Modular Kernel Packaging for Cloud

[Josh Boyer]

On Thu, Mar 6, 2014 at 12:04 PM, Don Zickus <dzickus at redhat.com> wrote:
> On Thu, Mar 06, 2014 at 11:32:55AM -0500, Matthew Miller wrote:
>> On Thu, Mar 06, 2014 at 11:02:47AM -0500, Josh Boyer wrote:
>> > If it's _necessary_, that's one thing.  I've yet to really see any data
>> > backing up necessity on any of this at all though.  Right now it seems
>> > to be sitting in the "nice to have" category.
>>
>> For the record, it is _literally_ sitting in our "nice to have" category.
>> See
>> https://fedoraproject.org/wiki/Cloud_Changelist#Change:_Cloud-Friendly_Kernel_Packaging
>>
>> :)
>>
>>
>> > Perhaps someone from the cloud team could look at existing images from
>> > other distros and figure out kernel sizes there, and how it plays into
>> > usage and cost in those environments?
>>
>> On the ubuntu EC2 image, /lib/modules/$(uname -r) is 24M + 5.2M vmlinuz +
>> 1.1M in /lib/firmware. Total package size is 32M on disk. And 5.9M initrd.
>>
>> CoreOS is bigger, with 33M in /lib/modules and 5.2M in lib/firmware, and a
>> /19M vmlinuz.
>
> Yeah, hard numbers to compete with! :-)

The only way to win is to not play at all? :)

Small note too, just because the vmlinuz are of a certain size does
not mean they contain similar content.  Without really digging into
the config settings it's hard to do a true apples to apples
comparison.  Still, having the overall sizes handy is helpful, thanks.

> I think Josh is mostly there.  He has 58MB + 5M vmlinuz + <similar?>
> firmwre.

Firmware is owned by linux-firmware, not the kernel package.  I didn't
include it in my kernel numbers for that reason.

> He just has to cut 35MB or so from /lib/modules/.  We can probably nickel
> and dime and review a lot of cruft to get there, but what is that 35MB
> really doing to get us anything?  I am sure half of that can be removed by
> re-examining the minimal-list he sent (I can even help there).

Right.  Considering the bloat elsewhere in the distro, I think we can
start with what I have and work from there if needed.

> Maybe impose only xfs as the fs of choice or some other restrictions and
> chop it further, but then we lose flexibility.

Oh dear.  Please not another FS thread.  So many emails from last week...

> Instead of competing with Ubuntu on minimalist can we compete on pretty
> close but a lot more flexible?  Do Ubuntu users have much choice on how
> they configure their environment?  Or is Fedora Cloud providing a generic
> cookie cutter installation?

Right, I kind of like that we'd have a smaller core package that is
still broadly useful.

josh