kexec on panic

[Clif Houck]

Is it possible to kexec on demand (not panic!) into another kernel with
the idea being to avoid a reboot?

For instance, say you had Linux running in a ramdisk, and all that
ramdisk Linux did was lay down a bootable Linux image onto the main
disk, and then awaited a command to kexec to the Linux image on disk? Is
something like that possible? Would I still need to specially craft the
initrd? If so, is there any literature available on how to do that?

Thanks,
Clif Houck

On 2/10/2017 9:43 AM, Petr Tesarik wrote:
> On Fri, 10 Feb 2017 10:14:02 +0200
> Denys Fedoryshchenko <nuclearcat at nuclearcat.com> wrote:
> 
>> Hello,
>>
>> After years of using kexec and recent unpleasant experience with modern 
>> (supposed to be blazing fast to boot) hardware that need 5-10 minutes 
>> just to pass POST tests,
>> one question came up to me:
>> Is it possible anyhow to execute regular (not special "panic" one to 
>> capture crash data) kexec on panic to reduce reboot time?
> 
> No. But you can load a specially crafted panic initrd which kexec's
> back to the production kernel.
> 
> HTH,
> Petr T
> 
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