I have a headless Linux box and every time I reboot it there’s a several minute anxiety where I don’t know if it’s working or not. (I reboot only every year or so, I think fsck’s timer kicks in and it takes awhile.)
I want to see the console while its booting, without a monitor. I don’t want to fuss with serial cables. Netconsole looks like an option; kernel module that sends UDP log messages via a pre-arranged MAC address. Before the TCP/IP stack is initialized. Docs: Ubuntu, Arch, kernel.