Ubuntu VNC Setup

Environment

• Ubuntu 18.04 Desktop

Requirements

• sudo apt install tigervnc-standalone-server tigervnc-viewer
• sudo apt install xfce4

Setup

• Put xstartup in ~/.vnc/
• Run vncserver -localhost yes :1
  • Stop it by vncserver -kill :1
• Then you can use your favorite VNC Viewer to connect to localhost:5901 (:1 refers to port 5901)

TODO

• There are still some icon missing.
  • I finally fixed it by tweaking the theme. See https://askubuntu.com/questions/1311713/can-anyone-help-me-with-my-tigervnc-xstartup-script-for-ubuntu-18-04s-gnome-doc

Troubleshooting

• gnome-session --session=ubuntu --debug
• ps aux | grep gnome: See how gdm invoke gnome-session
• man gnome-session
• man gnome-shell
• man gdm3: It mentions /usr/share/xsessions
• apt list --installed | grep gnome
  • gnome-shell-extension-ubuntu-dock
• dbus-daemon
• man vnc.conf
• /etc/vnc.conf
• man vncserver
• man Xsession
• /usr/lib/gdm3/gdm-x-session
• cat /etc/X11/default-display-manager
• vim /etc/X11/Xvnc-session
• vim /etc/X11/Xsession
• /etc/gdm3
• /etc/X11/Xsession.d/20x11-common_process-args
• /etc/X11/Xsession.d/50x11-common_determine-startup
  • In my Ubuntu 18.04, x-session-manager is an alias to /etc/alternatives/x-session-manager (where it eventually point usr/bin/gnome-session)
• env |grep XDG_DATA_DIRS: This enviornment variable will control how the .desktop file are loaded.
• /etc/profile.d/xdg_dirs_desktop_session.sh: This file explains why /usr/share/ubuntu is added in XDG_DATA_DIRS

References

• https://help.ubuntu.com/community/VNC/Servers: I mainly consulted this page

• https://www.cyberciti.biz/faq/install-and-configure-tigervnc-server-on-ubuntu-18-04/

• https://askubuntu.com/questions/648819/couldnt-start-xtightvnc-trying-default-font-path-vncserver

• https://bugzilla.redhat.com/show_bug.cgi?id=1149893: Color profile issue when successfully entering GNOME.

• https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-vnc-on-ubuntu-18-04

• https://www.teknotut.com/en/install-vnc-server-with-gnome-display-on-ubuntu-18-04/

• https://askubuntu.com/questions/1031147/running-vnc-server-on-ubuntu-desktop-18-04-by-creating-new-sessions/1035321#1035321

  • The Gnome session doesn't seem to work on VNC X servers, but an Xvfb will work. The idea is to create an Xvfb for the session and use x11vnc for VNC

• https://askubuntu.com/questions/281177/colours-background-messed-up-in-vnc-viewer: VNC quality.

• https://askubuntu.com/questions/905466/dropbox-icon-not-working-unable-to-create-dbus-session-bus

• https://askubuntu.com/questions/502837/dbus-folder-in-home-folder-belongs-root: ~/.dbus/ folder.

• https://askubuntu.com/questions/281177/colours-background-messed-up-in-vnc-viewer: Change Picture Quality to High.

• https://www.linuxquestions.org/questions/linux-general-1/icons-missing-from-desktop-with-vnc-and-gnome-session-36174/: Icon missing

• https://unix.stackexchange.com/questions/512679/vnc-server-not-showing-icons-in-ubuntu-18-04:

  I suspect the issue is somewhere else that the xstartup. I have tried several different settings there and outcome is always same.
  

• https://www.linuxquestions.org/questions/linux-newbie-8/starting-gnome-session-over-vnc-268828/

• https://askubuntu.com/questions/771124/vnc-ubuntu-14-04-destop-dont-show-menus-icon

• https://askubuntu.com/questions/1209511/what-is-a-ubuntu-gnome-session-and-why-isnt-it-a-systemd-user-session: gnome-session's --session arg; /usr/share/gnome-session/sessions/ubuntu.session

• https://unix.stackexchange.com/questions/345344/difference-between-xorg-and-gnome-kde-xfce: The relation between GNOME and X (aka X11, X Window Systems)

• https://linuxhint.com/how_gnome_starts/

• https://askubuntu.com/questions/971388/few-application-icons-not-appearing-in-ubuntu-dock-after-upgrading-to-ubuntu-17

• https://askubuntu.com/questions/1209511/what-is-a-ubuntu-gnome-session-and-why-isnt-it-a-systemd-user-session: See /usr/share/xsessions/ubuntu.desktop

• https://unix.stackexchange.com/questions/263922/what-is-the-tryexec-field-in-desktop-files: TryExec in .desktop file.

• http://manpages.ubuntu.com/manpages/bionic/man1/dbus-launch.1.html: dbus-launch --exit-with-session gnome-session

• TigerVNC/tigervnc#1131: Almost the same error messages as me!

• https://stackoverflow.com/questions/17251293/what-is-the-relationship-between-x11-and-gnome: The relationship between GNOME and X

• https://askubuntu.com/questions/1033004/18-04-how-to-get-wayland-back-after-upgrade-to-18-04: /etc/gdm3/custom.conf /etc/gdm3/Xsession

• https://specifications.freedesktop.org/desktop-entry-spec/latest/: .desktop specification

• https://wiki.archlinux.org/index.php/desktop_entries

• https://specifications.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html

  • See Icon Lookup
  • See /usr/share/icons/hicolor/index.theme

• https://wiki.archlinux.org/index.php/TigerVNC: Arch Linux doc never fails me.

• https://wiki.archlinux.org/index.php/GNOME#GNOME_Shell_themes

• https://gitlab.gnome.org/GNOME/gdm/blob/master/daemon/gdm-x-session.c: gdm-x-session

• https://c-nergy.be/blog/?p=12073

• https://unix.stackexchange.com/questions/417906/authentication-is-required-to-create-a-color-profile: Color profile issue

• https://askubuntu.com/questions/64283/custom-application-icons-not-displaying: Icon cache: gtk-update-icon-cache

• https://itsfoss.com/gnome-tweak-tool/: apt install gnome-tweaks

• https://askubuntu.com/questions/779645/ubuntu-software-icon: /usr/share/ubuntu/applications/org.gnome.Software.desktop and /usr/share/applications/org.gnome.Software.desktop: I totally not understand why there are two desktop file....

• https://askubuntu.com/questions/1312020/can-someone-explain-why-there-exist-two-org-gnome-software-desktop-files-which: The question I ask. I found this related to XDG_DATA_DIRS.

• https://unix.stackexchange.com/questions/471327/whats-the-right-way-to-add-directories-to-xdg-data-dirs: XDG_DATA_DIRS

• https://gitlab.gnome.org/GNOME/gdm/-/blob/97ca4b1268e78a21041d9fda9512b892ce344d92/daemon/gdm-session.c#L2631-2641: DESKTOP_SESSION is set in this line. However, my ad-hoc xstartup was not invoked by gdm-* related processes. For more information, please see gdm_session_start_session function in that link. (There is a set_up_session_environment function).