nodetool工具连接超时错误解决办法

nodetool查看本地集群状态时,N久以后出现无法连接、连接超时的错误提示:

$ nodetool status
nodetool: Failed to connect to '127.0.0.1:7199' - ConnectException: 'Connection timed out'.

经排查为/etc/hosts文件配置错误所致,文件中实际的主机名(不是localhost)对应的ip地址解析行设置错误,这是由于主机ip地址更换后未及时更新hosts文件所致。更改为正确的ip地址类似如下：

192.168.1.104   yoga.localdomain    yoga

然后重新启动cassandra服务

$ sudo /etc/init.d/cassandra restart
[ ok ] Restarting cassandra (via systemctl): cassandra.service.

或者

$ sudo systemctl restart cassandra.service

然后再重新执行

$ nodetool status
Datacenter: datacenter1
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
--  Address    Load       Tokens  Owns (effective)  Host ID                               Rack
UN  127.0.0.1  139.45 KB  256     100.0%            27e51705-c13d-4f4b-b4f8-de3759fcd895  rack1

如果cassandra尚未完全启动时就执行该命令，会有异常抛出，类似如下：

$ nodetool status
error: No nodes present in the cluster. Has this node finished starting up?
-- StackTrace --
java.lang.RuntimeException: No nodes present in the cluster. Has this node finished starting up?
        at org.apache.cassandra.dht.Murmur3Partitioner.describeOwnership(Murmur3Partitioner.java:129)
        at org.apache.cassandra.service.StorageService.effectiveOwnership(StorageService.java:3762)
        at org.apache.cassandra.service.StorageService.effectiveOwnership(StorageService.java:103)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:75)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:279)
        at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:112)
        at com.sun.jmx.mbeanserver.StandardMBeanIntrospector.invokeM2(StandardMBeanIntrospector.java:46)
        at com.sun.jmx.mbeanserver.MBeanIntrospector.invokeM(MBeanIntrospector.java:237)
        at com.sun.jmx.mbeanserver.PerInterface.invoke(PerInterface.java:138)
        at com.sun.jmx.mbeanserver.MBeanSupport.invoke(MBeanSupport.java:252)
        at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
        at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
        at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1487)
        at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:97)
        at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1328)
        at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1420)
        at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:848)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:322)
        at sun.rmi.transport.Transport$1.run(Transport.java:177)
        at sun.rmi.transport.Transport$1.run(Transport.java:174)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:173)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:556)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:811)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:670)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)

Mac OS X平台上/etc/hosts文件中根本就不设置主机名对应的IP地址解析,而出现的错误提示也略有不同:

nodetool: Failed to connect to '127.0.0.1:7199' - ConnectException: 'Operation timed out'.

解决办法也是一样的,对于动态ip的客户端测试环境而言,直接将主机名对应的ip设置为127.0.0.1亦可：

127.0.0.1 mba

重新加载cassandra就可以了

$ launchctl unload /usr/local/opt/cassandra/homebrew.mxcl.cassandra.plist
$ launchctl load /usr/local/opt/cassandra/homebrew.mxcl.cassandra.plist