The answer is *High Availability* 2018-06-28 17:40 GMT+02:00 Darac Marjal <[email protected]>:
> On Thu, Jun 28, 2018 at 10:53:58AM -0400, Gene Heskett wrote: > >> On Thursday 28 June 2018 09:23:43 Aleksey Kravchenko wrote: >> >> Hi. >>> Is there a free alternative to ksplce / livepatch / kernelcare for >>> debian systems? We're interested in the complete solution when we >>> install the agent on the server and the agent upgrades the system by >>> itself. Thank you. >>> >> >> Given the history of ksplice, and my innate paranoia, I don't have a pole >> long enough to reach it. You shouldn't either. I have a mental picture >> of the keys to whatever merchandising operation you may be involved in, >> hanging on a nail beside the front door. >> >> If something is patched and a reboot is needed to make it 100% >> functional, and you can't stand the thought of 2 minutes downtime while >> its rebooting, its time to mirror your app to a second machine and >> configure an automatic failover. There are some OS's that can do that, >> QNX comes to mind, but they aren't free. Even the QNX microkernel has a >> dead time of 15 or 20 seconds for a full reload of everything else. >> > > 2 minutes? I presume you've not interacted much with modern servers? HPe > ProLiant servers, for example, take several minutes to reboot (a couple of > minutes initialsing the processor/BMC, then they switch to graphical mode > and initialise RAM, sensors, devices etc, then they begin to boot. And then > you've got whatever time is needed to get, say, your storage in order...) > > I think that the closest that Debian comes to ksplice is kexec. kexec is > the kernel equivalent of the shell's exec function; that is, "execute that > process in place of this one". To use kexec, you still need to run through > your init scripts to shutdown the system and restart it but, instead of > asking the system firmware to reboot the system, the kernel calls the kexec > function and executes the new kernel in place. All your RAM stays "hot", > all your devices remain initialised etc, but you do need to restart the OS. > So it's a compromise. > > > >> I think the applicable keyword here is TANSTAAFL. Its a universal law, >> and there are no shortcuts around it. IOW, if you think the lunch is >> free, check the price of the beer. >> >> -- >> Cheers, Gene Heskett >> -- >> "There are four boxes to be used in defense of liberty: >> soap, ballot, jury, and ammo. Please use in that order." >> -Ed Howdershelt (Author) >> Genes Web page <http://geneslinuxbox.net:6309/gene> >> >> > -- > For more information, please reread. > -- .~. /V\ // \\ /( )\ ^`~'^
