On Fri, Jan 30, 2009, Paul Jakma wrote: > What would be the best way to have some kind of support for retaining > old kernel/initrds and booting those? (And is anyone working on this?)
We were looking into this in Ubuntu; actually the general problem was recovering from a breakage after a kernel/initrd upgrade, and allowing to boot older kernel/initrds. There are many solutions to the first part, perhaps our preferred is when the bootloader is clever enough to e.g. boot from USB or SD card first, or even clever enough to offer you a list of kernels from a partition on your SATA disk! Unfortunately RedBoot isn't really good at FS and USB or SATA would require new support in RedBoot. Michael Casadevall explored this option: > - A small, static Linux env in flash to act as bootloader via kexec ? ...and ran into problems with kexec on a target board we're using. He explored building an env from kboot and petitboot. Oliver Grawert explored adding an initramfs-tools boot script to present a menu, all in shell. These solutions were quite promising, but required some hacks. With kboot/petitboot, you're bloating the initramfs size, probably would still fit in the case of the Thecus N2100 though (in our case, even a standard initramfs wouldn't fit). Also, this is no silver bullet: you still want to be able to recover from breakage in the flash's kernel/initramfs, or upgrade them (even if less regularly), and it will require starting two kernels, hence making boot times longer. You also face a prompting problem on the Thecus N2100 which doesn't have a display/console by default (you can of course solder it in, but that's less user friendly ;-) and going the telnet/ssh route might make it a) insecure b) slower to boot c) tricky to actually log in during the open window. https://lists.ubuntu.com/archives/ubuntu-devel/2009-January/027229.html https://wiki.ubuntu.com/Specs/ARMSoftbootLoader I'll forward your comments to Michael and Oliver; we are and remain very interested in your ideas and input! Right now we're likely to go with the bootloader route as it supports SD boot, but a more generic solution would probably involve a Linux kernel and an initramfs if we want drivers to access hardware, filesystems, and perhaps things like LVM/crypto devices and offer some logic to select the image. Bye -- Loïc Minier -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
