Greetings,
The EL7 RPM for repmgr94 creates a new system user repmgr and has repmgrd run as repmgr. Additionally when repmgr is invoked it expects read/write over the postgres data directories and the ability to invoke pg_ctl using system(...) which would require it to be either root or postgres. I took a look through the source and it appears repmgrd invokes repmgr using system(...) which would be running as the repmgr user and would fail. The repmgr example spec files, readme/instructions, and the official debian/ubuntu packages also assume repmgr and repmgrd run as postgres and do not create a new user. They also place all of the repmgr binaries, log file, and pid file in the same directories as postgres. If you used repmgr without repmgrd you would not notice, or you would not notice until it attempts to do automatic failover.