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Integrate with Atlantis

Support level: Community

What is Atlantis?​

Atlantis is an application for automating Terraform via pull requests.

-- https://www.runatlantis.io

Atlantis does not provide native SSO for the web UI. Use authentik as a forward auth proxy in front of Atlantis, and allow the Atlantis webhook endpoint to remain reachable by your Git host.

Preparation​

The following placeholders are used in this guide:

  • atlantis.company is the FQDN of the Atlantis installation.
  • authentik.company is the FQDN of the authentik installation.
info

This documentation lists only the settings that you need to change from their default values. Be aware that any changes other than those explicitly mentioned in this guide could cause issues accessing your application.

authentik configuration​

To support the integration of Atlantis with authentik, you need to create an application/provider pair in authentik. This guide assumes that Atlantis is already deployed behind a reverse proxy that supports authentik forward auth.

Create an application and provider in authentik​

  1. Log in to authentik as an administrator and open the authentik Admin interface.

  2. Navigate to Applications > Applications and click New Application to open the application wizard.

    • Application: provide a descriptive name, an optional group for the type of application, the policy engine mode, and optional UI settings.

    • Choose a Provider type: select Proxy Provider as the provider type.

    • Configure the Provider: provide a name (or accept the auto-provided name), the authorization flow to use for this provider, and the following required configurations.

      • Set Mode to Forward auth (single application).

      • Set External host to https://atlantis.company.

      • Under Advanced protocol settings, set Unauthenticated Paths to the following value:

        ^/events$

      • Under Authentication settings, disable Intercept header authentication.

    • Configure Bindings (optional): you can create a binding (policy, group, or user) to manage the listing and access to applications on a user's Application Dashboard page.

  3. Click Submit to save the new application and provider.

Configure proxy outpost​

The proxy provider requires an authentik proxy outpost. If you do not already have a proxy outpost, follow the outpost documentation to create and deploy one.

Add the Atlantis application to a proxy outpost that will serve it:

  1. Log in to authentik as an administrator and open the authentik Admin interface.
  2. Navigate to Applications > Outposts.
  3. Click the edit icon for the proxy outpost. This can be the built-in authentik Embedded Outpost or another proxy outpost.
  4. Under Available Applications, select the Atlantis application and move it to Selected Applications.
  5. Click Update to save your changes.

Atlantis configuration​

No SSO configuration is required in Atlantis.

Configure your reverse proxy to use the authentik outpost as the forward auth endpoint for https://atlantis.company.

Requests to /outpost.goauthentik.io must be routed to the authentik outpost. All other requests, including /events, must continue to be routed to Atlantis.

Set your Git host webhook URL to https://atlantis.company/events. The /events endpoint is skipped by authentik so that Git host webhooks can reach Atlantis. Atlantis should still validate those webhook requests with its existing webhook secret or webhook authentication settings.

Configuration verification​

To verify the login flow, open Atlantis. You should be redirected to authentik before the Atlantis web interface is shown.

Resources​