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Linux can be upgraded without a full reboot using the now-somewhat-ancient two-kernel-monte, or kexec? Plan 9 had been able to load new kernels and such withou

Linux can be upgraded without a full reboot using the now-somewhat-ancient two-kernel-monte, or kexec? Plan 9 had been able to load new kernels and such without rebooting the machine fully as well. I love when people make crazy claims like "NO ONE ELSE CAN DO THIS... I MEAN WE NEVER ACTUALLY VERIFIED THIS OR LOOKED BUT WE'RE PRETTY SURE NO ONE ELSE CAN DO THIS!" Should go into marketing where that crap is allowed.

butterisgood 9y ago
Or at least explain how it's different from the existing things that work pretty well.
john75 9y ago
i have to admin that im not totally familiar with the internal works of kexec, but at least from my knowledge a full service restart is required[0]. The Minix team claims the upgrade happens "without running processes even noticing", that sounds better than restarting all the services. [0] https://ma.ttias.be/kernel-patching-kexec-updating-centos-7-kernel-without-full-reboot/ https://ma.ttias.be/kernel-patching-kexec-updating-centos-7-...
snvzz 9y ago
>Linux can be upgraded without a full reboot using the now-somewhat-ancient two-kernel-monte, or kexec? Sure, and some time is saved, as the firmware/bootloader doesn't need to run. But otherwise, like with a reboot, everything is shut down and restarted. Minix3 can update system servers and drivers in place, without rebooting and without user processes even feeling a hiccup. It can even go back to the older, working version if there's any issue with the new one. >I love when people make crazy claims like "NO ONE ELSE CAN DO THIS... I MEAN WE NEVER ACTUALLY VERIFIED THIS OR LOOKED BUT WE'RE PRETTY SURE NO ONE ELSE CAN DO THIS!" And I'm still waiting to see such an example. Linux's kexec is not.
zlynx 9y ago
Linux can use kpatch to upgrade the kernel while it is running. The difficult part is writing and validating the actual patch. I recall that the only people writing kpatches charge a lot of money for them and only provide them to their paying support customers. Then all of the free software people complain loudly. Yet, you don't see THEM writing (and TESTING) these functions to update in-kernel data structures in place.

butterisgood 9y ago

Or at least explain how it's different from the existing things that work pretty well.

john75 9y ago

i have to admin that im not totally familiar with the internal works of kexec, but at least from my knowledge a full service restart is required[0]. The Minix team claims the upgrade happens "without running processes even noticing", that sounds better than restarting all the services. [0] https://ma.ttias.be/kernel-patching-kexec-updating-centos-7-kernel-without-full-reboot/ https://ma.ttias.be/kernel-patching-kexec-updating-centos-7-...

snvzz 9y ago

>Linux can be upgraded without a full reboot using the now-somewhat-ancient two-kernel-monte, or kexec? Sure, and some time is saved, as the firmware/bootloader doesn't need to run. But otherwise, like with a reboot, everything is shut down and restarted. Minix3 can update system servers and drivers in place, without rebooting and without user processes even feeling a hiccup. It can even go back to the older, working version if there's any issue with the new one. >I love when people make crazy claims like "NO ONE ELSE CAN DO THIS... I MEAN WE NEVER ACTUALLY VERIFIED THIS OR LOOKED BUT WE'RE PRETTY SURE NO ONE ELSE CAN DO THIS!" And I'm still waiting to see such an example. Linux's kexec is not.

zlynx 9y ago

Linux can use kpatch to upgrade the kernel while it is running. The difficult part is writing and validating the actual patch. I recall that the only people writing kpatches charge a lot of money for them and only provide them to their paying support customers. Then all of the free software people complain loudly. Yet, you don't see THEM writing (and TESTING) these functions to update in-kernel data structures in place.