is there a recommended desktop-sharing app for sysadmin access to headless servers that must run GUI applications? would xrdp be a suitable solution?
nxserver is overkill (and newer free versions are slowwww) but what I require is a single virtual desktop session that automatically starts on machine reboot and can then be joined by one or more system admins who can share this only one persistent session as a shared desktop and has client software for Linux, Mac and Windows.
It seems a very workable solution is vncserver running xfce4 and accessed with ssh tunnels -- the bit remaining to implement is to have the server auto-login with the admin account so the vncserver session can be bootstrapped, and from there xfce4 can include the necessary apps to auto-start.
since aws server access requires the pem certificate (ssh -i) the tunneling solution works well with ssh -L 5901:localhost:5901 -N -f -l <user> <serverIP>
many thanks to Digital Ocean for continuing to maintain their vnc/xfce4 guide at https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-vnc-on-ubuntu-16-04