How to save the keycloak data when running inside docker container?

Keycloak comes with its own embedded Java-based relational database called H2. The data is stored in /opt/jboss/keycloak/standalone/data/ inside the container.

To start the container with a mounted volume you need:

1. Create a folder with read-write permissions:

mkdir -m 777 ./keycloak_data

2. Start the container with the mounted volume:

docker run -v ./keycloak_data:/opt/jboss/keycloak/standalone/data/ -p 8080:8080  -e KEYCLOAK_USER=admin -e KEYCLOAK_PASSWORD=admin quay.io/keycloak/keycloak:15.0.2

Note that if you mount the volume, the KEYCLOAK_USER and KEYCLOAK_PASSWORD will only be considered by the first start of the container, so to start the container again just use:

docker run -v ./keycloak_data:/opt/jboss/keycloak/standalone/data/ -p 8080:8080 quay.io/keycloak/keycloak:15.0.2