Re: [PATCH RFC 0/3] gitlab: build containers to use in build jobs

[Daniel P . Berrangé]

On Thu, Jun 25, 2020 at 01:15:52PM +0200, Thomas Huth wrote:
> On 22/06/2020 17.33, Daniel P. Berrangé wrote:
> > The current gitlab CI jobs are quite inefficient because they
> > use the generic distro images and then apt-get/dnf install
> > extra packages every time.
> > 
> > The other downside is that the container environment used is
> > only defined in thte .gitlab-ci.yml file, so it tedious to
> > reproduce locally.
> > 
> > We already have containers defined in tests/docker for use by
> > developers building locally. We can use these for CI systems
> > too if we just had a way to build them....
> > 
> > ...GitLab CI offers such a way. We can use docker-in-docker
> > to build the images at the start of the CI cycle, and use
> > the built images in later jobs.
> > 
> > These later jobs are now faster because they're not having
> > to install any software.
> 
> Did you see any speed-up? I had a look at some pipelines, and it seems to me
> that they rather got slower now? For example, this is the system1 pipeline
> before your change:
> 
>  https://gitlab.com/huth/qemu/-/jobs/610924897
> 
> and after your change:
> 
>  https://gitlab.com/huth/qemu/-/jobs/611069374
> 
> Duration went up from 35 minutes to 42 minutes.
> 
> Seems also to happen in your builds, before the change:
> 
>  https://gitlab.com/berrange/qemu/-/jobs/582995084
> 
> and after the change:
> 
>  https://gitlab.com/berrange/qemu/-/jobs/606175927
> 
> ... went from 36 minutes up to 42 minutes.
> 
> Could be a coincidence due to the load on the shared runners, but it looks
> at least a little bit suspicious...

I think the difference is because we're building more features now. The
dockerfiles have provided more build pre-requisites that the old gitlab
recipe did.

If you compare the configure summary, I see the new build now covers
SDL, curses, curl, pulseaudio, virtiofs, SASL, libjpeg, xen, docs
and a few more.  So we've saved time by not intsallling many packages
each time, but consumed a greater amount of time by compiling more
features.

Regards,
Daniel
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