We have four x86-platform “server” appliances left over from an abandoned VoIP project by a consulting company that is now no longer in business. What to do with them? Install Linux, of course, and deploy them as remote network probes for a Smokeping network.
Problem: no console (headless), no peripherals, and it will only boot from the hard disk. It has four serial ports available and network connectivity.
Solution: load a modified Linux installer onto the hard disk. It must redirect the console to a serial port and be able to do a network install of the Linux distribution.
Here’s a summary of the steps I took to install CentOS on the appliances. If you’re interested in details, drop me a line.
- Download diskboot.img from the CentOS 5 distribution. This is a boot image most often used to boot from a USB key. We’re going to write it to the hard disk instead.
- Mount the diskboot.img file on a Linux system and edit the syslinux.cfg file. At the top, add:
serial 0 9600
which tells the installer we’re using serial port 0 (COM1) at 9600 baud. Change the “default” line to:
because the terminal is initially screwed up so we won’t be able to make a choice; we’ll have to let it default to the right one.
Now on “label text” add the following to the end of the “append” line:
which will tell it to boot the kernel and use serial 0 at 9600 baud for the console.
- Save the file and unmount the image.
- Connect the hard drive from the appliance to the Linux machine, and determine its device name. I’ll call it “appliancedisk”.
dd if=diskboot.img of=/dev/appliancedisk
- Now put the appliance’s disk back in place. Connect a terminal to serial line 0 (COM1) and connect the appliance to the network. Boot up and you can control the install process through the terminal, specifying a network location for the install media. Remember to keep the console=ttyS0,9600 line as a boot option so that the serial console continues to work after installation.