From: Sage Weil <sage@redhat.com>
Date: Tue, 4 Apr 2017 18:27:54 +0000 (-0400)
Subject: mgr/Mgr: fix map waits in init
X-Git-Tag: v12.0.2~166^2~3
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=6d5e0132d97864f1058ba86584e2cc0e565977e7;p=ceph.git

mgr/Mgr: fix map waits in init

If we go active multiple times we may already have an fsmap
subscription registered via MonClient, which means that we
won't receive a net new FSMap during the init phase.  This is
trivial to reproduce; just 'ceph mgr fail x' and when it
activates the second time init() will get stuck waiting.

The core issue is that monc subs are stateful, but we forget
the various maps with the previous Mgr incarnation.  Sipmle
workaround is to reset the mon connection as we init.

Signed-off-by: Sage Weil <sage@redhat.com>
---

diff --git a/src/mgr/Mgr.cc b/src/mgr/Mgr.cc
index a0e908eecf69..5fa65f7b7575 100644
--- a/src/mgr/Mgr.cc
+++ b/src/mgr/Mgr.cc
@@ -162,10 +162,19 @@ void Mgr::init()
   dout(4) << "Loading daemon metadata..." << dendl;
   load_all_metadata();
 
-  // Preload config keys (`get` for plugins is to be a fast local
-  // operation, we we don't have to synchronize these later because
-  // all sets will come via mgr)
-  load_config();
+  // subscribe to all the maps
+  monc->sub_want("log-info", 0, 0);
+  monc->sub_want("mgrdigest", 0, 0);
+  monc->sub_want("fsmap", 0, 0);
+
+  dout(4) << "waiting for OSDMap..." << dendl;
+  // Subscribe to OSDMap update to pass on to ClusterState
+  objecter->maybe_request_map();
+
+  // reset the mon session.  we get these maps through subscriptions which
+  // are stateful with the connection, so even if *we* don't have them a
+  // previous incarnation sharing the same MonClient may have.
+  monc->reopen_session();
 
   // Start Objecter and wait for OSD map
   lock.Unlock();  // Drop lock because OSDMap dispatch calls into my ms_dispatch
@@ -177,22 +186,17 @@ void Mgr::init()
     cluster_state.notify_osdmap(osd_map);
   });
 
-  // Subscribe to OSDMap update to pass on to ClusterState
-  objecter->maybe_request_map();
-
-  monc->sub_want("log-info", 0, 0);
-  monc->sub_want("mgrdigest", 0, 0);
-
-  // Prepare to receive FSMap and request it
-  monc->sub_want("fsmap", 0, 0);
-  monc->renew_subs();
-
   // Wait for FSMap
   dout(4) << "waiting for FSMap..." << dendl;
   while (!cluster_state.have_fsmap()) {
     fs_map_cond.Wait(lock);
   }
 
+  dout(4) << "waiting for config-keys..." << dendl;
+  // Preload config keys (`get` for plugins is to be a fast local
+  // operation, we we don't have to synchronize these later because
+  // all sets will come via mgr)
+  load_config();
 
   // Wait for MgrDigest...?
   // TODO