[FreeNX-kNX] freenx and real X-session

[Mario Becroft]

Simon Gao <gao at schrodinger.com> writes:

> Thanks this is very helpful. Can you give an example about configuring nx 
> server to allow client see the list of existing sessions? And how to configure 
> nxclient to let user see such list?

I have not played with this a great deal, but the way I understand it:

When you login to an nxagent session, if you have no other sessions, one
will be created. If you already have more than one session running, then
nxclient presents a list where you can choose to resume a session, or
create a new session. (It also allows you to terminate an existing
session.) In my experience, if you have only one session and it matches
the geometry of your screen, it will automatically be resumed without
presenting a list.

By default users may create up to 200 sessions. (You can change this
limit by adjusting SESSION_USER_LIMIT in node.conf.)

Other relevant parameters are:

ENABLE_PERSISTENT_SESSION/DISABLE_PERSISTENT_SESSION: lets you control
who is allowed to suspend sessions

ENABLE_SHOW_RUNNING_SESSIONS: by default on, if turned off then you
cannot resume a session that is still running somewhere else

ENABLE_AUTORECONNECT: I have not got my head around this one. In my
experience, even with this set to 0, it will automatically resume your
session if you have only one session and the geometry of the screen
matches your client. Perhaps turning this one enables automatically
resuming even if the geometry differs.

If you intend to suspend/resume sessions from various hosts, you may
encounter a problem where you cannot resume a session (the session is
listed, but the resume button is disabled). This occurs if the depth or
presence of RENDER extension is mismatched between the session and your
client. Unfortunately, there is currently no way of resuming a session
on a screen of different depth. This has been a major problem for me;
the only workaround is to ensure all your clients have the same screen
depth. Fixing this looks non-trivial; nomachine say they plan to do it,
but I suspect not for a while. Note that resuming on a screen of
different geometry should not be a problem.

In my case I want to make it easy for users to have just one session
that they always leave running, and just suspend and resume. Therefore I
set SESSION_USER_LIMIT to 1, and this ensures that users can't
accidentally confuse themselves by starting multiple sessions. When they
login to nxclient, it automatically starts a session if they don't have
one, or resumes their session if they already have one
suspended/running, which makes the whole thing very simple for users.

-- 
Mario Becroft <mb at gem.win.co.nz>