Re: [atomic-devel] We have a bugzilla requesting that we change the default CMD to systemd for base images in RHEL

[Daniel J Walsh <dwalsh redhat com>]

On 10/25/2016 01:43 PM, Josh Berkus wrote:
> On 10/21/2016 01:17 PM, Daniel J Walsh wrote:
>>
>> On 10/21/2016 01:14 PM, Matthew Miller wrote:
>>> On Fri, Oct 21, 2016 at 01:03:58PM -0400, Joe Brockmeier wrote:
>>>> I like Dan's proposal of rhel7-init (or fedora-init, centos-init).
>>> For whatever it's worth, I don't. It makes sense if you're steeped in
>>> the distro world where init systems have been a hot topic for the last
>>> few years, but without that context it sounds like it's something about
>>> inititalizing RHEL/Fedora/CentOS, not that there's a process manager
>>> running. Or even an initial attempt at making a rhel7 container. 
>>>
>> Do you prefer
>> rhel7-systemd, fedora-systemd, centos-systemd
>> or
>> rhel7-system, fedora-system, centos-system
>>
>> Or don't like the idea at all?
> Given that we already get flak ... which leads to reduced adoption ...
> of our base images due to their large size, this seems like the wrong
> direction to move into.
>
> Systemd and its dependencies are quite large, sometimes larger than
> everything else in the container combined, both in storage space and in
> memory footprint.  If we want to push the idea of having systemd inside
> containers, then we need a new tiny version of systemd designed for
> containers.  And by "tiny" I mean "less than 10MB, with few or no
> dependancies which are liable to create extra update churn".
>
> A tiny systemd would be a great selling point.  We'd have integrated
> journaling, more sophisticated PID1 scripts, zombie harvesting, etc.
> Those things are benefits to the developer, and we could promote them.
> But nobody's going to buy those at the cost of 100MB+ of bloat.
>
Well splitting it into two container images rhel7 and rhel7-systemd,
would allow you to
get closer to your deal.  We attempted to do fakesytemd and
systemd-container, but both
ended causing more trouble then they were worth.  We currently ship real
systemd inside
of the RHEL7/Fedora/Centos container images, I  believe it has been
shrunk as far as its dependencies
but removing it would be better, although every daemon package that you
install will pull it
in, since they all currently require systemctl. 

Colin's work on this should improve the situation, and I think we have
shrunk the size of Fedora
images with some of the newer versions of rpm/dnf.