@@ -471,6 +471,57 @@ func (s *DockerSwarmSuite) TestApiSwarmLeaderProxy(c *check.C) {

 	}

 }

+func (s *DockerSwarmSuite) TestApiSwarmLeaderElection(c *check.C) {

+	// Create 3 nodes

+	d1 := s.AddDaemon(c, true, true)

+	d2 := s.AddDaemon(c, true, true)

+	d3 := s.AddDaemon(c, true, true)

+

+	// assert that the first node we made is the leader, and the other two are followers

+	c.Assert(d1.getNode(c, d1.NodeID).ManagerStatus.Leader, checker.True)

+	c.Assert(d1.getNode(c, d2.NodeID).ManagerStatus.Leader, checker.False)

+	c.Assert(d1.getNode(c, d3.NodeID).ManagerStatus.Leader, checker.False)

+

+	leader := d1

+

+	// stop the leader

+	leader.Stop()

+

+	// wait for an election to occur

+	var newleader *SwarmDaemon

+

+	for _, d := range []*SwarmDaemon{d2, d3} {

+		if d.getNode(c, d.NodeID).ManagerStatus.Leader {

+			newleader = d

+			break

+		}

+	}

+

+	// assert that we have a new leader

+	c.Assert(newleader, checker.NotNil)

+

+	// add the old leader back

+	leader.Start()

+

+	// clear leader and reinit the followers list

+	followers := make([]*SwarmDaemon, 0, 3)

+

+	// pick out the leader and the followers again

+	for _, d := range []*SwarmDaemon{d1, d2, d3} {

+		if d1.getNode(c, d.NodeID).ManagerStatus.Leader {

+			leader = d

+		} else {

+			followers = append(followers, d)

+		}

+	}

+

+	// verify that we still only have 1 leader and 2 followers

+	c.Assert(leader, checker.NotNil)

+	c.Assert(followers, checker.HasLen, 2)

+	// and that after we added d1 back, the leader hasn't changed

+	c.Assert(leader.NodeID, checker.Equals, newleader.NodeID)

+}

+

 func (s *DockerSwarmSuite) TestApiSwarmRaftQuorum(c *check.C) {

 	testRequires(c, Network)

 	d1 := s.AddDaemon(c, true, true)