Authentik

Authentik is a single sign-on (SSO) tool that allows you to log in once to all platforms compatible with OpenID. It can also secure access to your exposed services by injecting itself via SWAG into requests to those services.

For example, if you're exposing Dockge online at dockge.mydomain.com, you’ll first land on an Authentik login page when accessing it. If you've already authenticated with another Authentik-protected service, you won’t need to log in again. This allows you to authenticate only once per day for all protected services.

Authentik also supports multi-factor authentication, including TOTP (a code generated by the authentication app of your choice). Additionally, it allows login through Microsoft or Google accounts, provided you've configured one of those applications.

It's a great alternative to VPNs for securely exposing services, especially ones that lack MFA or login protection (e.g., the SWAG dashboard).

Authentik has extensive documentation and great tutorials from Cooptonian. Here, we’ll cover the basics using Dockge as an example.

There are two main modes you should know:

• The first allows apps with native support for OpenID-compatible SSO to connect directly to Authentik. This is the preferred method, as the app itself decides what’s public and what’s protected.

• The second method injects Authentik authentication through SWAG before reaching the target service.

Both modes can be configured on a per-application basis.

Installation

Folder structure:

root
└── docker
    └── authentik
        ├── .env
        ├── compose.yml
        ├── media
        ├── certs
        ├── custom-template
        └── ssh

Create the folders:

sudo mkdir -p /docker/authentik/media /docker/authentik/certs /docker/authentik/custom-template /docker/authentik/ssh

Navigate to the authentik folder and generate a password and secret key to include in the .env file:

sudo echo "PG_PASS=$(openssl rand 36 | base64)" >> .env
sudo echo "AUTHENTIK_SECRET_KEY=$(openssl rand 60 | base64)" >> .env

sudo vi /docker/authentik/compose.yml

Open Dockge and search for "authentik" in the inactive stacks. Name the stack authentik and paste the following configuration, replacing {AUTHENTIK_TAG:-2024.2.3} with the latest version of Authentik.

---
services:

  postgresql:
    image: docker.io/library/postgres:12-alpine
    container_name: authentik-postgresql
    restart: unless-stopped
    healthcheck:
      test:
        - CMD-SHELL
        - pg_isready -d $${POSTGRES_DB} -U $${POSTGRES_USER}
      start_period: 20s
      interval: 30s
      retries: 5
      timeout: 5s
    volumes:
      - database:/var/lib/postgresql/data
    environment:
      POSTGRES_PASSWORD: ${PG_PASS:?database password required}
      POSTGRES_USER: ${PG_USER:-authentik}
      POSTGRES_DB: ${PG_DB:-authentik}
    env_file:
      - .env

  redis:
    image: docker.io/library/redis:alpine
    container_name: authentik-redis
    command: --save 60 1 --loglevel warning
    restart: unless-stopped
    healthcheck:
      test:
        - CMD-SHELL
        - redis-cli ping | grep PONG
      start_period: 20s
      interval: 30s
      retries: 5
      timeout: 3s
    volumes:
      - redis:/data
  
  server:
    image: ${AUTHENTIK_IMAGE:-ghcr.io/goauthentik/server}:${AUTHENTIK_TAG:-2024.2.3}
    container_name: authentik-server
    restart: unless-stopped
    command: server
    environment:
      AUTHENTIK_REDIS__HOST: redis
      AUTHENTIK_POSTGRESQL__HOST: postgresql
      AUTHENTIK_POSTGRESQL__USER: ${PG_USER:-authentik}
      AUTHENTIK_POSTGRESQL__NAME: ${PG_DB:-authentik}
      AUTHENTIK_POSTGRESQL__PASSWORD: ${PG_PASS}
    volumes:
      - ./media:/media
      - ./custom-templates:/templates
      - ./auth.css:/web/dist/custom.css
      - ./ssh:/authentik/.ssh
    env_file:
      - .env
    ports:
      - ${COMPOSE_PORT_HTTP:-9000}:9000
      - ${COMPOSE_PORT_HTTPS:-9443}:9443
    depends_on:
      - postgresql
      - redis

  worker:
    image: ${AUTHENTIK_IMAGE:-ghcr.io/goauthentik/server}:${AUTHENTIK_TAG:-2024.2.3}
    container_name: authentik-worker
    restart: unless-stopped
    command: worker
    environment:
      AUTHENTIK_REDIS__HOST: redis
      AUTHENTIK_POSTGRESQL__HOST: postgresql
      AUTHENTIK_POSTGRESQL__USER: ${PG_USER:-authentik}
      AUTHENTIK_POSTGRESQL__NAME: ${PG_DB:-authentik}
      AUTHENTIK_POSTGRESQL__PASSWORD: ${PG_PASS}
    # `user: root` and the docker socket volume are optional.
    # See more for the docker socket integration here:
    # https://goauthentik.io/docs/outposts/integrations/docker
    # Removing `user: root` also prevents the worker from fixing the permissions
    # on the mounted folders, so when removing this make sure the folders have the correct UID/GID
    # (1000:1000 by default)
    user: root
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - ./media:/media
      - ./certs:/certs
      - ./custom-templates:/templates
      - ./auth.css:/web/dist/custom.css
      - ./ssh:/authentik/.ssh
    env_file:
      - .env
    depends_on:
      - postgresql
      - redis

volumes:
  database:
    driver: local
  redis:
    driver: local

In the .env file, the PG_PASS and AUTHENTIK_SECRET_KEY variables are already set. Deploy the stack.

You can then begin the initial setup by visiting:
http://yourserverip:9000/if/flow/initial-setup/

Exposing Authentik

To use Authentik outside your local network, you must expose it.

Open the authentik-server.conf file:

sudo vi /docker/swag/config/nginx/authentik-server.conf

Verify that the following variables are set correctly:

set $upstream_authentik authentik-server;
proxy_pass http://$upstream_authentik:9000;

If not, press i to enter edit mode, make the necessary changes, then save and exit by pressing Esc followed by :x.

Create the auth.subdomain.conf file:

sudo vi /docker/swag/config/nginx/proxy-confs/auth.subdomain.conf

Press i to enter edit mode and paste the following configuration:

## Version 2023/05/31
# Ensure your authentik container is named authentik-server
# Ensure your DNS has a CNAME for authentik

server {
    listen 443 ssl;
    listen [::]:443 ssl;

    server_name auth.*;

    include /config/nginx/ssl.conf;

    client_max_body_size 0;

    location / {
        include /config/nginx/proxy.conf;
        include /config/nginx/resolver.conf;
        set $upstream_app authentik-server;
        set $upstream_port 9000;
        set $upstream_proto http;
        proxy_pass $upstream_proto://$upstream_app:$upstream_port;
    }

    location ~ (/authentik)?/api {
        include /config/nginx/proxy.conf;
        include /config/nginx/resolver.conf;
        set $upstream_app authentik-server;
        set $upstream_port 9000;
        set $upstream_proto http;
        proxy_pass $upstream_proto://$upstream_app:$upstream_port;
    }
}

Save and exit by pressing Esc then :x.

Go to Dockge, and edit the SWAG compose file to add the Authentik network:

services:
  swag:
     container_name: # ...
      # ...
     networks:               # Attach the container to the custom network
      # ...           
      - authentik            # Name of the network declared in the stack

networks:                    # Define the custom network
  # ...
  authentik:                 # Name of the network declared in the stack
    name: authentik_default  # Actual name of the external network
    external: true           # Indicates it's an external network

Restart the stack and wait for SWAG to be fully operational.

Done! You can now access Authentik via https://auth.mydomain.com

Enable Multifactor Authentication

The main value of Authentik is using multifactor authentication for all protected apps.

• Go to https://auth.mydomain.com
• Log in
• Go to Settings
• Click the MFA section
• Click Register
• Choose a method like TOTP device (you'll need an authenticator app like Google Authenticator)
• Follow the steps

You’ll now be prompted to enter a one-time code at every login.

Protecting a Native App

Authentik is natively compatible with several applications. You can find the list and support here.

Protecting an App via Reverse Proxy

SWAG lets you insert Authentik’s login page between a request and access to your service. To do this:

• Configure the authentication provider in Authentik.
• Edit the domain proxy file so SWAG can intercept the request.

Why do this when Dockge already has authentication? Because Dockge uses weak HTTP authentication. With Authentik, you get strong MFA authentication and automatic login to all apps protected by Authentik. This secures access to Dockge and other apps without needing a VPN.

Configuring Authentik

• Go to Authentik
• Open the admin panel
• Select Applications then Create with wizard
• Fill in the fields as shown:

• At the next step, choose "Forward authentication (single application)" and configure it as shown (flows are important):

• Next, go to the Outposts menu on the left and edit authentik Embedded Outpost:

• Add the dockge application by moving it to the right column and save.

Configuring SWAG

Edit the file dockge.mydomain.com:

sudo vi /docker/swag/config/nginx/proxy-confs/dockge.subdomain.conf

Press i to enter edit mode and uncomment the two lines #include /config/nginx/authentik-server.conf;

Press Esc, type :x, and press Enter to save and exit.

Done! Now when accessing https://dockge.mydomain.com, you’ll be redirected to the Authentik login screen.

Your new architecture looks like this:

Protecting a Remote Server Service

For a native application (via OAuth 2.0 or other), nothing changes.

For a non-native app behind a reverse proxy, you must deploy an Outpost. An Outpost is a container acting as a local proxy — it's the target of your app's auth requests and the only one authorized to communicate with your Authentik API.

This container will forward requests to your main Authentik instance over the internet (or your local network). The server will perform checks and respond to the Outpost, which will allow or block access accordingly.

Configuring Authentik

Create your providers and applications as shown earlier.

Then, in the admin panel, go to Applications > Outposts, and create a new outpost.

Fill in as follows:

In the Advanced settings section, clear the existing content and enter:

log_level: info
docker_labels: null
authentik_host: https://your_authentik_server_domain/
object_naming_template: ak-outpost-%(name)s
authentik_host_insecure: false
container_image:
docker_network: null
docker_map_ports: true
docker_labels: null

Save and exit.

On the list of created outposts, locate the new one and click Show details at the end of the line. Carefully copy the access token.

Configuring the Remote Machine

We assume you’ve already installed Docker and SWAG on this remote machine.

On your remote machine, use Dockge to create a stack named authentik-outpost.

If you haven’t installed Dockge, create a folder /docker/authentik-outpost, or directly via command line:

sudo mkdir -P /docker/authentik-outpost

Create the compose.yaml file or paste the configuration directly into Dockge if installed.

Via command line:

sudo vi /docker/authentik-outpost/compose.yaml

Enter edit mode by pressing i and paste the following configuration, updating the version in {AUTHENTIK_TAG:proxy:2024.2.3} to match your Authentik server version.

version: "3.5"
services:
  authentik_proxy:
    container_name: authentik-outpost
    image: ghcr.io/goauthentik/proxy:2024.2.3
    # Optionally specify which networks the container should be
    # might be needed to reach the core authentik server
    restart: unless-stopped
    env_file:
      - .env
    ports:
      - 9000:9000
      - 9443:9443
    environment:
      AUTHENTIK_HOST: ${HOST}
      AUTHENTIK_INSECURE: "false"
      AUTHENTIK_TOKEN: ${TOKEN}

Go to the SWAG stack on the remote machine (or edit directly using Dockge) and add the authentik-outpost network in the configuration file like this (see networks section):

sudo vi /docker/swag/compose.yaml

services:
  swag:
     container_name: #...
      # ... 
     networks:                      # Attach the container to the custom network
      - authentik-outpost           # Network name as declared in the stack

networks:                           # Define the custom network
  #...
  authentik-outpost:                # Name of the network declared in the stack
    name: authentik-outpost_default # Actual name of the external network
    external: true                  # Marks it as an external network

Press Esc, then type :x and press Enter to save and exit.

If using Dockge, restart SWAG.

Otherwise, via terminal:

cd /docker/swag/
sudo docker compose up -d

Create (or fill using Dockge) the .env file in the authentik-outpost directory:

Via command line:

sudo vi /docker/authentik-outpost/.env

Enter edit mode with i and paste the following configuration:

HOST=
TOKEN=

Fill in the values:

Press Esc, then type :x and press Enter to save and exit.

If using Dockge, deploy the stack.

Otherwise, via terminal:

cd /docker/authentik-outpost/
sudo docker compose up -d

The container is now running. You can verify its status from your Authentik instance admin panel under Applications > Outposts.

Now, let’s configure SWAG.

Open the authentik-server.conf file:

sudo vi /docker/swag/config/nginx/authentik-server.conf

In the file, press i to enter edit mode and change authentik-server to authentik-outpost as shown:

set $upstream_authentik authentik-outpost;
proxy_pass http://$upstream_authentik:9000;

Save and exit with Esc, then :x and Enter.

Then configure the applications to protect as you did on your main server, whether they are native or protected via reverse proxy.

Migrating an Authentik Database

On the source machine, dump the database:

sudo docker exec authentik-postgres pg_dump -U authentik -F t authentik > /path/to/mydb.tar

Then transfer it to the target machine. On the target machine, copy the file into the Docker container:

cp /path/to/mydb.tar authentik-postgres:/path/to/wherever

(Optional) Purge existing tables:

sudo docker exec -i authentik-postgres psql -U authentik -c "SELECT pg_terminate_backend(pg_stat_activity.pid) FROM pg_stat_activity WHERE pg_stat_activity.datname = 'authentik' AND pid <> pg_backend_pid();" && sudo docker exec -i authentik-postgres psql -U authentik -d postgres -c "DROP DATABASE IF EXISTS authentik;" && sudo docker exec -i authentik-postgres psql -U authentik -d postgres -c "CREATE DATABASE authentik;"

Restore the database:

sudo docker exec authentik-postgresql pg_restore -U authentik -d authentik /path/to/wherever/mydb.tar