vswitch.xml: Document iface-status behavior for intra-hypervisor migration.

Based on a face-to-face discussion.

CC: Natasha Gude <natasha@nicira.com>
CC: Andrew Lambeth <wal@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Ethan Jackson <ethan@nicira.com>

diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index e1d9372..30588a7 100644 (file)
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -1956,6 +1956,11 @@
           two different hypervisors.  That is, <code>active</code> means that
           this <ref column="external_ids" key="iface-id"/> is the active
           instance within a single hypervisor, not in a broader scope.
+          There is one exception: some hypervisors support ``migration'' from a
+          given hypervisor to itself (most often for test purposes).  During
+          such a ``migration,'' two instances of a single <ref
+          column="external_ids" key="iface-id"/> might both be briefly marked
+          <code>active</code> on a single hypervisor.
         </p>
       </column>