Virtualizing the locomotive [LWN.net]

Virtualizing the locomotive

Posted Sep 17, 2015 14:57 UTC (Thu) by pj (subscriber, #4506)
Parent article: Virtualizing the locomotive

Has anyone built some kind of 'virtualization concurrence' layer? The idea would be to present the same VM to two sets of software, one live and one that's supposed to 'concur' (ie. produce the same (or better?) outputs to some VM facility). This way you run production software as 'live' and your new version as 'supposed to concur' and can see when/if it doesn't. A slight modification might allow the 'multiple masters must concur before action is take' kind of redundancy that things like space vehicles used to implment.

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Virtualizing the locomotive

Posted Sep 18, 2015 17:38 UTC (Fri) by jki (subscriber, #68176) [Link]

COLO (course-grained lock-step for KVM) is aiming at a different use case (hot-standby) but basically comes with the host-side piecees to enable this.

But this alone may not help to improve the overall confidence in the produced results. Depending on the target application, regulatory requirements etc., you may also need diversity in the infrastructure, i.e. the virtualization platform AND the hardware. Or you need to verify that both behave correctly in absence of hardware errors and that they detect all errors reliably enough. That will be tough to achieve with a normal virtualization stacks, and that's why we started the Jailhouse hypervisor project.