Do not clear swarm directory at the begining of swarm init and swarm join now.

However, do clear the directory if init or join fails, because we don't
want to leave it in a half-finished state.

Signed-off-by: Ying Li <ying.li@docker.com>
(cherry picked from commit bf3e9293a66c77a2fddf4e691222898846b4af9f)

components/engine/daemon/cluster/swarm.go

@@ -88,10 +88,6 @@ func (c *Cluster) Init(req types.InitRequest) (string, error) {
 		}
 	}
 
-	if !req.ForceNewCluster {
-		clearPersistentState(c.root)
-	}
-
 	nr, err := c.newNodeRunner(nodeStartConfig{
 		forceNewCluster: req.ForceNewCluster,
 		autolock:        req.AutoLockManagers,
@@ -109,16 +105,14 @@ func (c *Cluster) Init(req types.InitRequest) (string, error) {
 	c.mu.Unlock()
 
 	if err := <-nr.Ready(); err != nil {
+		c.mu.Lock()
+		c.nr = nil
+		c.mu.Unlock()
 		if !req.ForceNewCluster { // if failure on first attempt don't keep state
 			if err := clearPersistentState(c.root); err != nil {
 				return "", err
 			}
 		}
-		if err != nil {
-			c.mu.Lock()
-			c.nr = nil
-			c.mu.Unlock()
-		}
 		return "", err
 	}
 	state := nr.State()
@@ -166,8 +160,6 @@ func (c *Cluster) Join(req types.JoinRequest) error {
 		return err
 	}
 
-	clearPersistentState(c.root)
-
 	nr, err := c.newNodeRunner(nodeStartConfig{
 		RemoteAddr:    req.RemoteAddrs[0],
 		ListenAddr:    net.JoinHostPort(listenHost, listenPort),
@@ -193,6 +185,9 @@ func (c *Cluster) Join(req types.JoinRequest) error {
 			c.mu.Lock()
 			c.nr = nil
 			c.mu.Unlock()
+			if err := clearPersistentState(c.root); err != nil {
+				return err
+			}
 		}
 		return err
 	}