Hadoop启动时RPC交互的过程

NameNode向NameNode请求getProtocolVersion()

DataNode向NameNode请求getProtocolVersion()
DataNode向NameNode请求versionRequest()
DataNode向NameNode发送register()
DataNode向NameNode发送sendHeartbeat()
DataNode向NameNode发送blockReport()

JobTracker向NameNode请求getProtocolVersion()
TaskTracker向JobTracker请求getProtocolVersion()

DataNode向NameNode发送sendHeartbeat()...

JobTracker向NameNode请求getFileInfo(/mapred/system),getListing()并delete()...(HDFS还在保护模式所以反复请求删除)
JobTracker向NameNode请求mkdirs(/mapred/system, rwxr-xr-x)
JobTracker向NameNode请求setPermission(/mapred/system, rwx------)
JobTracker向NameNode请求getFileInfo(/mapred/system/jobtracker.info)
JobTracker向NameNode请求getFileInfo(/mapred/system/jobtracker.info.recover)
JobTracker向NameNode请求create(/mapred/system/jobtracker.info, rwxr-xr-x)
JobTracker向NameNode请求setPermission(/mapred/system/jobtracker.info, rwx------)
JobTracker向NameNode请求addBlock(/mapred/system/jobtracker.info)
JobTracker向NameNode请求renewLease()
JobTracker向NameNode请求complete(/mapred/system/jobtracker.info)

DataNode向NameNode发送blockReceived()

TaskTracker向JobTracker请求getBuildVersion()
TaskTracker向JobTracker请求getSystemDir()
TaskTracker向NameNode请求getProtocolVersion()

DataNode向NameNode发送sendHeartbeat()...
TaskTracker向JobTracker发送heartbeat()...