Problem Serial console with Redhat Enterprise Version 3.

Philip J. Hollenback phil at telemetry-investments.com
Fri Mar 11 10:10:37 CST 2005


Hi Daniel,

It sounds like the problem is your boot configuration.  What does your
grub.conf look like (assuming you are using grub)?  First, you need to
have the following entries at the top of grub.conf:

serial --unit=0 --speed=9600
terminal --timeout=10 serial console

which makes grub itself use the serial console.  Then, your 'kernel' line
should look something like this:

kernel /vmlinuz-2.6.10 ro root=LABEL=/ acpi=on console=tty0 console=ttyS0,9600

i.e. the last 'console' entry should point to your serial console.
This will make the kernel send messages to the serial console as
well.  It sounds from your description that this is what you are
missing.

The fact that you do get a login prompt on the serial console means
that /etc/inittab is correctly configured to spawn a getty on that
port.

So in summary, these three things have to be configured to make serial
consoles work:

1. grub itself, via serial and terminal entries in grub.conf
2. The kernel, via the kernel entry in grub.conf
3. Login prompts, via /etc/inittab

Hope that helps.  If you use a different boot loader (like lilo
maybe), the same basic principles apply although the configuration
syntax will of course be different.

P.

On 03/11/05, Daniel Schrock wrote:
> Just so you don't feel abandoned, since no one on the list has responded.
> We have the same issue that you are experiencing on the floowing hardware:
> 3x PE6650
> 2x PE2650
> 4x PE1750
> 
> and last but not least, 1 Optiplex Workstation that i used to test
> various options.
> 
> Kernel messages display just fine, then the display stops after init
> until the login prompt appears.
> no boot messages at all, yet if I use 'service' to stop/start/restart
> while logged into the console, the messages display just fine.
> 
> You are not alone, but no one here seems to have any clue as to what is
> going on.
> I also tried a few RHEL/Dell IRC channels and got a little farther, but
> no solution was ever found.
> 
> If you do figure it out, please pass the information along.
> 
> .daniel.schrock,ccnp
> .senior.system/network.architect
> .infrastructure.manager
> .seko.worldwide.
> .p.630.919.4876
> ==================
> The Seko Infrastructure Team uses and recommends The Firefox Web Browser
> http://www.mozilla.org/products/firefox/
> 
> 
> 
> jskim wrote:
> 
> >I am using PowerEdge 750 with Redhat Linux 3.0 update 3.
> >And I am already setting up console login from serial. 
> ># grub.conf generated by anaconda
> >#
> ># Note that you do not have to rerun grub after making changes to this file
> ># NOTICE:  You have a /boot partition.  This means that
> >#          all kernel and initrd paths are relative to /boot/, eg.
> >#          root (hd0,1)
> >#          kernel /vmlinuz-version ro root=/dev/sda8
> >#          initrd /initrd-version.img
> >#boot=/dev/sda
> >default=0
> >fallback=1
> >timeout=10
> >serial --unit=0 --speed=19200 -word=8 --parity=no --stop=1
> >terminal --timeout=10 serial console
> >splashimage=(hd0,1)/grub/splash.xpm.gz
> >title Red Hat Enterprise Linux ES (2.4.21-20.0.1.ELsmp)
> >        root (hd0,1)
> >        kernel /vmlinuz-2.4.21-20.0.1.ELsmp ro root=LABEL=/
> >        console=tty0 console=ttyS0,19200n8r
> >        initrd /initrd-2.4.21-20.0.1.ELsmp.img
> >
> ># /etc/inittab
> >:
> >:
> >c0:12345:respawn:/sbin/agetty 19200 ttyS0 vt100
> >
> ># /etc/securetty
> >:
> >ttyS0
> >
> >
> >But I can not see any boot log during booting and can not use keyboard until
> >Red Hat Linux completely booted from console.
> >
> >How Can I will be able to see boot log during the booting and using keyboard to choose which kernel to boot ?
> >
> >Thanks
> >
> >
> >
> >==================================
> >CISCOPR Copr.
> >Name	: JeongSoo, Kim
> >C/P	: 011-759-6408
> >TEL	: 82-2-2168-8600 ext. 570
> >Mail	: jskim at ciscorp.co.kr
> >=============================
> >
> >_______________________________________________
> >Linux-PowerEdge mailing list
> >Linux-PowerEdge at dell.com
> >http://lists.us.dell.com/mailman/listinfo/linux-poweredge
> >Please read the FAQ at http://lists.us.dell.com/faq
> >  
> >
> 
> _______________________________________________
> Linux-PowerEdge mailing list
> Linux-PowerEdge at dell.com
> http://lists.us.dell.com/mailman/listinfo/linux-poweredge
> Please read the FAQ at http://lists.us.dell.com/faq

-- 
Philip J. Hollenback
Telemetry Investments
phollenback at telemetry-investments.com




More information about the Linux-PowerEdge mailing list