记录一次sshd服务启动失败

时间:2022-10-27 07:08:44

问题描述:

服务器开机之后发现无法通过远程连接服务器终端,但是服务器并未宕机,于是考虑到sshd服务出现异常

解决思路:

  1. 查看服务器sshd服务运行情况

    [root@haha-main-130 var]# systemctl status sshd -l
    ● sshd.service - OpenSSH server daemon
       Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
       Active: activating (auto-restart) (Result: exit-code) since 三 2022-10-26 10:02:14 EDT; 29s ago
         Docs: man:sshd(8)
               man:sshd_config(5)
      Process: 2089 ExecStart=/usr/sbin/sshd -D $OPTIONS (code=exited, status=255)
     Main PID: 2089 (code=exited, status=255)
    
    10月 26 10:02:14 haha-main-130 systemd[1]: sshd.service: main process exited, code=exited, status=255/n/a
    10月 26 10:02:14 haha-main-130 systemd[1]: Failed to start OpenSSH server daemon.
    10月 26 10:02:14 haha-main-130 systemd[1]: Unit sshd.service entered failed state.
    10月 26 10:02:14 haha-main-130 systemd[1]: sshd.service failed.
    

    服务并未正常启动

  2. 定位问题详细信息

    [root@haha-main-130 var]# sshd -t
    /var/empty/sshd must be owned by root and not group or world-writable.
    

    可以看到输出的信息表示:/var/empty/sshd必须是root用户所有,而不是root用户组或全部人都可写入

  3. 问题处理

    查看/var/empty/sshd目录权限

    [root@haha-main-130 var]# ll /var/empty
    总用量 0
    drwxrwxrwx. 2 root root 6 8月   8 2019 sshd
    

    由于之前调试原因,将/var目录所有的权限都调整成了777,所以造成sshd无法启动

  4. 修改目录权限

    [root@haha-main-130 var]# chmod -Rf 755 /var/empty/sshd/
    [root@haha-main-130 var]# ll /var/empty
    总用量 0
    drwxr-xr-x. 2 root root 6 8月   8 2019 sshd
    
  5. 重新启动服务

    [root@haha-main-130 var]# systemctl restart sshd
    [root@haha-main-130 var]# systemctl status sshd
    ● sshd.service - OpenSSH server daemon
       Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
       Active: active (running) since 三 2022-10-26 10:13:11 EDT; 6s ago
         Docs: man:sshd(8)
               man:sshd_config(5)
     Main PID: 2150 (sshd)
       CGroup: /system.slice/sshd.service
               └─2150 /usr/sbin/sshd -D
    
    10月 26 10:13:11 haha-main-130 sshd[2150]: Server listening on 0.0.0.0 port 22.
    10月 26 10:13:11 haha-main-130 systemd[1]: Stopped OpenSSH server daemon.
    10月 26 10:13:11 haha-main-130 sshd[2150]: Server listening on :: port 22.
    10月 26 10:13:11 haha-main-130 systemd[1]: Starting OpenSSH server daemon...
    10月 26 10:13:11 haha-main-130 systemd[1]: Started OpenSSH server daemon.
    Hint: Some lines were ellipsized, use -l to show in full.
    

    sshd服务可以正常启动