Dockerize Keycloak 21 with a custom theme

3 min readJun 17, 2023

What will we accomplish?

Dockerizing the latest Keycloak 21
Customize the welcome, login, and admin console page

Dockerizing Keycloak 21

Create a folder that will hold all our files and folder — custom-auth-service
Inside the custom-auth-service folder create a file called Dockerfile with the content below that will help us build our Keycloak docker image

FROM quay.io/keycloak/keycloak:21.0 as builder

# Configure a database vendor
ENV KC_DB=postgres

WORKDIR /opt/keycloak

# for demonstration purposes only, please make sure to use proper certificates in production instead
RUN keytool -genkeypair -storepass password -storetype PKCS12 -keyalg RSA -keysize 2048 -dname "CN=server" -alias server -ext "SAN:c=DNS:localhost,IP:127.0.0.1" -keystore conf/server.keystore

RUN /opt/keycloak/bin/kc.sh build

FROM quay.io/keycloak/keycloak:latest
COPY --from=builder /opt/keycloak/ /opt/keycloak/

ENTRYPOINT ["/opt/keycloak/bin/kc.sh"]

Create a docker-compose.yaml file that will spin up Postgres DB(Database used by Keycloak to store all data) and a Keycloak instance created from the image built from the above Dockerfile.

version: '3'

volumes:
  keycloak-db-data:
    driver: local

services:
  postgres:
    image: postgres:13.7
    container_name: postgres
    volumes:
      - keycloak-db-data:/var/lib/postgresql/data
    environment:
      POSTGRES_DB: keycloak
      POSTGRES_USER: my_keycloak
      POSTGRES_PASSWORD: My863Keycloak
  keycloak:
    build: .
    container_name: custom-auth-service
    environment:
      #Admin Credentials
      KC_HOSTNAME_STRICT: 'false'
      KC_HOSTNAME_STRICT_HTTPS: 'false'
      KEYCLOAK_ADMIN: admin
      KEYCLOAK_ADMIN_PASSWORD: MyKeycloak493
      KEYCLOAK_USER: admin
      KEYCLOAK_PASSWORD: MyKeycloak493
      KC_DB_URL: 'jdbc:postgresql://postgres/keycloak'
      KC_DB_USERNAME: my_keycloak
      KC_DB_PASSWORD: My863Keycloak
      KC_HEALTH_ENABLED: 'true'
      KC_METRICS_ENABLED: 'true'
      KC_HOSTNAME: localhost
      PROXY_ADDRESS_FORWARDING: "true"
    command:
      - "-v start --optimized
      "
    ports:
      - 8443:8443
      - 8080:8080
    depends_on:
      - postgres

Build Keycloak image

docker-compose build

Start keycloak

docker-compose up

Custom Theme in a Dockerized Keycloak 21

Inside the custom-auth-service folder create a folder named themes. copy the my-theme folder and all its content inside the themes folder from here.
Update the Dockerfile to copy my-theme folder from to the image

FROM quay.io/keycloak/keycloak:21.0 as builder

# Configure a database vendor
ENV KC_DB=postgres

WORKDIR /opt/keycloak

# for demonstration purposes only, please make sure to use proper certificates in production instead
RUN keytool -genkeypair -storepass password -storetype PKCS12 -keyalg RSA -keysize 2048 -dname "CN=server" -alias server -ext "SAN:c=DNS:localhost,IP:127.0.0.1" -keystore conf/server.keystore

RUN /opt/keycloak/bin/kc.sh build

FROM quay.io/keycloak/keycloak:latest
COPY --from=builder /opt/keycloak/ /opt/keycloak/

COPY ./themes/my-theme/ /opt/keycloak/themes/my-theme

ENTRYPOINT ["/opt/keycloak/bin/kc.sh"]