I am no RPM pro, so I am not sure what is where in CentOS 7.
The package libappindicator is used to show the tray icon on the user desktop. If you do not plan on using the desktop, you can ignore it. If you do not install it, it should work anyway, using the GTK app indicator, which may or may not be hidden by default.
I’m actually still trying to get a VM for Centos 7 installed so I could test…I chose minimal (kept getting errors downloading the full ISO) then had a to wait for Gnome to install… but I’m sure it will be great once I’m done.
Actually, I’m running CentOS 7 on a physical box inside of which I’m running a CentOS 7 instance in a VM (VirtualBox) that contains only what’s needed to run my mail server. (Maybe someday I’ll switch to Docker for this but I don’t care enough about that)
The whole point is to be have a backup of the VM (independently of backing up the data inside it, which is what I’m doing now) so that if the hardware dies I can just bring up a new already configured turnkey mailserver on another machine and just restore the mail from Duplicati
I don’t know about getting the service running, but here’s what worked for me to install the Duplicati tray icon from the terminal on a fresh install of CentOS 7 (Minimal):
Run sudo yum install epel-release
Note: I got a message about not being in the sudoers file so needed to do a full su to continue.
Run wget https://updates.duplicati.com/beta/duplicati-22.214.171.124-126.96.36.199_beta_20170801.noarch.rpm
Run sudo yum --nogpgcheck localinstall duplicati-188.8.131.52-184.108.40.206_beta_20170801.noarch.rpm
Duplicati was then visible in the GUI under “Aplications -> System Tools -> Duplicati”
Note: I’m not used to the Centos 7 graphical shell so didn’t realize the Tray Icon actually is in a hidden-by-default ‘ribbon’.