Juju and OS upgrades

[Tom Haddon]

We're currently in the final stages of bringing an openstack instance which will be deployed via Juju. We understand that we can upgrade to Icehouse and that Icehouse will be supported on both precise and trusty. So, presumably we'll be able to do OS upgrades of the Openstack components once we're on Icehouse, trusty is released (or trusty -> next LTS), and we're happy to go ahead with the upgrade.

The question I have is, how does Juju handle the OS being upgraded underneath it?

From discussions with Mark Ramm it seems Juju doesn't support this yet, so registering it as an issue so we have a way of tracking progress on it.

[Curtis Hovey (sinzui)]

These are the factors we need to consider.
1. juju precise and trusty are statically linked, and booth created from the same compiler
2. Both use the cloud-archive, though trusty will pull packages from main/universe
3. Juju (as the the 1.17.4 release candidate I am testing now) supports
   mongodb-server and juju-mongodb
   The policy is to use the one that is present,
   but the os upgrade may switch which on is present.
   If the os upgrade keeps mongodb-server, and it is preferred over juju-mongodb,
   not migration is needed,
   but juju-mongodb will be preferred.

[John A Meinel (jameinel)]

We have had discussions about having a way to upgrade machines from P to T.
However, the charm they want to run should change (cs:precise/mysql to
cs:trusty/mysql). There are a lot of potential issues trying to do an OS
upgrade under a running application, and it seemed out of scope for
something we can get defined before trusty.

John
=:->
On Feb 25, 2014 6:10 PM, "Curtis Hovey" <email address hidden> wrote:

> These are the factors we need to consider.
> 1. juju precise and trusty are statically linked, and booth created from
> the same compiler
> 2. Both use the cloud-archive, though trusty will pull packages from
> main/universe
> 3. Juju (as the the 1.17.4 release candidate I am testing now) supports
> mongodb-server and juju-mongodb
> The policy is to use the one that is present,
> but the os upgrade may switch which on is present.
> If the os upgrade keeps mongodb-server, and it is preferred over
> juju-mongodb,
> not migration is needed,
> but juju-mongodb will be preferred.
>
> --
> You received this bug notification because you are subscribed to juju-
> core.
> https://bugs.launchpad.net/bugs/1284734
>
> Title:
> Juju and OS upgrades
>
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