我的错误是我更换了hadoop集群的master，可是本机之前做了ssh免密，且与之前的master的hostname 一样，所以就报错了：
18/12/21 14:29:59 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable Starting namenodes on [master] master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: @ WARNING: POSSIBLE DNS SPOOFING DETECTED! @ master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: The RSA host key for master has changed, master: and the key for the corresponding IP address 10.10.22.133 master: is unknown. This could either mean that master: DNS SPOOFING is happening or the IP address for the host master: and its host key have changed at the same time. master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! master: Someone could be eavesdropping on you right now (man-in-the-middle attack)! master: It is also possible that a host key has just been changed. master: The fingerprint for the RSA key sent by the remote host is master: SHA256:QI8zeAiGqUYIA3Fihbg8iEdkKmbU++kbdinMI4F2ktA. master: Please contact your system administrator. master: Add correct host key in /root/.ssh/known_hosts to get rid of this message. master: Offending RSA key in /root/.ssh/known_hosts:7 master: RSA host key for master has changed and you have requested strict checking. master: Host key verification failed. master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: @ WARNING: POSSIBLE DNS SPOOFING DETECTED! @ master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: The RSA host key for master has changed, master: and the key for the corresponding IP address 10.10.22.133 master: is unknown. This could either mean that master: DNS SPOOFING is happening or the IP address for the host master: and its host key have changed at the same time. master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! master: Someone could be eavesdropping on you right now (man-in-the-middle attack)! master: It is also possible that a host key has just been changed. master: The fingerprint for the RSA key sent by the remote host is master: SHA256:QI8zeAiGqUYIA3Fihbg8iEdkKmbU++kbdinMI4F2ktA. master: Please contact your system administrator. master: Add correct host key in /root/.ssh/known_hosts to get rid of this message. master: Offending RSA key in /root/.ssh/known_hosts:7 master: RSA host key for master has changed and you have requested strict checking. master: Host key verification failed. Starting secondary namenodes [master] master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: @ WARNING: POSSIBLE DNS SPOOFING DETECTED! @ master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: The RSA host key for master has changed, master: and the key for the corresponding IP address 10.10.22.133 master: is unknown. This could either mean that master: DNS SPOOFING is happening or the IP address for the host master: and its host key have changed at the same time. master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! master: Someone could be eavesdropping on you right now (man-in-the-middle attack)! master: It is also possible that a host key has just been changed. master: The fingerprint for the RSA key sent by the remote host is master: SHA256:QI8zeAiGqUYIA3Fihbg8iEdkKmbU++kbdinMI4F2ktA. master: Please contact your system administrator. master: Add correct host key in /root/.ssh/known_hosts to get rid of this message. master: Offending RSA key in /root/.ssh/known_hosts:7 master: RSA host key for master has changed and you have requested strict checking. master: Host key verification failed. 18/12/21 14:30:03 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable starting yarn daemons starting resourcemanager, logging to /opt/hadoop/hadoop-2.7.7/logs/yarn-root-resourcemanager-slave2.out master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: @ WARNING: POSSIBLE DNS SPOOFING DETECTED! @ master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: The RSA host key for master has changed, master: and the key for the corresponding IP address 10.10.22.133 master: is unknown. This could either mean that master: DNS SPOOFING is happening or the IP address for the host master: and its host key have changed at the same time. master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ master: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ master: IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! master: Someone could be eavesdropping on you right now (man-in-the-middle attack)! master: It is also possible that a host key has just been changed. master: The fingerprint for the RSA key sent by the remote host is master: SHA256:QI8zeAiGqUYIA3Fihbg8iEdkKmbU++kbdinMI4F2ktA. master: Please contact your system administrator. master: Add correct host key in /root/.ssh/known_hosts to get rid of this message. master: Offending RSA key in /root/.ssh/known_hosts:7 master: RSA host key for master has changed and you have requested strict checking. master: Host key verification failed.
解决方法：
rm ~/.ssh/known_hosts
删除 konwn_hosts
