tigervnc on nfs mounted home directory

[Puneet Singh]

Hi , 
We are working to provide VNC sessions in an environment where the /home directory is NFS mounted on two servers: one running CentOS 7 (Server A) and the other running RHEL 8 (Server B). 

Here's our VNC session setup:

1. Configure session and geometry information in ~/.vnc/config:
    PlainUsers=userA
    session=xfce
    geometry=1920x1080
   

2. Set up user and port information in /etc/tigervnc/vncserver.users:
    :8=userA
   

3. Start the systemd service:
    systemctl start vncserver@:8
   

This setup allows users to run two sessions simultaneously across different hosts, supporting both XFCE and GNOME sessions on each server. Both GNOME and XFCE use the /home directory to store configuration data. We are concerned about potential issues that might arise from CentOS 7 and RHEL 8 sharing the same /home directory for settings and configurations.

Can you provide insights into how safe it is to have RHEL 8 and CentOS 7 use a shared /home directory? What major issues might we encounter?

and are there any recommendations to make it a bit safer?
like if we use GNOME on Server A and XFCE on server B then i beleive that there is less chance of setting conflict.

NOTE: RHEL 8 is new addition to the environment, so we do have settings from Centos 6 and Centos 7 gnome/xfce sessions under /home. But still, RHEL8 based vnc sessions are starting up without issues so far.

Please advice.

Regards,

[Pierre Ossman]

On 19/07/2024 17:41, Puneet Singh wrote:
>
> Can you provide insights into how safe it is to have RHEL 8 and CentOS 7
> use a shared /home directory? What major issues might we encounter?
>
> and are there any recommendations to make it a bit safer?
> like if we use GNOME on Server A and XFCE on server B then i beleive that
> there is less chance of setting conflict.
>

These are really GNOME/Xfce questions, rather than TigerVNC. But we have
some experience with this.

Unfortunately, the answer is that stuff can misbehave with a shared home
directory. E.g. dconf (the configuration storage for GNOME) is not safe
to use on NFS by default. We've seen settings getting randomly lost. It
can be reconfigured to be NFS safe, though.

Some applications are better and detect the situation. E.g. Firefox,
that will simply refuse to start when it detects that the profile is in
use from another machine.

Using different desktop environments probably lessens the risk. But Xfce
is built on Gtk and other GNOME technologies. So there is probably still
some overlap. And that says nothing about the applications the users
might use.

I'm afraid I don't have any good suggestions except "don't do that". The
Linux world isn't currently too focused on multiple session support, no
matter the form. :/

Perhaps avoid sharing the entire home directory and just things like
documents?

Regards,
--
Pierre Ossman Software Development
Cendio AB http://cendio.com
Teknikringen 8 http://twitter.com/ThinLinc
583 30 Linköping http://facebook.com/ThinLinc
Phone: +46-13-214600

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