centos8 ssh登录设置-摩杜云开发者社区

一般来说，从阿里云、centos官方下载的centos镜像都会预先打包好很多工具。像ssh登录这种服务已经做好，不需要用户去关注。但是也有一些小公司打包的镜像是相对纯净的发行包。
如果是已经可以用账户和密码登录，则无需查看本文内容亦可。

ssh(安全外壳协议)是一种加密通讯协议，主要用于安全登录服务。运行模式是c/s结构。
sshd是服务器，运行在linux服务器上面（一般安装后都是开机启动）。xshell这种pc客户端是封装了ssh的客户端协议。

在centos安装sshd服务：
0、Ip设置

root@node1:~# cat /etc/netplan/00-installer-config.yaml 
# This is the network config written by 'subiquity'
network:
  ethernets:
    enp0s3:
      dhcp4: no
      dhcp6: no
      addresses: [192.168.1.150/24]
      gateway4: 192.168.1.1
      nameservers:
              addresses: [114.114.114.114, 8.8.8.8]
  version: 2
root@node1:~#

1、查看SSH是否安装

输入命令：rpm -qa | grep ssh
　　注：若没安装SSH则可输入：yum install openssh-server安装

[centos@skycloud-1 ~]$ rpm -qa | grep ssh
openssh-server-7.4p1-16.el7.x86_64
libssh2-1.4.3-12.el7_6.3.x86_64
openssh-7.4p1-16.el7.x86_64
openssh-clients-7.4p1-16.el7.x86_64
[centos@skycloud-1 ~]$

2、启动SSH服务

　　输入命令：systemctl restart  sshd 重启SSH服务。
　　命令：systemctl start sshd 启动服务 |  命令：systemctl stop sshd 停止服务 
　　重启后可输入：netstat -antp | grep sshd 查看是否启动22端口（可略）。

[centos@skycloud-1 ~]$ sudo systemctl restart  sshd
[centos@skycloud-1 ~]$ sudo netstat -antp | grep sshd
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      20090/sshd          
tcp        0      0 184.105.242.157:22      43.249.31.35:49858      ESTABLISHED 10021/sshd: centos  
tcp        0    140 184.105.242.157:22      116.7.11.155:51234      ESTABLISHED 10054/sshd: centos  
tcp6       0      0 :::22                   :::*                    LISTEN      20090/sshd          
[centos@skycloud-1 ~]$

3、设置sshd开机启动

[centos@skycloud-1 ~]$ sudo systemctl enable sshd
[centos@skycloud-1 ~]$

比较严格的生产环境中，一般都是使用私钥来登录centos节点。

例如在一个centos客户端节点，通过ssh和私钥来登录目标节点：

[root@bogon tmp]# chmod 400 myid.pem 
[root@bogon tmp]# ssh -i myid.pem centos@49.10.22.39
The authenticity of host '49.10.22.39(49.10.22.39)' can't be established.
ECDSA key fingerprint is SHA256:bsqhV1RxWy+TPwSqTRdgxeyIorK1qEqazkPH3/V8kTE.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '49.10.22.39' (ECDSA) to the list of known hosts.
Last login: Thu Feb 27 05:06:22 2020 from 43.249.31.35
[centos@skycloud-1 ~]$ ifconfig 
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 49.10.22.39  netmask 255.255.255.224  broadcast 184.105.242.159
        inet6 fe80::f816:3eff:fe9b:4f9f  prefixlen 64  scopeid 0x20<link>
        ether fa:16:3e:9b:4f:9f  txqueuelen 1000  (Ethernet)
        RX packets 2029  bytes 200127 (195.4 KiB)
        RX errors 0  dropped 6  overruns 0  frame 0
        TX packets 431  bytes 54139 (52.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 6  bytes 416 (416.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 6  bytes 416 (416.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[centos@skycloud-1 ~]$

对于一般的企业来说，实用账户密码来登录。

4、设置可以密码登录centos

vim /etc/ssh/sshd_config 保证下面两个配置是如下设置：

#允许使用密码登录
PasswordAuthentication yes
#允许root认证登录
PermitRootLogin yes

2、重启sshd

systemctl restart sshd

3、设置免密登录（将客户端节点的公钥，拷贝到目标节点并被目标节点注册）

ssh-kengen
ssh-copy-id -i .ssh/id_rsa.pub  root@49.10.22.39