NameNode: Unable to trigger a roll of the active NN

I have backport Multi-standby NNs to our own hdfs version. I found an issue of EditLog roll.

Reproducible Steps：

1.original state

nn1 active

nn2 standby

nn3 standby

2. stop nn1

3. new state

nn1 stopped

nn2 active

nn3 standby

4. nn3 unable to trigger a roll of the active NN

[2018-08-22T10:33:38.025+08:00] [WARN] namenode.ha.EditLogTailer.triggerActiveLogRoll(EditLogTailer.java 307) [Edit log tailer] : Unable to trigger a roll of the active NN
java.net.ConnectException: Call From <nn3 hostname> to <nn1 hostname> failed on connection exception: java.net.ConnectException: Connection refused; For more details see:http://wiki.apache.org/hadoop/ConnectionRefused
at sun.reflect.GeneratedConstructorAccessor17.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.apache.hadoop.net.NetUtils.wrapWithMessage(NetUtils.java:782)
at org.apache.hadoop.net.NetUtils.wrapException(NetUtils.java:722)
at org.apache.hadoop.ipc.Client.call(Client.java:1536)
at org.apache.hadoop.ipc.Client.call(Client.java:1463)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:237)
at com.sun.proxy.$Proxy16.rollEditLog(Unknown Source)
at org.apache.hadoop.hdfs.protocolPB.NamenodeProtocolTranslatorPB.rollEditLog(NamenodeProtocolTranslatorPB.java:148)
at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$2.doWork(EditLogTailer.java:301)
at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$2.doWork(EditLogTailer.java:298)
at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$MultipleNameNodeProxy.call(EditLogTailer.java:414)
at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer.triggerActiveLogRoll(EditLogTailer.java:304)
at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer.access$800(EditLogTailer.java:69)
at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.doWork(EditLogTailer.java:346)
at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.access$400(EditLogTailer.java:315)
at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread$1.run(EditLogTailer.java:332)
at org.apache.hadoop.security.SecurityUtil.doAsLoginUserOrFatal(SecurityUtil.java:415)
at org.apache.hadoop.hdfs.server.namenode.ha.EditLogTailer$EditLogTailerThread.run(EditLogTailer.java:328)
Caused by: java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717)
at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206)
at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:521)
at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:485)
at org.apache.hadoop.ipc.Client$Connection.setupConnection(Client.java:658)
at org.apache.hadoop.ipc.Client$Connection.setupIOstreams(Client.java:756)
at org.apache.hadoop.ipc.Client$Connection.access$2800(Client.java:419)
at org.apache.hadoop.ipc.Client.getConnection(Client.java:1585)
at org.apache.hadoop.ipc.Client.call(Client.java:1502)
... 14 more