Rancher-SAML-ADFS (Authentik)

What is Rancher​

An enterprise platform for managing Kubernetes Everywhere Rancher is a platform built to address the needs of the DevOps teams deploying applications with Kubernetes, and the IT staff responsible for delivering an enterprise-critical service.

-- https://rancher.com/products/rancher

Preparation​

The following placeholders will be used:

• rancher.company is the FQDN of the Rancher install.
• authentik.company is the FQDN of the authentik install.

Under Customization -> Property Mappings, create a SAML Property Mapping. Give it a name like "SAML Rancher User ID". Set the SAML name to rancherUidUsername and the expression to the following

return f"{user.pk}-{user.username}"

Create an application in authentik. Set the Launch URL to https://rancher.company, as Rancher does not currently support IdP-initiated logins.

Create a SAML provider with the following parameters:

• ACS URL: https://rancher.company/v1-saml/adfs/saml/acs
• Audience: https://rancher.company/v1-saml/adfs/saml/metadata
• Issuer: authentik
• Service Provider Binding: Post
• Property mappings: Select all default mappings and the mapping you've created above.
• Signing Certificate: Select the authentik self-signed certificate.

You can of course use a custom signing certificate, and adjust durations.

Rancher​

In Rancher, navigate to Global -> Security -> Authentication, and select ADFS.

Fill in the fields

• Display Name Field: http://schemas.xmlsoap.org/ws/2005/05/identity/claims/name
• User Name Field: http://schemas.goauthentik.io/2021/02/saml/username
• UID Field: rancherUidUsername
• Groups Field: http://schemas.xmlsoap.org/claims/Group

For the private key and certificate, you can either generate a new pair (in authentik, navigate to Identity & Cryptography -> Certificates and select Generate), or use an existing pair.

Copy the metadata from authentik, and paste it in the metadata field.

Click on save to test the authentication.