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That works for detecting changes in the build system.

It does not solve the issue of how to keep containers atomic on end user systems.

All images in a k8s deployment should be the same image. This is done by specifying the same tag. When a new update is done, the updated deployment should specify a new tag to distinguish it from the old tag so that roll forwards/roll backs work atomically and as designed. Otherwise, roll back can actually break or roll forward wont actually grab newer images.

Thanks,
Kevin

________________________________________
From: Michał Jastrzębski [inc007 at gmail.com]
Sent: Wednesday, April 19, 2017 8:32 AM
To: OpenStack Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] [kolla] Tags, revisions, dockerhub

I think LABEL is great idea for all the "informative" stuff. In fact
if we could somehow abuse LABEL to fill it up after we get packages
installed, we could use it for version manifesto. That will make logic
around "if version changed" much easier since we'll have easy access
to this information on both image and container.

Our autopushing mechanism will work with tags and HEAD of stable
branch in this case.

Kevin, then your use case would be done like that:
1. pull container nova-compute:ocata, tag it locally to
nova-compute:ocata-deployed, deploy it
2. every now and then pull fresh nova-compute:ocata from dockerhub
3. compare versions in LABELs to see whether you want to upgrade or not
4. if you do, retag :ocata-deployed to :ocata-old, :ocata to
:ocata-deployed and run upgrade
5. keep ocata-old, revision it, backup it for as long as you want

I also think that we can ship utils to do this in kolla, so people
won't need to write these themselves.

Does that work?

Cheers,
Michal

On 19 April 2017 at 05:02, Flavio Percoco <flavio at redhat.com> wrote:
> On 19/04/17 11:20 +0100, Paul Bourke wrote:
>>
>> I'm wondering if moving to using docker labels is a better way of solving
>> the various issue being raised here.
>>
>> We can maintain a tag for each of master/ocata/newton/etc, and on each
>> image have a LABEL with info such as 'pbr of service/pbr of kolla/link to CI
>> of build/etc'. I believe this solves all points Kevin mentioned except
>> rollback, which afaik, OpenStack doesn't support anyway. It also solves
>> people's concerns with what is actually in the images, and is a standard
>> Docker mechanism.
>>
>> Also as Michal mentioned, if users are concerned about keeping images,
>> they can tag and stash them away themselves. It is overkill to maintain
>> hundreds of (imo meaningless) tags in a registry, the majority of which
>> people don't care about - they only want the latest of the branch they're
>> deploying.
>>
>> Every detail of a running Kolla system can be easily deduced by scanning
>> across nodes and printing the labels of running containers, functionality
>> which can be shipped by Kolla. There are also methods for fetching labels of
>> remote images[0][1] for users wishing to inspect what they are upgrading to.
>>
>> [0] https://github.com/projectatomic/skopeo
>> [1] https://github.com/docker/distribution/issues/1252
>
>
>
> You beat me to it, Paul.
>
> I think using lables to communicate the version of each openstack software
> installed in the image is the way to go here. We're looking into doing this
> ourselves as part of the RDO pipeline and it'd be awesome to have it being
> part
> of kolla-build itself. Steve Baker, I believe, was working on this.
>
> The more explicit we are about the contents of the image, the better. People
> want to know what's in there, rather than assuming based on the tag.
>
> Flavio
>
>
>> -Paul
>>
>> On 18/04/17 22:10, Michał Jastrzębski wrote:
>>>
>>> On 18 April 2017 at 13:54, Doug Hellmann <doug at doughellmann.com> wrote:
>>>>
>>>> Excerpts from Michał Jastrzębski's message of 2017-04-18 13:37:30 -0700:
>>>>>
>>>>> On 18 April 2017 at 12:41, Doug Hellmann <doug at doughellmann.com> wrote:
>>>>>>
>>>>>> Excerpts from Steve Baker's message of 2017-04-18 10:46:43 +1200:
>>>>>>>
>>>>>>> On Tue, Apr 18, 2017 at 9:57 AM, Doug Hellmann
>>>>>>> <doug at doughellmann.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Excerpts from Michał Jastrzębski's message of 2017-04-12 15:59:34
>>>>>>>> -0700:
>>>>>>>>>
>>>>>>>>> My dear Kollegues,
>>>>>>>>>
>>>>>>>>> Today we had discussion about how to properly name/tag images being
>>>>>>>>> pushed to dockerhub. That moved towards general discussion on
>>>>>>>>> revision
>>>>>>>>> mgmt.
>>>>>>>>>
>>>>>>>>> Problem we're trying to solve is this:
>>>>>>>>> If you build/push images today, your tag is 4.0
>>>>>>>>> if you do it tomorrow, it's still 4.0, and will keep being 4.0
>>>>>>>>> until
>>>>>>>>> we tag new release.
>>>>>>>>>
>>>>>>>>> But image built today is not equal to image built tomorrow, so we
>>>>>>>>> would like something like 4.0.0-1, 4.0.0-2.
>>>>>>>>> While we can reasonably detect history of revisions in dockerhub,
>>>>>>>>> local env will be extremely hard to do.
>>>>>>>>>
>>>>>>>>> I'd like to ask you for opinions on desired behavior and how we
>>>>>>>>> want
>>>>>>>>> to deal with revision management in general.
>>>>>>>>>
>>>>>>>>> Cheers,
>>>>>>>>> Michal
>>>>>>>>>
>>>>>>>>
>>>>>>>> What's in the images, kolla? Other OpenStack components?
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Yes, each image will typically contain all software required for one
>>>>>>> OpenStack service, including dependencies from OpenStack projects or
>>>>>>> the
>>>>>>> base OS. Installed via some combination of git, pip, rpm, deb.
>>>>>>>
>>>>>>>> Where does the
>>>>>>>> 4.0.0 come from?
>>>>>>>>
>>>>>>>>
>>>>>>> Its the python version string from the kolla project itself, so
>>>>>>> ultimately
>>>>>>> I think pbr. I'm suggesting that we switch to using the
>>>>>>> version.release_string[1] which will tag with the longer version we
>>>>>>> use for
>>>>>>> other dev packages.
>>>>>>>
>>>>>>> [1]https://review.openstack.org/#/c/448380/1/kolla/common/config.py
>>>>>>
>>>>>>
>>>>>> Why are you tagging the artifacts containing other projects with the
>>>>>> version number of kolla, instead of their own version numbers and some
>>>>>> sort of incremented build number?
>>>>>
>>>>>
>>>>> This is what we do in Kolla and I'd say logistics and simplicity of
>>>>> implementation. Tags are more than just information for us. We have to
>>>>
>>>>
>>>> But for a user consuming the image, they have no idea what version of
>>>> nova is in it because the version on the image is tied to a different
>>>> application entirely.
>>>
>>>
>>> That's easy enough to check tho (just docker exec into container and
>>> do pip freeze). On the other hand you'll have information that "this
>>> set of various versions was tested together" which is arguably more
>>> important.
>>>
>>>>> deploy these images and we have to know a tag. Combine that with clear
>>>>> separation of build phase from deployment phase (really build phase is
>>>>> entirely optional thanks to dockerhub), you'll end up with either
>>>>> automagical script that will have to somehow detect correct version
>>>>> mix of containers that works with each other, or hand crafted list
>>>>> that will have 100+ versions hardcoded.
>>>>>
>>>>> Incremental build is hard because builds are atomic and you never
>>>>> really know how many times images were rebuilt (also local rebuilt vs
>>>>> dockerhub-pushed rebuild will cause collisions in tags).
>>>>>
>>>>>> Doug
>>>>>>
>>>>>>
>>>>>> __________________________________________________________________________
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>>>>>
>>>>>
>>>>
>>>>
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>>>
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>
>
> --
> @flaper87
> Flavio Percoco
>
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