make it easy with setting up multiple masters in a clcuster

docker/local-cluster-compose.yml

@@ -6,19 +6,19 @@ services:
     ports:
       - 9333:9333
       - 19333:19333
-    command: "master -ip=master0 -port=9333 -peers=master0:9333,master1:9334,master2:9335"
+    command: "master -ip=master0 -port=9333 -peers=master0:9333,master1:9334,master2:9335 -mdir=/data/m1"
   master1:
     image: chrislusf/seaweedfs:local
     ports:
       - 9334:9334
       - 19334:19334
-    command: "master -ip=master1 -port=9334 -peers=master0:9333,master1:9334,master2:9335"
+    command: "master -ip=master1 -port=9334 -peers=master0:9333,master1:9334,master2:9335 -mdir=/data/m2"
   master2:
     image: chrislusf/seaweedfs:local
     ports:
       - 9335:9335
       - 19335:19335
-    command: "master -ip=master2 -port=9335 -peers=master0:9333,master1:9334,master2:9335"
+    command: "master -ip=master2 -port=9335 -peers=master0:9333,master1:9334,master2:9335 -mdir=/data/m3"
   volume:
     image: chrislusf/seaweedfs:local
     ports:

weed/command/master.go

@@ -89,6 +89,10 @@ func runMaster(cmd *Command, args []string) bool {
 	runtime.GOMAXPROCS(runtime.NumCPU())
 	grace.SetupProfiling(*masterCpuProfile, *masterMemProfile)
 
+	parent, _ := util.FullPath(*m.metaFolder).DirAndName()
+	if util.FileExists(string(parent)) && !util.FileExists(*m.metaFolder){
+		os.MkdirAll(*m.metaFolder, 0755)
+	}
 	if err := util.TestFolderWritable(util.ResolvePath(*m.metaFolder)); err != nil {
 		glog.Fatalf("Check Meta Folder (-mdir) Writable %s : %s", *m.metaFolder, err)
 	}