Centos7 集群SSH无密码用户免密登录配置

例：配置集群1的A,B,C三台Centos7的test无密码用户免密登录

1，在A机器执行ssh-kengen生成秘钥，一路回车

[root@lms lms]# su - test
[test@test ~]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:0jykURKZQMKvbEhlncm6Kef2ZH8mYwRUlYsdj1nzjZ0 root@lms
The key's randomart image is:
+---[RSA 2048]----+
| ...=.*=o..      |
|  .+ *oo o o     |
|  o.o . + B o + .|
| . ... B = . o E |
|.o .o + S        |
|..++   o .       |
| .+  o.          |
|   oo .+ o       |
|  . ....=        |
+----[SHA256]-----+
[test@test ~]#

2，在该用户的家目录会生成一个.ssh目录，进入该目录，拷贝一份公钥（id_rsa.pub），并命名为 authorized_keys

[test@test ~]# cd .ssh/
[test@test .ssh]# pwd
/home/test/.ssh
[test@test .ssh]# ll
总用量 12
-rw-------. 1 test root 1675 6月  29 17:01 id_rsa
-rw-r--r--. 1 test root  390 6月  29 17:01 id_rsa.pub
-rw-r--r--. 1 test root 1042 6月   6 10:08 known_hosts
[test@test .ssh]#
[test@test .ssh]# cp id_rsa.pub authorized_keys
[test@test .ssh]#

3，在B，C机器的test用户下执行ssh-keygen

4，将 id_rsa，id_rsa.pub，authorized_keys拷贝至B，C机器的/home/test/.ssh下即可（使用root用户拷贝）

[root@test .ssh]# scp authorized_keys id_rsa id_rsa.pub root@10.10.10.1:/home/test/.ssh/

5，测试，切换test用户：su - hdfs，执行ssh test@10.10.10.2

[root@test ~]# su - test
[test@test ~]# 
[test@test ~]# ssh test@10.10.10.1