[openstack-dev] [kolla][nova] Orchiestrated upgrades in kolla

Michał Jastrzębski inc007 at gmail.com
Sat Dec 5 01:51:47 UTC 2015


Hey,

Well, example you describe is similar to a situation "what if my computer
dies when I'm in the middle of an alter database". I'd argue that we should
at least for start assume that operators won't do stupid things
intentionally (but bad things might happen, hence step 0). I don't assume
we'll ever be able to solve this kind of problems, apart from making
restore backup as easy as possible, which fortunately docker allows us to
do.
Also I'd rather start from getting "normal" upgrades ready and keep
improving them.

Cheers,
Michal



On 4 December 2015 at 16:18, Steven Dake (stdake) <stdake at cisco.com> wrote:

> Michal,
>
> It looks pretty good but I want neo-style [1] upgrades.  If someone
> rebuilds a container with a migration, I want to make sure that container
> isn't deployed until nova DB has been upgraded.
>
> Can you work this into your model?
>
> Regards
> -steve
>
> [1] https://www.youtube.com/watch?v=guVAeFs5XwE
>
> From: Michał Jastrzębski <inc007 at gmail.com>
> Reply-To: "openstack-dev at lists.openstack.org" <
> openstack-dev at lists.openstack.org>
> Date: Friday, December 4, 2015 at 1:50 PM
> To: "openstack-dev at lists.openstack.org" <openstack-dev at lists.openstack.org
> >
> Subject: [openstack-dev] [kolla][nova] Orchiestrated upgrades in kolla
>
> Hey guys,
>
> Orchiestrated upgrades is one of our highest priorities for M in kolla, so
> following up after discussion on summit I'd like to suggest an approach:
>
> Instead of creating playbook called "upgrade my openstack" we will create
> "upgrade my nova" instead and approach to each service case by case (since
> all of our running services are in dockers, this is possible).
> We will also make use of image tags as version carriers, so ansible will
> deploy new container only if version tag differs from what we ask it to
> deploy. This will help with idempotency of upgrade process.
>
> So let's start with nova. Upgrade-my-nova playbook will do something like
> this:
>
> 0. We create snapshot of our mariadb-data container. This will affect
> every service, but it's always good to have backup and rollback of db will
> be manual action
>
> 1. Nova bootstrap will be called and it will perform db-migration. Since
> current approach to nova code is add-only we shouldn't need to stop
> services and old services should keep working on newer database. Also for
> minor version upgrades there will be no action here unless there is
> migration.
> 2. We upgrade all conductor at the same time. This should take mere
> seconds since we'll have prebuilt containers
> 3. We will upgrade rest of controller services with using "series: 1" in
> ansible to ensure rolling upgrades.
> 4. We will upgrade all of nova-compute services on it's own pace.
>
> This workflow should be pretty robust (I think it is) and it should also
> provide idempotency.
>
> Thoughts?
>
> Regards,
> Michal
>
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