There was some issue with the error handling in engine side while removing a host from cluster.
1. When remove host fails in the Gluster side, host was getting removed from Engine DB and RHSC-UI.
Error handling was corrected in engine side to handle the errors returned from VDSM/GLUSTER in remove host (gluster peer detach).
When remove host fails in the VDSM/GLUSTER side and if the reason is that the host being removed is not part of the cluster(Host is already from gluster using CLI) then it will be removed from Engine DB. But if the remove host fails in server VDSM/GLuster side because of some other reason, then host will not be removed from engine DB and an appropriate event message will be shown in the events tab.