Bruce, Ranga, Shogun - Thanks for all of the input - A little clarification I
think might help on what we're trying to do over here...
We have a very simple script that we option to run at z/VM IPL time. IT
autologs 6 Linux guests, 5 of which are WebSphere guests. I consider those 6
the 'production' core even though 3 of them are used for development or QA work
- in any case, what I am looking to do is pass a parameter to that
script ala 'ipllinux nowebsphere' and have that value control what gets passed
to the guest being IPL'ed.
I have looked at the the ability to pass console input data via the xautolog
command but I am cautious there because I don't want to have the guest
read console input data and have it not be there, and get stuck in a read
state. Our VM persons don't like the 'play virtual device games' idea, so
that's out.
What I am thinking is this: Have the IPL script link our LNXADMIN 191 disk and
have it update a file, setting parameters according to what got passed
to the script. That being nowebsphere to start (this could expand in the
future) then since all of the Linux guests profile execs link LNXADMIN 191 as
291 and access it as the 'M' disk, read that file, pull a parm for the
particular guest and pass it on the LOADP parm of the IPL command. What I'm not
sure about is how to have Linux go GET this information and allow me to set an
environment variable that lets the WebSphere startup script in init.d
decide what to do.
I'm not even sure if this full chain of theoretical events is possible, but the
documentation certainly seems to indicate it is possible.
-J
Bruce Hayden <[EMAIL PROTECTED]>
Sent by: Linux on 390 Port
<[email protected]>
To
[email protected]
cc
03/02/2006 08:57 PM
Subject
Re:
Passing a parameter to a linux guest at IPL time
Please respond to
Linux on 390 Port <[email protected]>
Since you're running under VM, you could read a file from a CMS
minidisk using the cmsfs program, or play some tricks using virtual
devices. For instance, your boot process could check to see if a
device exists at a certain virtual address, and if so, don't start
WebSphere. An easy device to create is a virtual printer, as in CP
DEF PRT AS 9999. Then, see if it exists using hcp q v 9999 (or the
vmcp command). If you don't want to depend on the hcp command, define
a 1 cyl tdisk and check to see if it appears in /proc/dasd/devices or
in the output of the lsdasd command (assuming it is a dasd address
defined to the kernel.) If you want to pass a string using a device,
define a printer and put some data in the tag area (up to 136
characters) for the device. You'd have to read that data using the
hcp command.
And then there is the already mentioned method for passing kernel
parameters, as long as you're on SLES 9 or equivalent.
On 3/2/06, James Melin <[EMAIL PROTECTED]> wrote:
> Hi. We'd like to be able to IPL our linux guests at system maintenance time
> but tell them to not start WebSphere until we tell them to. What is the
> best way to pass a parameter to the guest, read the parameter from within the
> guest and then act on it?
>
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--
Bruce Hayden
IBM Global Services System z Linux
Endicott, NY
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