Does the virt-manager port have additional requirements?

[Ralph Seichter]

Hello.

I have installed the virt-manager port on macOS Catalina:

  The following ports are currently installed:
  virt-manager @2.1.0_0 (active)

Alas, on launch I only get an error message stating that the display
can't be opened.

  → virt-manager -c 'qemu+ssh://user@host/system?socket=/run/libvirt/libvirt-sock' --debug
  [Sa, 30 Mai 2020 00:59:11 virt-manager 12280] DEBUG (cli:203) Launched with command line: /opt/local/Library/Frameworks/Python.framework/Versions/3.7/share/virt-manager/virt-manager -c qemu+ssh://user@host/system?socket=/run/libvirt/libvirt-sock --debug
  [Sa, 30 Mai 2020 00:59:11 virt-manager 12280] DEBUG (virt-manager:176) virt-manager version: 2.1.0
  [Sa, 30 Mai 2020 00:59:11 virt-manager 12280] DEBUG (virt-manager:177) virtManager import: <module 'virtManager' from '/opt/local/Library/Frameworks/Python.framework/Versions/3.7/share/virt-manager/virtManager/__init__.py'>

  (virt-manager:12280): Gtk-WARNING **: 00:59:11.316: cannot open display:

I have made sure to enable ForwardX11 and ForwardX11 in my SSH client
config, and X11Forwarding in the SSH-Daemon config. I can also use the
same connection URL successfully with "virsh".

What am I missing? Do I need to install a separate X-Server on my Mac?

-Ralph