Has anyone gotten Grub2 to load via Linux Kexec? It used to be possible to kexec grub.exe for some reason.
I have been tasked tonight to reboot a very critical production server during a short window. It's long enough, but at the moment our big issue is that the reboot will be somewhere between 3-5 minutes up to 18 minutes (we don't know) because server hardware does a ton of self-check and has RAID, Video, bootrom, etc BIOS crap to go through. Years ago, this came up and Kexec was written. Nobody uses it. We use it for fancy debugging but that's it. So I propose: We must find a method of rebooting into A) a bootloader entry; or B) directly into Grub2 and let it boot the system. (B) would be less fragile, as any incorrectness in (A) will at best make kexec fail during late-stage shutdown and at worst load the kernel with invalid parameters and cause a panic before mounting rootfs (a nightmare without remote console). Loading the bootloader can only fail in general, in which case we can go as far as re-initializing init onto an operating runlevel and come back up without a reboot (white hot reboot). So: - Cold boot (physical power cycle) - Warm boot (ACPI reboot) - Red hot boot (drop back and reload the kernel/bootloader) - White hot boot (shutdown completely, then go back into a live runlevel rather than halt or reboot) We're attempting a red hot boot, and on soft failure coming out via a white hot boot. If Linux can respond to panic() by warm boot, that would be very optimal. (Spoiler: the next logical step would be porting freeze/thaw from Dragonfly so you can reboot into a new kernel without closing your desktop session. Yes, this is totally doable. You would not believe the insanity that is physically possible.) -- Ubuntu-devel-discuss mailing list Ubuntu-devel-discuss@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel-discuss
