The IDM relies on an LDAP directory which needs share some of the pre conditions on the LDAP side (e.g. deployed custom attributes/schemas, matching slapd configs to e.g. ensure that uid/gid/cn are unique attributes, the memberof overlay and more.
To be able to effectively deploy this to CI and to allow contributors/developers to test changes, we should create a container with all prerequisites and deploy it to the Wikimedia Docker registry.