[keycloak-user] Removing Mongo support from Keycloak

[Stian Thorgersen]

At times you have to make hard decisions and this has been one of those. We
have decided to remove Mongo support from Keycloak. The primary motivation
behind this decision is that we simply don't have the resources to maintain
and further develop the back-end for both relational databases and Mongo.
Further, there are some fundamental issues with our current use of Mongo
that would require a large amount of work to become fully production ready.
This primarily boils down to the lack of ACID transactions in Mongo.

We hope that this decision won't result in too much trouble for those of
you that are currently using Mongo as the back-end for Keycloak. It should
be relatively painless to migrate to a relational database with our
export/import feature. If you do run into issues with this please let us
know on the mailing list and we will do whatever we can to help make the
transition as smooth as possible.

If anyone from the community would like to take over the Mongo support and
maintain it as a separate extension please let us know. We can help with
extracting the code and work together in making it easy to install it as an
extension.
Migrating from Mongo to relational database

First step is to export the full database. You can do this by stopping the
Keycloak server and running:
bin/standalone.sh -Dkeycloak.migration.action=export
-Dkeycloak.migration.provider=dir -Dkeycloak.migration.dir=backup

This will export all data from Mongo to JSON files within the directory
backup. For full details refer to the Server Administration Guide
<https://keycloak.gitbooks.io/server-adminstration-guide/content/topics/export-import.html>
.

Next step is to install a relational database and configure it in Keycloak.
Take your pick we support quite a few. For full details refer to the Server
Installation Guide
<https://keycloak.gitbooks.io/server-installation-and-configuration/content/topics/database.html>
.

Once you have the relational database ready and configured, you can start
Keycloak and import the data exported from Mongo. To do this run Keycloak
with:
bin/standalone.sh -Dkeycloak.migration.action=import
-Dkeycloak.migration.provider=dir -Dkeycloak.migration.dir=backup

Hopefully you're now up and running with all your realms and users migrated
to the relational database. If not, let us know on the user mailing list
and we'll help you out as soon as possible.