[X2go-Dev] Status load balancing in X2go, and alternatives

[John A. Sullivan III]

On Mon, 2011-09-19 at 22:38 +0200, Paul van der Vlis wrote:
> Op 16-09-11 07:31, John A. Sullivan III schreef:
> 
> > We are building that scale of environment.  For better or worse, we have
> > been so overrun with consulting work that we are way behind where we
> > hoped to be in our X2Go build but we have taken a different approach.
> > 
> > We integrated X2Go and Linux-VServer.  Each user has a dedicated system
> > (great for things like non-repudiation) but the extra resource
> > requirements are minimal.  
> 
> Even with RAM? I think every user needs his own OpenOffice in RAM, so
> you need much more RAM this way. But maybe I'm wrong.
Nope - with the impressive hashification feature of VServer there is
only a single copy of the binary in memory.  So if I have four hundred
identical systems, I consume the disk space of one system and the memory
footprint of one system (not quite realistic as it will have more
binaries loaded than a single user would likely use but 300 users may
have a single copy of OO in memory, 275 may have a single copy of
Firefox, 50 a single copy of GIMP, etc., and the user data may consume
considerably more than the binary (especially with massive Firefox
memory leaks as we sometimes see).
> 
> We have been thinking about using Linux containers. But we decide first
> to work with some shared virtual machines because we have more
> experience with that.  http://lxc.sourceforge.net/
> 
> > We then moved the x2gocleansession
> > processing to the VServer host so there is only one daemon running every
> > five seconds instead of hundreds.
> > 
> > We also adapted the database to use schemas - one per user, and triggers
> > for coordinating individual user changes with the master database used
> > by x2gocleansession and other reporting utilities we created.  Thus, we
> > have a single database for all those potentially hundreds of X2Go
> > servers.
> > 
> > Finally, we adapted the x2go printing so that we could use a single CUPS
> > server for all X2Go users and not have hundreds of instances of CUPS
> > running.
> > 
> > So far it has scaled very nicely but I am way behind in seeing how we
> > would make the same changes to 3.99 - John
> 
> Does every user have it's own IP on the server?
Each user has their own VM and thus their own IP and, since the VMs do
not have root capability or system level privileges, they cannot change
their IPs (or do things like sniff packets).  This works really nicely
when we overlay Firepiping on the system (http://iscs.sourceforge.net)
so that we can granularly restrict what packets users can send on the
network to shut down any snooping or attempts at escalating privileges -
John
> 
> With regards,
> Paul.
> 
>