NVE：无法在 NVE 上启动 SSH 服务

nve:~ # systemctl start sshd.service
Job for sshd.service failed because the control process exited with error code. See "systemctl status sshd.service" and "journalctl -xe" for details.

nve:~ # systemctl status sshd.service
● sshd.service - OpenSSH Daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: disabled)
   Active: failed (Result: start-limit) since Tue 2021-04-27 15:43:49 EDT; 17s ago
  Process: 6576 ExecStart=/usr/sbin/sshd -D $SSHD_OPTS (code=exited, status=0/SUCCESS)
  Process: 12164 ExecStartPre=/usr/sbin/sshd -t $SSHD_OPTS (code=exited, status=255)
  Process: 12161 ExecStartPre=/usr/sbin/sshd-gen-keys-start (code=exited, status=0/SUCCESS)
 Main PID: 6576 (code=exited, status=0/SUCCESS)
    Tasks: 6
   CGroup: /system.slice/sshd.service
           ├─11434 sshd: admin@pts/0
           ├─11438 -bash
           ├─11939 sudo su
           ├─11942 su
           ├─11943 bash
           └─12169 systemctl status sshd.service

Apr 27 15:43:48 nve systemd[1]: Failed to start OpenSSH Daemon.
Apr 27 15:43:48 nve systemd[1]: sshd.service: Unit entered failed state.
Apr 27 15:43:48 nve systemd[1]: sshd.service: Failed with result 'exit-code'.
Apr 27 15:43:49 nve systemd[1]: sshd.service: Service RestartSec=100ms expired, scheduling restart.
Apr 27 15:43:49 nve systemd[1]: Stopped OpenSSH Daemon.
Apr 27 15:43:49 nve systemd[1]: sshd.service: Start request repeated too quickly.
Apr 27 15:43:49 nve systemd[1]: Failed to start OpenSSH Daemon.
Apr 27 15:43:49 nve systemd[1]: sshd.service: Unit entered failed state.
Apr 27 15:43:49 nve systemd[1]: sshd.service: Failed with result 'start-limit'.

nve:~ # tail -n 30 /var/log/messages | grep ssh
Apr 27 15:43:48 nve systemd[1]: sshd.service: Service RestartSec=100ms expired, scheduling restart.
Apr 27 15:43:48 nve sshd-gen-keys-start[12161]: Checking for missing server keys in /etc/ssh
Apr 27 15:43:48 nve ssh-keygen[12162]: OWB:ERROR:BSAFELIB:func(112):reason(113):b_dsa.c:112
Apr 27 15:43:48 nve sshd-gen-keys-start[12161]: ssh-keygen: generating new host keys: DSA key_generate failed: error in libcrypto
Apr 27 15:43:48 nve sshd[12164]: /etc/ssh/sshd_config line 171: Directive 'kexalgorithms' is not allowed within a Match block
Apr 27 15:43:48 nve systemd[1]: sshd.service: Control process exited, code=exited status=255
Apr 27 15:43:48 nve systemd[1]: sshd.service: Unit entered failed state.
Apr 27 15:43:48 nve systemd[1]: sshd.service: Failed with result 'exit-code'.
Apr 27 15:43:49 nve systemd[1]: sshd.service: Service RestartSec=100ms expired, scheduling restart.
Apr 27 15:43:49 nve systemd[1]: sshd.service: Start request repeated too quickly.
Apr 27 15:43:49 nve systemd[1]: sshd.service: Unit entered failed state.
Apr 27 15:43:49 nve systemd[1]: sshd.service: Failed with result 'start-limit'.

NVE /etc/ssh/sshd_config 文件包含一个 kexalgorithms 条目，在以前的 NVE 升级期间未删除该条目。 

nve:~ # cat /etc/ssh/sshd_config | grep -b2 kexalgorithms
Match Address ::1,127.0.0.1,127.0.0.1,127.0.0.2,::1,10.0.0.3,fe80::250:56ff:febb:58e7
   PermitRootLogin yes
kexalgorithms diffie-hellman-group-exchange-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,curve25519-sha256@libssh.org

1. 从 vSphere Web Client 中，打开与 NVE 的远程控制台会话
2. 使用 root 用户向 NVE 进行身份验证
3. 使用文本编辑器打开 /etc/ssh/sshd_config 文件： vi /etc/ssh/sshd_config
4. 删除或注释掉 kexalgorithms 行
5. 保存对 /etc/ssh/sshd_config文件的更改。
6. 启动 SSHD 服务： systemctl start sshd.service