You may have to disable your popup blocker to see the IdP login page.

Result: Rancher is configured to work with Keycloak. Your users can now sign into Rancher using their Keycloak logins.

SAML Provider Caveats:

• SAML Protocol does not support search or lookup for users or groups. Therefore, there is no validation on users or groups when adding them to Rancher.
• When adding users, the exact user IDs (i.e. UID Field) must be entered correctly. As you type the user ID, there will be no search for other user IDs that may match.

• When adding groups, you must select the group from the drop-down that is next to the text box. Rancher assumes that any input from the text box is a user.

  • The group drop-down shows only the groups that you are a member of. You will not be able to add groups that you are not a member of.

Configuration Reference

Tip: You can generate a key/certificate pair using an openssl command. For example:

   openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout myservice.key -out myservice.cert

Annex: Troubleshooting

If you are experiencing issues while testing the connection to the Keycloak server, first double-check the configuration option of your SAML client. You may also inspect the Rancher logs to help pinpointing the problem cause. Debug logs may contain more detailed information about the error. Please refer to How can I enable debug logging in this documentation.

You are not redirected to Keycloak

When you click on Authenticate with Keycloak, you are not redirected to your IdP.

• Verify your Keycloak client configuration.
• Make sure Force Post Binding set to OFF.

Forbidden message displayed after IdP login

You are correctly redirected to your IdP login page and you are able to enter your credentials, however you get a Forbidden message afterwards.

• Check the Rancher debug log.
• If the log displays ERROR: either the Response or Assertion must be signed, make sure either Sign Documents or Sign assertions is set to ON in your Keycloak client.

HTTP 502 when trying to access /v1-saml/keycloak/saml/metadata

This is usually due to the metadata not being created until a SAML provider is configured. Try configuring and saving keycloak as your SAML provider and then accessing the metadata.

Keycloak Error: “We’re sorry, failed to process response”

• Check your Keycloak log.
• If the log displays failed: org.keycloak.common.VerificationException: Client does not have a public key, set Encrypt Assertions to OFF in your Keycloak client.

Keycloak Error: “We’re sorry, invalid requester”

• Check your Keycloak log.
• If the log displays request validation failed: org.keycloak.common.VerificationException: SigAlg was null, set Client Signature Required to OFF in your Keycloak client.