1. 先切换到hdfs 用户，做免密码登录
ssh -keygen -t rsa
touch /var/lib/hadoop-hdfs/.ssh/authorized_keys
chmod 755 /var/lib/hadoop-hdfs/.ssh/authorized_keys
把两台hdfs 用户的id_rsa.pub 分别写入对方的authorized_keys文件中
2. 在两台机器上创建 /home/hdfs/.ssh
把两台机器hdfs 用户的 id_rsa 都拷到各自的 /home/hdfs/.ssh
chown hdfs:hdfs -R /home/hdfs/
3. 在hdfs-site.xml 配置
<property>
<name>dfs.ha.fencing.ssh.private-key-files</name>
<value>/home/hdfs/.ssh/id_rsa_1,/home/hdfs/.ssh/id_rsa_2</value>
</property>