Traefik Forward Auth with Keycloak for SSO
While the Traefik Forward Auth recipe demonstrated a quick way to protect a set of explicitly-specified URLs using OIDC credentials from a Google account, this recipe will illustrate how to use your own Keycloak instance to secure any URLs within your DNS domain.
Keycloak with Traefik
Did you land here from a search, looking for information about using Keycloak with Traefik? All this and more is covered in the Keycloak recipe!
- DNS entry for your auth host ("auth.yourdomain.com" is a good choice), pointed to your keepalived IP
/var/data/config/traefik/traefik-forward-auth.env as per the following example (change "master" if you created a different realm):
CLIENT_ID=<your keycloak client name> CLIENT_SECRET=<your keycloak client secret> OIDC_ISSUER=https://<your keycloak URL>/auth/realms/master SECRET=<a random string to secure your cookie> AUTH_HOST=<the FQDN to use for your auth host> COOKIE_DOMAIN=<the root FQDN of your domain>
Prepare the docker service config
This is a small container, you can simply add the following content to the existing
traefik-app.yml deployed in the previous Traefik recipe:
traefik-forward-auth: image: funkypenguin/traefik-forward-auth env_file: /var/data/config/traefik/traefik-forward-auth.env networks: - traefik_public deploy: labels: - traefik.port=4181 - traefik.frontend.rule=Host:auth.example.com - traefik.frontend.auth.forward.address=http://traefik-forward-auth:4181 - traefik.frontend.auth.forward.trustForwardHeader=true
If you're not confident that forward authentication is working, add a simple "whoami" test container, to help debug traefik forward auth, before attempting to add it to a more complex container.
# This simply validates that traefik forward authentication is working whoami: image: containous/whoami networks: - traefik_public deploy: labels: - traefik.frontend.rule=Host:whoami.example.com - traefik.port=80 - traefik.frontend.auth.forward.address=http://traefik-forward-auth:4181 - traefik.frontend.auth.forward.authResponseHeaders=X-Forwarded-User - traefik.frontend.auth.forward.trustForwardHeader=true
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Redeploy traefik with
docker stack deploy traefik-app -c /var/data/traefik/traeifk-app.yml, to launch the traefik-forward-auth container.
https://whoami.example.com (obviously, customized for your domain and having created a DNS record), and all going according to plan, you'll be redirected to a Keycloak login. Once successfully logged in, you'll be directed to the basic whoami page.
To protect any other service, ensure the service itself is exposed by Traefik (if you were previously using an oauth_proxy for this, you may have to migrate some labels from the oauth_proxy serivce to the service itself). Add the following 3 labels:
- traefik.frontend.auth.forward.address=http://traefik-forward-auth:4181 - traefik.frontend.auth.forward.authResponseHeaders=X-Forwarded-User - traefik.frontend.auth.forward.trustForwardHeader=true
And re-deploy your services :)
What have we achieved? By adding an additional three simple labels to any service, we can secure any service behind our Keycloak OIDC provider, with minimal processing / handling overhead.
- Traefik-forward-auth configured to authenticate against Keycloak
Keycloak vs Authelia
Keycloak is the "big daddy" of self-hosted authentication platforms - it has a beautiful GUI, and a very advanced and mature featureset. Like Authelia, Keycloak can use an LDAP server as a backend, but unlike Authelia, Keycloak allows for 2-way sync between that LDAP backend, meaning Keycloak can be used to create and update the LDAP entries (Authelia's is just a one-way LDAP lookup - you'll need another tool to actually administer your LDAP database).
Chef's notes 📓
Keycloak is very powerful. You can add 2FA and all other clever things outside of the scope of this simple recipe ;) ↩
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