[NOTE] ssh免密登陆配置

第n次忘记

• 生成公钥ssh-keygen -t rsa
• scp -p id_rsa.pub hadoop@slave1:~/.ssh/id_rsa_master.pub
• 检查是否存在touch authorized_keys，并chmod 600 authorized_keys
• cat ~/.ssh/id_rsa_master.pub >> authorized_keyJ