RAFT: Add clarifying note for cluster/leave operation.

We had a user express confusion about the state of a cluster after using
cluster/leave. The user had a three server cluster and used
cluster/leave to remove two servers from the cluster. The user expected
that the single server left would not function since the quorum of two
servers for a three server cluster was not met.

In actuality, cluster/leave removes the server from the cluster and
alters the cluster size in the process. Thus the single remaining server
continued to function since quorum was reached.

This documentation change makes it a bit more explicit that
cluster/leave alters the size of the cluster and cites the three server
down to one server case as an example.

Reported-at: https://bugzilla.redhat.com/show_bug.cgi?id=1798158
Acked-by: Han Zhou <hzhou@ovn.org>
Signed-off-by: Mark Michelson <mmichels@redhat.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>

diff --git a/ovsdb/ovsdb-server.1.in b/ovsdb/ovsdb-server.1.in
index 338f3bc299d2c7a1dab7d7ecf8b373e8f2f311a6..6667553df0daffe974d00d93a1a742af76af9109 100644 (file)
--- a/ovsdb/ovsdb-server.1.in
+++ b/ovsdb/ovsdb-server.1.in
@@ -347,6 +347,11 @@ until the server has left the cluster.
 .IP
 Once a server leaves a cluster, it may never rejoin it.  Instead,
 create a new server and join it to the cluster.
+.IP
+Note that removing the server from the cluster alters the total size
+of the cluster. For example, if you remove two servers from a three
+server cluster, then the "cluster" becomes a single functioning server.
+This does not result in a three server cluster that lacks quorum.
 .
 .IP "\fBcluster/kick \fIdb server\fR"
 Start graceful removal of \fIserver\fR from \fIdb\fR's cluster, like