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

[Thomas Huth <thuth@redhat.com>]

On 25/06/2020 13.29, Daniel P. Berrangé wrote:
> On Thu, Jun 25, 2020 at 12:26:53PM +0100, Daniel P. Berrangé wrote:
>> 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.
> 
> Oh a missed a lot more actually - there's also spice, opengl, libiscsi,
> libnfs, libusb, seccomp, libssh, lzo, snappy, bzip, zstd, numa and udev
> too.

Ok, that's fair, I think it's ok to spend some additional minutes for 
the extended test coverage here.

  Thomas