Being desktops I assume Xorg is running on those machines.
In that case you can simply use VNC.
Install tigervnc-server on all your servers, and tigervnc on your client and set them up with local users (although, again, being desktops you probably already have a user that starts X)
this will allow you to connect to all your machines while JUST using the network instead of dealing with additional cables connect/disconnect.
IF you don't have Xorg running, then it's not necessary for you to do all this, via SSH you can manage your machine easily.
ssh user@host -c "systemctl start httpd.service"
You can even work with additional machines with Systemctl (since you speak of CentOS7)
systemctl --host user@host start httpd.service
These both work via ssh starting
httpd.service on the host
host with user
Also with systemd-journal-remote you can share journal entries between hosts, but it's a bit more complex to set up, with
--listen-http you can passively wait for entries and then
-o output them somewhere on your local machine.
RHEL Documentation on these subjects, FYI:
VNC Client & Server from scratch: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/ch-tigervnc#sec-terminating-vnc-session
VNC Existing Server: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/sec-vnc-sharing-an-existing-desktop
VNC Existing Client: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/sec-vnc-viewer