[CentOS-devel] kpatch process

> -----Original Message-----
> From: centos-devel-bounces at centos.org [mailto:centos-devel-
> bounces at centos.org] On Behalf Of Jim Perrin
> Sent: 21 June 2014 03:08
> To: The CentOS developers mailing list.
> Subject: Re: [CentOS-devel] kpatch process
> 
> 
> 
> On 06/20/2014 06:13 PM, Karanbir Singh wrote:
> > On 06/20/2014 06:30 PM, Jim Perrin wrote:
> >>
> >>
> >> On 06/20/2014 12:15 PM, Karanbir Singh wrote:
> >>> hi
> >>>
> >>> since we now have a GA kernel and a zero day update kernel, does
> >>> someone want to have a go at creating the scripts / automation
> >>> needed to deliver kpatch content ?
> >>>
> >>> - KB
> >>>
> >>
> >> Sat through a basic presentation on this, and on the surface it seems
> >> reasonably easy to implement at the local level. Distro wide, it will
> >> become an exercise in deployment of patches, as not all things can be
> >> patched. There's also a reasonably insignificant (or so I'm told)
> >> performance penalty that will grow as more things are added to the
> >> kpatch list without a reboot.
> >
> > something really cool is that the kpatch process itself works quite
> > nicely with git, we could potentially deliver a tool that allows
> > people to self-implement, rather than needing to ship kpatch payload (
> > otherwise, were potentially looking at a yum plugin of sorts and a rpm
> > based wrapper )
> >
> > does that sound like something we could target ?
> 
> 
> Possibly, however; we haven't seen upstream deliver a kpatch, and I'm not
> convinced they intend to provide anything more than the functionality to make
> one yourself.
> 
> So, we would have to extract and prepare the source of the old kernel, and the
> new. Diff them to generate a patch that could be distributed through git.
> 
> That patch may or may not be able to be applied via kpatch.
> Additionally, how far back would we like to provide diffs? Do we start with the
> release kernel for each minor version and keep a diff? Do we only patch for the
> previous kernel version?
> 
> 
> I can see this feature being incredibly popular with hosters, but it would require
> a fair bit of planning on our part to implement properly.
> 

Kpatch is a really interesting technology for the CERN cloud use cases on the hypervisors which are long running servers.

However, I think we should focus on getting the builds done first so we have something to patch :-) I would favour a centrally provided set of patches in view of the complexity of the process and the benefits of community testing. 

Tim

> --
> Jim Perrin
> The CentOS Project | http://www.centos.org
> twitter: @BitIntegrity | GPG Key: FA09AD77
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