There's more...

If you're interested in seeing both servers running, there's a few methods of doing so.

On centos2, start with ss:

[vagrant@centos2 ~]$ sudo ss -tna -4
State       Recv-Q Send-Q     Local Address:Port                    Peer Address:Port              
LISTEN      0      128                    *:2020                               *:*                  
LISTEN      0      128                    *:111                                *:*                  
LISTEN      0      128                    *:22                                 *:*                  
LISTEN      0      100            127.0.0.1:25                                 *:*                  
ESTAB       0      0              10.0.2.15:22                          10.0.2.2:59594 

We can also use systemd's built-in commands:

[vagrant@centos2 ~]$ PAGER= systemctl | grep sshd
  sshd.service                                                                             loaded active running   OpenSSH server daemon
  sshd_2020.service                                                                        loaded active running   OpenSSH server daemon on port 2020

And lastly, we can use good old ps:

[vagrant@centos2 ~]$ ps aux | grep sshd
root       856  0.0  0.8 112796  4288 ?        Ss   16:52   0:00 /usr/sbin/sshd -D -u0 -f /etc/ssh/sshd_config_2020
root       858  0.0  0.8 112796  4292 ?        Ss   16:52   0:00 /usr/sbin/sshd -D -u0