Centos 7 ssh秘钥认证（无需密码ssh）

今天在spark 中运行start-all.sh 时出现：

[root@master sbin]# ./stop-all.sh
root@slave1's password: root@master's password:
root@master's password: master: Permission denied, please try again.

原来是忘记配置ssh密钥认证了，步骤如下：
环境：
192.168.88.30 master
192.168.88.31 slave1

第一步，生成秘钥：
master和slave 上都运行一次，生成共有秘钥：

[root@master spark]# ssh-keygen -t rsa

一直回车，会生成如下文件：

/root/.ssh/id_rsa.pub

在master 和slave上重命名秘钥文件：

[root@slave1 .ssh]# cp id_rsa.pub id_rsa_slave.pub
[root@master .ssh]# cp id_rsa.pub id_rsa_master.pub

第二步，相互拷贝：

[root@slave1 .ssh]# scp master:/root/.ssh/id_rsa_master.pub  ~/.ssh/
[root@master .ssh]# scp slave1:/root/.ssh/id_rsa_slave.pub  ~/.ssh/

第三步，分别追加到认证文件：
slave1:

[root@slave1 .ssh]# cat id_rsa_slave.pub >> authorized_keys
[root@slave1 .ssh]# cat id_rsa_master.pub >> authorized_keys
master:
[root@master .ssh]# cat id_rsa_slave.pub >> authorized_keys
[root@master .ssh]# cat id_rsa_master.pub >> authorized_keys

第四步，修改权限：
slave1:

[root@slave1 ~]# chmod 700 .ssh
[root@slave1 ~]# chmod 600 .ssh/authorized_keys
master:
[root@master ~]# chmod 700 .ssh
[root@master ~]# chmod 600 .ssh/authorized_keys

第五步，重启sshd：

[root@slave1 ~]# systemctl restart sshd
[root@master ~]# systemctl restart sshd

设置完成
验证：
slave 无密码ssh 到master

[root@slave1 .ssh]# ssh master
Last login: Sun Jun 26 17:45:44 2016 from 192.168.88.7
[root@master ~]#

反过来同样OK！

同样SPARK 启动成功：

[root@master sbin]# ./start-all.sh
starting org.apache.spark.deploy.master.Master, logging to /spark/spark-1.6.1-bin-hadoop2.6/logs/spark-root-org.apache.spark.deploy.master.Master-1-master.out
slave1: starting org.apache.spark.deploy.worker.Worker, logging to /spark/spark-1.6.1-bin-hadoop2.6/logs/spark-root-org.apache.spark.deploy.worker.Worker-1-slave1.out
master: starting org.apache.spark.deploy.worker.Worker, logging to /spark/spark-1.6.1-bin-hadoop2.6/logs/spark-root-org.apache.spark.deploy.worker.Worker-1-master.out
[root@master sbin]#