Cloud product kernel requirements

[Haïkel Guémar]

Le 30/10/2013 15:07, Josh Boyer a écrit :
> Hi All,
>
> I realize the WG is just forming up and you have a lot of other items
> to cover for now, but I wanted to get this sent out and have people
> start thinking about it sooner rather than later.
>
> The kernel team has heard in the past that the Cloud group would like
> to see something of a more minimal kernel for usage in cloud images.
> We'd like to hear the requirements for what this smaller image would
> need to cover.
>
> Right now, a default x86_64 kernel package on f20 is ~134MB installed.
>   Most of that is device drivers installed in /lib/modules/`uname -r`/.
>   The vmlinux binary is about 5MB and the initramfs (which is created
> at install time and can actually vary quite widely depending on
> various things) is about 11MB.  Drivers can be trimmed to a degree,
> but please keep in mind that the kernel is already relatively small
> for the functionality it provides.  For example, it is not much bigger
> than glibc-common (119MB).
>
> So, some caveats to keep in mind while you're thinking about this:
>
> 1) We're mostly talking about packaging here, not building a separate
> cloud kernel package or vmlinux.  The kernel team really wants to have
> a single vmlinux across the 3 products if at all possible.  We can't
> scale to much else.
Seems reasonsable.
> 2) What usecases is the cloud image going to cover?  E.g. is it just
> virtio stuff, or will it also fit PCI passthru (which then requires
> drivers for those PCI devices)?

We're still discussing our targeted platforms.
As for PCI pass-through, if we target hypervisors (KVM, Xen) or 
virtualization platforms (oVirt, vSphere), it will be a requirement, if 
we target {I,P}aaS platforms, not so much.


> 3) What are the common provisioning requirements that are driving the
> size reduction?  (See comment about glibc-common.  I would think
> change is needed in multiple packages, not just the kernel.)

As you pay for storage, the more trimmed down image we can bring, the 
better.
For instance, Ubuntu AWS image is about 228MB compressed and they do 
pretty well on that matter
Uncompressed the raw disk image is 1.5 GB, and the vmlinux 5 MB

4) Other "cloudy" stuff that I'm entirely unaware of that might be
relevant.  Explain it to me like I'm a child.

Thanks!

josh


Thank you for sharing your concerns with us.

Best regards,
H.