@startDocuBlock JSF_get_admin_server_id
@brief Get to know the internal id of the server

@RESTHEADER{GET /_admin/server/id, Return id of a server in a cluster}

@RESTDESCRIPTION

Returns the id of a server in a cluster.
The id is empty if it is working in single server mode.

@RESTRETURNCODES

@RESTRETURNCODE{200}
Is returned in all cases.
@endDocuBlock