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Re: [Freeipmi-users] Serial Console hang during reboot


From: Phil Pokorny
Subject: Re: [Freeipmi-users] Serial Console hang during reboot
Date: Sat, 27 Aug 2011 12:55:33 -0700

I wonder if the BMC internal Linux kernel is generating a HUP on
carrier detect changing during the reboot and killing the SOL process
inside the BMC.

The plan was to use a console monitoring/aggregation tool like Conman
or Conserver so we'll look into implementing serial keepalive there.

Is there a non-data packet you could send (like telnet are-you-there)
or a duplicate tcp ack that you could send instead of nul bytes that
make their way into the input stream?

Thanks,
Phil P.

-- 
Philip Pokorny, RHCE
Chief Hardware Architect
PENGUIN COMPUTING, Inc
www.penguincomputing.com

On Aug 27, 2011, at 9:29 AM, Al Chu <address@hidden> wrote:

> Hi Phil,
>
> I haven't personally witnessed this, but I have heard of this
> happening
> before.
>
> There is no direct workaround, since the problem is on the
> motherboard.
> My assumption is that internally the BMC-UART connection on the
> motherboard is reset in some way during a reboot.  From the client
> perspective, the IPMI connection is fine and dandy.
>
> Although not available w/ the ipmiconsole tool itself, there is an
> indirect workaround in the libipmiconsole library called
> SERIAL_KEEPALIVE.  As the name suggests, it implements keepalive
> messages via serial data instead of IPMI data (internally, it sends
> NUL
> chars once in awhile).  That way, tools like Conman or Conserver can
> detect the lost connection quickly and restart it.
>
> If you're interested, I can add the workaround as an option to
> ipmiconsole too.  I only left it in libipmiconsole b/c I considered
> this
> a problem for Conman/Conserver, not for a user using ipmiconsole on
> the
> command line.
>
> Al
>
> On Fri, 2011-08-26 at 20:27 -0700, Phil Pokorny wrote:
>> Has anyone else had problems with the BMC and ipmiconsole app
>> loosing "sync"
>> during a reboot?
>>
>> The serial console redirect is working fine, then we reboot the
>> server and
>> after the reset, there is no more serial console data.
>> Disconnecting and
>> reconnecting to the BMC restores the flow of serial console data.
>>
>> Is there a work-around switch in FreeIPMI to deal with this
>> behavior? Is
>> there a "hangup" signal coming from the host that's being ignored by
>> ipmiconsole?
>>
>> System is a Supermicro motherboard with the Winbond BMC and AMI
>> firmware.
>>
>> Thanks,
>> _______________________________________________
>> Freeipmi-users mailing list
>> address@hidden
>> https://lists.gnu.org/mailman/listinfo/freeipmi-users
> --
> Albert Chu
> address@hidden
> Computer Scientist
> High Performance Systems Division
> Lawrence Livermore National Laboratory
>



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