More as a reminder to myself for when I need this again, but I’m sure everyone needs this at least once.
Having screwed up my kernel configs for my VirtualBox Gentoo image, I needed a serial console to catch the boot messages scrolling past in order to see if all the required hardware was being loaded by the kernel. I’ve never done this on a physical machine before but I am converted now and will acquire a USB to serial port converter in the near future…
Using this article as a base you need to do the following:
- Enable serial ports for your virtual machine
- Select “Host Pipe”
- Enter /tmp/vboxconsole as the filename
- Use netcat to read the console: nc -U /tmp/vboxconsole
When booting you need to amend your grub boot line to have the following at the end:
console=ttyS0,38400
Making it look something like this:
kernel=/kernel-2.6.30-r6 root=/dev/sda3 console=ttyS0,38400
Proceed to boot and look at netcat to see the entire boot output scroll past without disappearing into thin air when the kernel panics.
Man, I love virtualization. I tested this on Mac OS X 10.5 with VirtualBox 3.0.6, but it should work on any *nix platform. Some more Gentoo serial console madness can be found on the old Gentoo Wiki.
The console parameter is a kernel-standard thing for all distributions that I know, don’t think there are many mainstream ones that disable it. Also, I recommend buying an extra DB9 male-male barrel and a ~1.5m male-female extension in the same go as buying the USB-serial cable, since they’re always good to have around for when you just can’t quite reach that server in the back.