Getting the serial terminal to work over IPMI on a Dell R410

As avid readers of the blog know, we use Hadoop a lot and talk about it quite a bit. We are in the process of expanding our Hadoop cluster and decided to go with the new Dell R410 1U machines.  From talks with other Hadoop users the sweet-spot is one spindle (drive) for every 2 cores on a machine and this machine is the first 1U server from Dell that has this spindle/core ratio.

The one problem we encountered when I received the first test machine was getting the Serial Console to work though the machine’s IPMI interface.  Rapleaf has some other Dell servers and never had any problems, but this machine is new and shiny and just didn’t work with our default configuration.

The first change we needed to make was change the way the BIOS redirects the serial console.  To enter the BIOS press “F2″ after the machine has finished checking its memory.  Once the computer gets to the BIOS go down to “Serial Communication,” you should be seeing the following screen.

The options should be as follows:

• Serial Communication ………. On with Console Redirection via COM2
• Serial Port Address …………… Serial Device1=COM1,Serial Device2=COM2
• External Serial Connector ….. Serial Device2
• Failsafe Baud Rate …………… 115200
• Remote Terminal Type ………. VT100/VT220
• Redirection After Boot ……….. Enabled

When this is done, exit the BIOS and enable IPMI on the machine by pressing CTRL-E when the prompt to modify the IPMI configuration appears and give it an IP address either static or DHCP.

Now there’s a couple of modifications that need to be done to Linux for this to work.

1) The first is modify your /boot/grub/grub.conf file and add “console=ttyS1,115200″ at the end of your kernel parameters.  Ours looks like this:

title Rapleaf Linux (2.6.22)
root (hd0,0)
kernel /vmlinuz-2.6.22 ro root=LABEL=/ console=ttyS1,115200
initrd /initrd-2.6.22.img

2) The last two lines in /etc/inittab should be:

# Run agetty COM2/ttyS1
s1:2345:respawn:/sbin/agetty -L -f /etc/issueserial ttyS1 115200 vt100-nav

3) The last line of /etc/securetty should be

ttyS1

Once all this is done the machine can be rebooted and you should be able to interact with the boot process through IPMI.  Good luck!