Linux physical session issues

[hauchong]

Hi,

Test environment:

- Ubuntu 20.04 physical box installed with viewagent 1-8.4.1-20664218 and vadc plugin 2111.1-8.4.1-20664218

- Windows 10 with Horizon client 2209, 8.7.0 (20649873)

- Multi-session mode enabled during Horizon agent (viewagent) installation

Test items:

1. Horizon client attempt to remote control the physical session (the desktop session displayed to physical monitor) of Ubuntu box.

2. User A logged in physical session (sitting in front of the Ubuntu box), then launch a virtual session by same user account with Horizon client from Windows box.

3. User A logged in physical session (sitting in front of the Ubuntu box), then launch a virtual session by user B with Horizon client from Windows box.

4. User A launched a virtual session with Horizon client from Windows box, then login physical session by same user account (sitting in front of the Ubuntu box).

5. User A launched a virtual session with Horizon client from Windows box, then login physical session by user B (sitting in front of the Ubuntu box).

Test result:

1. Horizon client cannot control the physical session, it can launch a virtual session only.

2. Blank screen with cursor displayed to the virtual session by Horizon client,

some applications (i.e. gnome-terminal and other gnome-* desktop apps) opened in physical session are displayed to the virtual session.

The blank screen desktop in virtual session close when user logged out from physical session.

Horizon client is able to open virtual session when attempt to launch again (no user logged in to physical session)

3. Both physical session and virtual session are launched successfully.

4. Blank screen with cursor displayed to the physical monitor,

some applications (i.e. gnome-terminal and other gnome-* desktop apps) opened in virtual session are displayed to the physical monitor.

The blank screen in physical monitor turn back to Ubuntu GUI login screen when user logged out (not disconnect) from virtual session.

5. Both virtual session and physical session are launched successfully.

I tried to set both Desktop.displayNumberMin=1 and Desktop.displayNumberMax=1, but it still doesn't work. (it seems GDM/Xorg detected display number 1 already taken, so it started with display number 2 when bootup)

That is fine if I play with virtual session only,

I knew Linux physical box is not officially supported,

just want to share my experience and see if anyone has workaround/solution for that?

Can it control physical session?

Can user login to the Ubuntu box physically and launch another virtual session simultaneously?

Thank you.

[hauchong]

Interesting, I can login to both physical session and virtual session simultaneously with same user account, if I do the test with RHEL 7.10.

[yanchaozhang]

Thank you Hauchong for sharing your experience with linux agent VADC 🙂

The support for physical PC is on the roadmap, maybe this summer ?

under the hood, we create new session(new X) for remote(virtual) login, and leave console session(X:0) untouched, so

- there is no way to control 'physical session' remotely via horizon client, (until further configuration applied, I'm checking now ...)

- and the behavior of login as both console(physical) session and remote session with the same user is undefined, but different should be OK.

please upload logs for the failure case of different user, we can have furhter analysis based on that

[hauchong]

Hi yanchaozhang,

"- and the behavior of login as both console(physical) session and remote session with the same user is undefined, but different should be OK."

You're correct, that's okay with different users (although horizon client unable to control the physical console).

With same user account, Ubuntu 20.04 and RHEL7 have different outcomes.

Ubuntu 20.04:
The later session doesn't takeover the existing session, just stuck and displayed a blank screen after login. 

RHEL 7:
The later session doesn't takeover the existing session, it launches a separate desktop session.

[yanchaozhang]

Thank you hauchong for pointing out the differences between ubuntu2004 and RHEL7 🙂

We had a discussion within team, seems the difference(with same user) is distribution specific which is hard to make them consistent with our linux agent product, we also goooogled a lot on this topic and found the following interesting links:

https://www.reddit.com/r/gnome/comments/4cqymo/is_it_possible_to_get_multiple_sessions_for_the/

https://superuser.com/questions/1657933/gdm-two-independent-login-screens

I copy part of them from reddit link here for your convenience:

"I don't think it is possible, but even if it was, a lot of applications don't work well when running in multiple sessions of the same user. Applications usually assume they are the only ones writing to the files they have open. Some applications try to ensure they are the only ones using those files by checking if another instance is already running on the sessions dbus session bus. If you have multiple sessions, you have multiple dbus session buses, and that check would fail. This means that multiple instances of an application might try to write to the same files, which in the worst case could result in some data loss."