[daip] Fwd: Remote use of AIPS

[Patrick P Murphy]

On Tue, 26 Sep 2006 10:59:20 -0600, Jared Crossley <jcrossle at nrao.edu> said:

> I sent the following AIPS question to Eric Greisen, but Lorant 
> suggested I send it to daip instead.

> My latest attempt, as suggested by Lorant, is described at the bottom.

What Amy and Wes said are correct.  However, here's what went wrong with
your earlier attempt:

>> I'm trying to run AIPS remotely on imager-b.aoc.nrao.edu with a local
>> TV on my Mac laptop, named jhc.

>> I can start an AIPS session just fine on jhc; the TV opens and 
>> everything.

>> Then I ssh to imager-b.  I can open X-Windows apps on imager-b and 
>> display them on jhc.

Presumably the DISPLAY is set to something like localhost:10 and ssh
tunneling is being used.

>> However, when I start AIPS on imager-b, I get the following messages:
>> ----
>> START_AIPS: I am GUESSING you are at a workstation called jhc

So far so good.  It knows where you are.

>> TVDEVS.SH: Remote TV assigned for TVHOST jhc  ***
>> START_AIPS: Checking if jhc is reachable via ssh...

It is doing (from imager-b) a ssh command to jhc.  Do you have a ssh
server running on your Mac?  In other words, can you do this:

   imager-b$ ssh jhc pwd

and get it to show your home directory on jhc?  If not, then the attempt
by the AIPS startup on imager-b to fire up the XAS, Message and Tek
servers can't possibly work.

>> START_AIPS: Cannot start remote TV servers on jhc, sorry!
>> START_AIPS: remote command gave this error:
>> ssh: jhc: Name or service not known

This suggests that imager-b can't ssh to (or ping) jhc.

>> When I run 'ssh -v jhc pwd' from imager-b, I get:
>> ----
>> imager-b<2>% ssh -v jhc pwd
>> OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003
>> debug1: Reading configuration data /etc/ssh/ssh_config
>> debug1: Applying options for *
>> ssh: jhc: Name or service not known
>> ----

Weird.  

>> Some issues that may be relevant:
>> 1) jhc is my laptop, and is assigned an IP address by DHCP.

>> 2) To ssh from imager-b to my laptop I use the following command, 'ssh 
>> jared at jhc.aoc-vis.nrao.edu'

The DNS search path on imager-b (in /etc/resolv.conf) probably doesn't
have aoc-vis.nrao.edu in it.  So short names like "jhc" don't get a
domain tacked on to them when name lookup via DNS is done.  On imager-b
if you type "host jhc" it probably won't work.

>> 3) My user name on my laptop is Not the same as my user name on the 
>> AOC network: "jared" on laptop; "jcrossle" on AOC computers.

Easy to cure in /users/jcrossle/.ssh/config on an AOC computer:

Host jhc.aoc-vis.nrao.edu
     User jared

This will make sure the "jared" account is used when you ssh from your
jcrossle account on any AOC Unix computer, to your Mac.

However, that won't solve the resolv.conf issue.  The helpdesk can
probably help there.

The pragmatic thing to do is start the TV on jhc, then log into imager-b
and start AIPS with "aips tv=jhc.aoc-vis.nrao.edu tvok".  I think
that'll work.

>> Regarding the instructions in the AIPS cookbook, p.12-14, jhc and 
>> imager-b have different byte orders.  I have set environment variable 
>> DISPLAY on imager-b to jhc.aoc-vis.nrao.edu:0 .  I have created file 
>> jhc:~jared/.rhosts with one line, 'imager-b.aoc.nrao.edu jcrossle'.  

I'd nuke the .rhosts file; it's not only not useful, but a security
liability.

 - Pat (still lurking on the daip list)

-- 
 Patrick P. Murphy, Ph.D.   Senior Software Engineer, ALMA Computing IPT
 NRAO Computing Security Manager       Head, NRAO WebAdmin Working Group
 Home: http://goof.com/~pmurphy/     Work: http://www.nrao.edu/~pmurphy/
 "Inventions then cannot, in nature, be a subject of property."
                                    -- Thomas Jefferson, August 13, 1813