mon: refuse to stop mds if max_mds will make it rejoin

Otherwise the MDS will leave the cluster and immediately rejoin, which is useless and confusing to users. See ceph#1820. Signed-off-by: Sage Weil <[email protected]>
zmc · Feb 23, 2012 · 21c4313 · 21c4313
1 parent 963dec8
commit 21c4313
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/src/mon/MDSMonitor.cc b/src/mon/MDSMonitor.cc
@@ -728,6 +728,9 @@ bool MDSMonitor::prepare_command(MMonCommand *m)
 	r = -EBUSY;
 	ss << "can't tell the root (" << mdsmap.get_root() << ") or tableserver (" << mdsmap.get_tableserver()
 	   << " to stop unless it is the last mds in the cluster";
+      } else if (mdsmap.get_num_in_mds() <= mdsmap.get_max_mds()) {
+	r = -EBUSY;
+	ss << "must decrease max_mds or else MDS will rejoin after shutdown";
       } else {
 	r = 0;
 	uint64_t gid = pending_mdsmap.up[who];