[CI] nested virtualization support in OpenStack CI

Guo, Ruijing ruijing.guo at intel.com
Mon Apr 8 22:54:33 UTC 2019

Hi, Clark

I am trying to add ovsdpdk ci job in neutron. Ovsdpdk need nested virtualization.


-----Original Message-----
From: Clark Boylan [mailto:cboylan at sapwetik.org] 
Sent: Tuesday, April 9, 2019 12:04 AM
To: openstack-discuss at lists.openstack.org
Subject: Re: [CI] nested virtualization support in OpenStack CI

On Mon, Apr 8, 2019, at 5:21 AM, Jeremy Stanley wrote:
> On 2019-04-08 00:42:46 +0000 (+0000), Guo, Ruijing wrote:
> > I like Sean's idea. Can we create jobs based on nested KVM & 
> > customized OS? If CI is stable enough, we can move non-voting to 
> > voting.
> [...]
> There's nothing stopping you (or anyone) from creating such a CI 
> system to augment reporting on how specific workloads fair with 
> certain nested virt implementations.
> The OpenDev CI system on the other hand is made of a heterogenous mix 
> of donations from a variety of service providers with various 
> configurations, and even some of those which advertise via CPU flags 
> that they offer nested virt acceleration don't provide a stable 
> implementation of it. There are already projects opportunistically 
> testing with nested virtualization support turned on in their jobs to 
> varying degrees of success, so it would be good to find out what 
> problems their recent experiences reveal. It's also very much the case 
> that even if it's working for a job today, it can start crashing jobs 
> randomly tomorrow when a kernel version changes on guests or on hosts 
> or we add another service provider into the mix.

Right one of the biggest concerns we have is the lack of observed stability with nested virt. This isn't a theoretical concern. In the not too distant past Tripleo jobs running on CentOS were crashing the "middle" VM and no one noticed until I started looking into job failures. The fix for that required a base hypervisor kernel update which is not something we control.

That said understanding requirements here (which was asked for earlier in the thread, but I don't see a response) is useful when trying to figure out the best way to approach these situations. It is possible there are other reasonable avenues that could be taken.


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