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Keycloak (in Docker Swarm)

Keycloak is "an open source identity and access management solution". Using a local database, or a variety of backends (think OpenLDAP), you can provide Single Sign-On (SSO) using OpenID, OAuth 2.0, and SAML.

Keycloak's OpenID provider can also be used in combination with Traefik Forward Auth, to protect vulnerable services with an extra layer of authentication.

Keycloak Screenshot

Keycloak Requirements


Already deployed:



Keycloak filesystem paths

We'll need several directories to bind-mount into our container for both runtime and backup data, so create them as per the following example:

mkdir -p /var/data/runtime/keycloak/database
mkdir -p /var/data/keycloak/database-dump

Keycloak environment vars

Create /var/data/config/keycloak/keycloak.env, and populate with the following example variables, customized for your own domain structure.

# Technically, this could be auto-detected, but we prefer to be prescriptive

# This is required to run keycloak behind traefik

# What's our hostname?

# Tell Postgress what user/password to create

Create /var/data/config/keycloak/keycloak-backup.env, and populate with the following, so that your database can be backed up to the filesystem, daily:


Docker compose example

Create a Keycloak docker-compose (v3) stack config file, something like this example:

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version: '3'

    image: jboss/keycloak
    env_file: /var/data/config/keycloak/keycloak.env
      - /etc/localtime:/etc/localtime:ro
      - traefik_public
      - internal
        # traefik
        - traefik.enable=true

        # traefikv1
        - traefik.port=8080

        # traefikv2
        - "traefik.http.routers.keycloak.rule=Host(``)"
        - "traefik.http.routers.keycloak.entrypoints=https"
        - ""

    env_file: /var/data/config/keycloak/keycloak.env
    image: postgres:10.1
      - /var/data/runtime/keycloak/database:/var/lib/postgresql/data
      - /etc/localtime:/etc/localtime:ro
      - internal

    image: postgres:10.1
    env_file: /var/data/config/keycloak/keycloak-backup.env
      - /var/data/keycloak/database-dump:/dump
      - /etc/localtime:/etc/localtime:ro
    entrypoint: |
      bash -c 'bash -s <<EOF
      trap "break;exit" SIGHUP SIGINT SIGTERM
      sleep 2m
      while /bin/true; do
        pg_dump -Fc > /dump/dump_\`date +%d-%m-%Y"_"%H_%M_%S\`.psql
        (ls -t /dump/dump*.psql|head -n $$BACKUP_NUM_KEEP;ls /dump/dump*.psql)|sort|uniq -u|xargs rm -- {}
        sleep $$BACKUP_FREQUENCY
      - internal

    external: true
    driver: overlay
        - subnet:


Setup unique static subnets for every stack you deploy. This avoids IP/gateway conflicts which can otherwise occur when you're creating/removing stacks a lot. See my list here.

Run Keycloak

Launch Keycloak docker-swarm stack

Launch the Keycloak stack by running docker stack deploy keycloak -c <path -to-docker-compose.yml>

Log into your new instance at https://YOUR-FQDN, and login with the user/password you defined in keycloak.env.

Create Keycloak user

Why are we adding a user when I have an admin user already?

Do you keep a spare set of house keys somewhere other than your house? Do you login as root onto all your systems? Think of this as the same prinicple - lock the literal admin account away somewhere as a "password of last resort", and create a new user for your day-to-day interaction with Keycloak.

Within the "Master" realm (no need for more realms yet), navigate to Manage -> Users, and then click Add User at the top right:

Navigating to the add user interface in Keycloak

Populate your new user's username (it's the only mandatory field)

Populating a username in the add user interface in Keycloak

Set Keycloak user credentials

Once your user is created, to set their password, click on the "Credentials" tab, and procede to reset it. Set the password to non-temporary, unless you like extra work!

Resetting a user's password in Keycloak


Keycloak with Traefik

Keycloak can be used with Traefik in two ways..

Keycloak behind Traefik

You'll notice that the docker compose example above includes labels for both Traefik v2 and Traefik v2. You obviously don't need both (although it wont't hurt), but make sure you update the example domain in the Traefik labels. Keycloak should work behind Traefik without any further customization.

Keycloak as Traefik middleware

Irrespective of whether Keycloak itself is behind Traefik, you can secure access to other services behind Traefik using Keycloak, using the Traefik Forward Auth middleware. Other similar middleware solutions are traefik-gatekeeper, and oauth2-proxy.

Keycloak Troubleshooting

Something didn't work? Try the following:

  1. Confirm that Keycloak did, in fact, start, by looking at the state of the stack, with docker stack ps keycloak --no-trunc

Chef's notes 📓

  1. For more geeky painfun, try integrating Keycloak with OpenLDAP for an authentication backend! 

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