add method findOneInUpState to get mgmt server from class name

Author: weizhouapache

framework/cluster/src/main/java/com/cloud/cluster/dao/ManagementServerHostDao.java

@@ -57,4 +57,6 @@ public interface ManagementServerHostDao extends GenericDao<ManagementServerHost
     ManagementServerHostVO findOneInUpState(Filter filter);
 
     ManagementServerHostVO findOneInUpStateByLongestRuntime();
+
+    ManagementServerHostVO findOneInUpState(String className);
 }

framework/cluster/src/main/java/com/cloud/cluster/dao/ManagementServerHostDaoImpl.java

@@ -282,4 +282,15 @@ public ManagementServerHostVO findOneInUpStateByLongestRuntime() {
         return CollectionUtils.isNotEmpty(msHosts) ? msHosts.get(0) : null;
     }
 
+    @Override
+    public ManagementServerHostVO findOneInUpState(String className) {
+        SearchCriteria<ManagementServerHostVO> sc = StateSearch.create();
+        sc.setParameters("state", ManagementServerHost.State.Up);
+        List<ManagementServerHostVO> mshosts = listBy(sc, null);
+        if (CollectionUtils.isEmpty(mshosts)) {
+            return null;
+        }
+        int offset = (className == null) ? 0 : (className.length() % mshosts.size());
+        return mshosts.get(offset);
+    }
 }

server/src/main/java/org/apache/cloudstack/vm/schedule/VMSchedulerImpl.java

@@ -196,7 +196,7 @@ public boolean start() {
         final TimerTask schedulerPollTask = new ManagedContextTimerTask() {
             @Override
             protected void runInContext() {
-                ManagementServerHostVO msHost = managementServerHostDao.findOneInUpStateByLongestRuntime();
+                ManagementServerHostVO msHost = managementServerHostDao.findOneInUpState(this.getClass().getSimpleName());
                 if (msHost == null || (msHost.getMsid() != ManagementServerNode.getManagementServerId())) {
                     logger.debug("Skipping the vm scheduler poll task on this management server");
                     return;