这个问题定位了2天，始终不知道是什么原因。
Cloudstack版本：4.4.4
xenserver版本：6.2.0
Cloudstack和xenserver安装完毕后，通过cloudstack管理界面中添加主机，添加失败。
但是Host配置已经有了，再次尝试“force reconnect”,提示“Failed to reconnect host”。
打开cloudstack日志：/var/log/cloudstack/management/management-server.log
显示如下信息：
2016-03-13 09:22:14,541 DEBUG c.c.a.ApiServlet ===START=== 192.168.1.31 -- GET command=reconnectHost&id=fa6d6aa4-0ef0-4acb-95f6-82da74652c72&response=json&sessionkey=gZrrdnrUiU1Hq0IKlzFI37EAezE%3D&_=1457832135163
2016-03-13 09:22:14,566 DEBUG o.a.c.f.j.i.AsyncJobManagerImpl submit async job-37, details: AsyncJobVO {id:37, userId: 2, accountId: 2, instanceType: Host, instanceId: 2, cmd: org.apache.cloudstack.api.command.admin.host.ReconnectHostCmd, cmdInfo: {"response":"json","id":"fa6d6aa4-0ef0-4acb-95f6-82da74652c72","sessionkey":"gZrrdnrUiU1Hq0IKlzFI37EAezE\u003d","ctxDetails":"{\"com.cloud.host.Host\":\"fa6d6aa4-0ef0-4acb-95f6-82da74652c72\"}","cmdEventType":"HOST.RECONNECT","ctxUserId":"2","httpmethod":"GET","_":"1457832135163","uuid":"fa6d6aa4-0ef0-4acb-95f6-82da74652c72","ctxAccountId":"2","ctxStartEventId":"55"}, cmdVersion: 0, status: IN_PROGRESS, processStatus: 0, resultCode: 0, result: null, initMsid: 126111260571413, completeMsid: null, lastUpdated: null, lastPolled: null, created: null}
2016-03-13 09:22:14,568 DEBUG c.c.a.ApiServlet ===END=== 192.168.1.31 -- GET command=reconnectHost&id=fa6d6aa4-0ef0-4acb-95f6-82da74652c72&response=json&sessionkey=gZrrdnrUiU1Hq0IKlzFI37EAezE%3D&_=1457832135163
2016-03-13 09:22:14,586 INFO o.a.c.f.j.i.AsyncJobMonitor Add job-37 into job monitoring
2016-03-13 09:22:14,587 DEBUG o.a.c.f.j.i.AsyncJobManagerImpl Executing AsyncJobVO {id:37, userId: 2, accountId: 2, instanceType: Host, instanceId: 2, cmd: org.apache.cloudstack.api.command.admin.host.ReconnectHostCmd, cmdInfo: {"response":"json","id":"fa6d6aa4-0ef0-4acb-95f6-82da74652c72","sessionkey":"gZrrdnrUiU1Hq0IKlzFI37EAezE\u003d","ctxDetails":"{\"com.cloud.host.Host\":\"fa6d6aa4-0ef0-4acb-95f6-82da74652c72\"}","cmdEventType":"HOST.RECONNECT","ctxUserId":"2","httpmethod":"GET","_":"1457832135163","uuid":"fa6d6aa4-0ef0-4acb-95f6-82da74652c72","ctxAccountId":"2","ctxStartEventId":"55"}, cmdVersion: 0, status: IN_PROGRESS, processStatus: 0, resultCode: 0, result: null, initMsid: 126111260571413, completeMsid: null, lastUpdated: null, lastPolled: null, created: null}
2016-03-13 09:22:14,599 INFO c.c.a.m.AgentManagerImpl Unable to disconnect host because it is not connected to this server: 2
2016-03-13 09:22:14,599 WARN o.a.c.a.c.a.h.ReconnectHostCmd Exception:
org.apache.cloudstack.api.ServerApiException: Failed to reconnect host
at org.apache.cloudstack.api.command.admin.host.ReconnectHostCmd.execute(ReconnectHostCmd.java:109)
at com.cloud.api.ApiDispatcher.dispatch(ApiDispatcher.java:141)
at com.cloud.api.ApiAsyncJobDispatcher.runJob(ApiAsyncJobDispatcher.java:108)
at org.apache.cloudstack.framework.jobs.impl.AsyncJobManagerImpl$5.runInContext(AsyncJobManagerImpl.java:502)
at org.apache.cloudstack.managed.context.ManagedContextRunnable$1.run(ManagedContextRunnable.java:49)
at org.apache.cloudstack.managed.context.impl.DefaultManagedContext$1.call(DefaultManagedContext.java:56)
at org.apache.cloudstack.managed.context.impl.DefaultManagedContext.callWithContext(DefaultManagedContext.java:103)
at org.apache.cloudstack.managed.context.impl.DefaultManagedContext.runWithContext(DefaultManagedContext.java:53)
at org.apache.cloudstack.managed.context.ManagedContextRunnable.run(ManagedContextRunnable.java:46)
at org.apache.cloudstack.framework.jobs.impl.AsyncJobManagerImpl$5.run(AsyncJobManagerImpl.java:459)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
2016-03-13 09:22:14,601 DEBUG o.a.c.f.j.i.AsyncJobManagerImpl Complete async job-37, jobStatus: FAILED, resultCode: 530, result: org.apache.cloudstack.api.response.ExceptionResponse/null/{"uuidList":[],"errorcode":534,"errortext":"Failed to reconnect host"}
还请大虾帮忙看看有没有遇到类似的问题，多谢！！
