linux远程免登录设置及取消

在服务器生成密钥

# 生成密钥，可直接回车（3次回车)使用默认参数
ssh-keygen -t rsa

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:NThsaNcK2ITXrGT+Mk09Oyo41TggyGWQvL8pqEG0NVI root@iZuf60hcu5gmej6nes0efhZ
The key's randomart image is:
+---[RSA 3072]----+
|..oE ..o         |
| o.o.++ooo       |
|.++o.==.*.+      |
|oo= o.o+.+o.     |
| o.. . *S  o     |
|.  .  * + o      |
|o   oo + . .     |
|.o oo . .        |
|o .  . .         |
+----[SHA256]-----+

将公钥写入authorized_keys

# 进入目录
cd /root/.ssh/
cat  id_rsa.pub  >> authorized_keys

赋权

chmod 700 /root/.ssh
chmod 600 /root/.ssh/authorized_keys 

在客户端下载公钥

ssh-copy-id root@139.11.11.66

测试，不提示输入密码表示成功

ssh root@139.11.11.66

取消免登录

# 登录服务器
# 打开文件 authorized_keys
vim /root/.ssh/authorized_keys
 	文件内容如下：
	ssh-rsa AAAAB3NzaC1yc2E74AaJB root@worker
	ssh-rsa AAAAB3NzaC1yc2E74AaJB root@worker-103
	将文件中的与你ip对应的哪一行删掉，我这里@……是主机名
vim /root/.ssh/known_hosts
	文件内容如下：
	192.168.182.101 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYlipjNdoiRW8N3A=
	192.168.182.102 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmDMKSpsJSoo=
	192.168.182.143 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbAIbmlzdHAyHgE3KGeVHGAf8=
	将文件中的与你ip对应的哪一行删掉

可能出现的错误

1，/usr/bin/ssh-copy-id: ERROR: failed to open ID file '/root/.pub': No such file or directory

这是本机没有公共密钥的问题，只需要在本机生成一个密钥就行