Keycloak export in Docker and Exit

keycloak-export-docker.sh

# If something goes wrong, this script does not run forever but times out
TIMEOUT_SECONDS=300
# Logfile for the keycloak export instance
LOGFILE=/tmp/standalone.sh.log
# destionation export file
JSON_EXPORT_FILE=/tmp/realms-export-single-file.json

rm -f ${LOGFILE} ${JSON_EXPORT_FILE}

# Start a new keycloak instance with exporting options enabled.
# Use prot offset to prevent port conflicts with the "real" keycloak instance.
timeout ${TIMEOUT_SECONDS}s \
    /opt/jboss/keycloak/bin/standalone.sh \
        -Dkeycloak.migration.action=export \
        -Dkeycloak.migration.provider=singleFile \
        -Dkeycloak.migration.file=${JSON_EXPORT_FILE} \
        -Djboss.socket.binding.port-offset=99 \
    > ${LOGFILE} &

# Grab the keycloak export instance process id
PID="${!}"

# Wait for the export to finish
timeout ${TIMEOUT_SECONDS}s \
    grep -m 1 "Export finished successfully" <(tail -f ${LOGFILE})

# Stop the keycloak export instance
kill ${PID}

# Optional reload the keycloak instance
/opt/jboss/keycloak/bin/jboss-cli.sh --connect command=:reload

Move the script to the keycloak docker as a volume.
Get the name of keycloak container:
docker ps
Run the following command:
docker exec <keycloak_container_name_or_id> /bin/bash /tmp/keycloak-export-docker.sh

Ref:https://stackoverflow.com/a/60972882/7541412