Mailing List Archive

Steve wrote:
>
> Greetings all,
>
> I already have a 3 node NAT compute cluster running telnet, rlogin and ssh.
>
> I am looking to provide XDMCP access to the linux real-servers in the
> cluster as well as the telnet and ssh connections. Has anybody tried this
> and do you think it is even possible..

don't know anything about XDMCP. UDP (eg DNS and NTP) work fine with LVS.

Any comments / suggestions welcome,
> I have just started looking to the configuration details for XDMCP, and
> which ports it uses (177 UDP). But I am yet to have any success in
> clustering it.

if XDMCP is a single port UDP service, I would expect that LVS would be fine.

Joe

--
Joseph Mack PhD, Senior Systems Engineer, Lockheed Martin
contractor to the National Environmental Supercomputer Center,
mailto:mack.joseph@epa.gov ph# 919-541-0007, RTP, NC, USA

Hello,

On Tue, 13 Mar 2001, Steve wrote:

> Greetings all,
>
> I already have a 3 node NAT compute cluster running telnet, rlogin and ssh.
>
> I am looking to provide XDMCP access to the linux real-servers in the
> cluster as well as the telnet and ssh connections. Has anybody tried this
> and do you think it is even possible.. Any comments / suggestions welcome,
> I have just started looking to the configuration details for XDMCP, and
> which ports it uses (177 UDP). But I am yet to have any success in
> clustering it.

What do you want exactly? To make sure the indirect queries
always work (by providing high availability for the indirect
queries)? May be if you hit the VIP:177 with these indirect queries
you can then select the real X client. May be you can -broadcast
to all hosts in the LAN without using LVS? You can even use software
that can use a list with hosts to receive the broadcast message from
your X servers, in your case the hosts you try to use as XDMCP
real servers. I assume these broadcast XDMCP capabilities can help you
without using LVS?

> Please note that I do have a box up and running that I can connect directly
> to.. It's just clustering it that I have the problem with :)

I assume you have more hosts :) What kind of problems?

> Thanks,
>
>
> Steve.


Regards

--
Julian Anastasov <ja@ssi.bg>

At 01:12 16/03/2001 +0000, you wrote:

> What do you want exactly? To make sure the indirect queries
>always work (by providing high availability for the indirect
>queries)? May be if you hit the VIP:177 with these indirect queries
>you can then select the real X client. May be you can -broadcast
>to all hosts in the LAN without using LVS? You can even use software
>that can use a list with hosts to receive the broadcast message from
>your X servers, in your case the hosts you try to use as XDMCP
>real servers. I assume these broadcast XDMCP capabilities can help you
>without using LVS?
>
> > Please note that I do have a box up and running that I can connect directly
> > to.. It's just clustering it that I have the problem with :)
>
> I assume you have more hosts :) What kind of problems?

The real-servers in the cluster are very powerful boxes (well compared with
the lab machines anyway) as all three real-servers are dual Pentium III -
800Mhz with 512MB ram and Ultra-wide SCSI hardisks (nice toys!)

In the computer lab we run 50% linux 50% windows2000, The aim of putting
XDMCP onto the cluster would be to take advantage of the nice fast boxes to
provide remote X sessions to the people using the windows machines. I would
like it clustered as we already have the cluster, and it is powerful enough
to deal with the extra load.

Additionally we can then provide a shortcut on the desktop of the windows
machines which pops up the XDMCP machine selection window (using exceed)
and people can just click on the only machine there, and get a connection.
(otherwise the poor undergraduates will all get confused, or all use the
top box which will probably be some pathetic P2-233 and it will die
horribly from the extra load)

The real problem is more getting X sessions balanced across the servers
(I'm not even sure if this is possible), as if there wasn't XDMCP we could
always create a X session that only connected to the cluster.

This whole idea is to try and cater for the wider problem which is whatever
the operating system balance in the lab, people always complain that there
are either not enough linux or not enough windows machines :).


> > Thanks,
> >
> >
> > Steve.
>
>
>Regards
>
>--
>Julian Anastasov <ja@ssi.bg>
>
>
>_______________________________________________
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>Send requests to lvs-users-request@LinuxVirtualServer.org
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Steve.

----------------------------------------------------------------------------
Before you criticize someone, walk a mile in his shoes. That way, if he gets
angry, he'll be a mile away - and barefoot.

Hello,

On Fri, 16 Mar 2001, Steve wrote:

> At 01:12 16/03/2001 +0000, you wrote:
>
> > What do you want exactly? To make sure the indirect queries
> >always work (by providing high availability for the indirect
> >queries)? May be if you hit the VIP:177 with these indirect queries
> >you can then select the real X client. May be you can -broadcast
> >to all hosts in the LAN without using LVS? You can even use software
> >that can use a list with hosts to receive the broadcast message from
> >your X servers, in your case the hosts you try to use as XDMCP
> >real servers. I assume these broadcast XDMCP capabilities can help you
> >without using LVS?
> >
> > > Please note that I do have a box up and running that I can connect directly
> > > to.. It's just clustering it that I have the problem with :)
> >
> > I assume you have more hosts :) What kind of problems?
>
> The real-servers in the cluster are very powerful boxes (well compared with
> the lab machines anyway) as all three real-servers are dual Pentium III -
> 800Mhz with 512MB ram and Ultra-wide SCSI hardisks (nice toys!)
>
> In the computer lab we run 50% linux 50% windows2000, The aim of putting
> XDMCP onto the cluster would be to take advantage of the nice fast boxes to
> provide remote X sessions to the people using the windows machines. I would
> like it clustered as we already have the cluster, and it is powerful enough
> to deal with the extra load.
>
> Additionally we can then provide a shortcut on the desktop of the windows
> machines which pops up the XDMCP machine selection window (using exceed)
> and people can just click on the only machine there, and get a connection.
> (otherwise the poor undergraduates will all get confused, or all use the
> top box which will probably be some pathetic P2-233 and it will die
> horribly from the extra load)
>
> The real problem is more getting X sessions balanced across the servers
> (I'm not even sure if this is possible), as if there wasn't XDMCP we could
> always create a X session that only connected to the cluster.

May be you need a new chooser (probably guarded from LVS) that
will allow the client to select only one X Windows client host after
deciding which is the least loaded one. The way XDMCP is working allows
the first who replies for broadcast to serve the X session for the
X server. But I have never tried balancing XDMCP. May be there is
something already invented. If you want LVS to work like a chooser
may be someone must write such scheduler that will reply the indirect
queries and will allow the X server to select the least loaded X
client that is willing to manage the session. May be the health checking
software must perform the forward queries to the real servers to
determine whether they are willing to manage. Not sure, may be the
things can be more complex because it needs talking UDP but LVS does
not generate UDP packets/replies.

> This whole idea is to try and cater for the wider problem which is whatever
> the operating system balance in the lab, people always complain that there
> are either not enough linux or not enough windows machines :).
>
>
> > > Thanks,
> > >
> > >
> > > Steve.
>
> Steve.
>
> ----------------------------------------------------------------------------
> Before you criticize someone, walk a mile in his shoes. That way, if he gets
> angry, he'll be a mile away - and barefoot.


Regards

--
Julian Anastasov <ja@ssi.bg>