[gridengine users] How to export an X11 back to the client?

Mun Johl Mun.Johl at wdc.com
Thu May 7 18:29:05 UTC 2020


Hi William, et al.,

Thank you kindly for your response and insight.
Please see my comments below.

> On Wed, May 06, 2020 at 11:10:40PM +0000, Mun Johl wrote:
> > [Mun] In order to use ssh -X for our jobs that require an X11 window to be pushed to a user's VNC display, I am planning on the
> following changes.  But please let me know if I have missed something (or everything).
> >
> > 1. Update the global configuration with the following parameters:
> >
> >      rsh_command         /usr/bin/ssh -X
> >      rsh_daemon          /usr/sbin/sshd -i
> 
> As you are using the pam_sge-qrsh-setup.so you will need to set
> rsh_daemon to point to a rshd-wrapper which you should find in
> $SGE_ROOT/util/resources/wrappers eg if $SGE_ROOT is /opt/sge
> 
> rsh_command /usr/bin/ssh -X
> rsh_daemon /opt/sge/util/resources/wrappers/rshd-wrapper

[Mun] Thanks for pointing out my mistake!

> > 2. Use a PAM module to attach an additional group ID to sshd.  The following line will be added to /etc/pam.d/sshd on all SGE
> hosts:
> >
> >       auth required /opt/sge/lib/lx-amd64/pam_sge-qrsh-setup.so
> >
> > 3. Do I need to restart all of the SGE daemons at this point?
> 
> No it should be fine without a restart
> 
> >
> > 4. In order to run our GUI app, launch it thusly:
> >
> >       $ qrsh -now no wrapper.tcl
> 
> That looks fine, assuming sensible default resource requests, although
> obviously I don't know the details of the wrapper or application.

[Mun] After making the above changes, I'm still experiencing problems.  First, let me point out that I should have more accurately represented how qrsh will be used:

$ qrsh -now no <other qrsh options> tclsh wrapper.tcl <options for wrapper script>

Now for the issues:

I first added the pam_sge-qrsh-setup.so at the top of the /etc/pam.d/sshd file.  When I did that the qrsh job was launched but quickly terminated with the following error from the tool I was attempting to launch:

ncsim/STRPIN =
	The connection to SimVision could not be established due to an error
	in SimVision. Check your DISPLAY environment variable,
	which may be one of the reasons for this error.

I am not explicitly setting the DISPLAY--as that is how I normally use 'ssh -X'.  Nor have I done anything to open any additional ports.  Again, since 'ssh -X' is working for us.  As a reminder, there is no way for me to know what to set DISPLAY to even if I wanted to set it.

Now, the /etc/pam.d/sshd update caused an ssh issue: Users could no longer ssh into our servers :(  I didn't realize the order of the lines in the sshd is significant.

Therefore, I moved the pam_sge-qrsh-setup.so entry below the other "auth" lines.  Although, that resulted in the following error when I tried the qrsh command again:

     Your "qrsh" request could not be scheduled, try again later.

One final note is that we have "selinux" enabled on our servers.  I don't know if that makes any difference, but I thought I'd throw it out there.

Feedback would be most welcome.

Best regards,

-- 
Mun





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