cp ~/.ssh/id_rsa.pub ~/.ssh/id_rsa.pub.100

把他们都发送一台机器上

scp -r ~/.ssh/id_rsa.pub.101 root@hadoop100:/root/hadoop/.ssh

现在都放到100这个机器上了。

3.把所有机器的公钥放到一个文件里面

cat ~/.ssh/id_rsa.pub.100 >> ~/.ssh/authorized_keys
cat ~/.ssh/id_rsa.pub.101 >> ~/.ssh/authorized_keys
cat ~/.ssh/id_rsa.pub.102 >> ~/.ssh/authorized_keys

4.把该文件的权限修改为

chmod 644 authorized_keys

5.把生成的authorized_keys文件都复制一份到其他机器上

scp -r ~/.ssh/authorized_keys root@hadoop101:/root/hadoop/.ssh

重复步聚4.现在所有的机器都可以互相免登录了！