From: "Dan Kenigsberg" <danken(a)redhat.com>
To: "VDSM Project Development" <vdsm-devel(a)lists.fedorahosted.org>,
Sent: Wednesday, April 9, 2014 3:01:31 PM
Subject: Re: [vdsm] vdsm sync meeting minutes April 1st, 2014
On Wed, Apr 02, 2014 at 09:29:09AM +0100, danken(a)redhat.com wrote:
> - We had a very (too) heated debate about ignoring failures of
> setDomainRegularRole() in http://gerrit.ovirt.org/24495/
> The pain point is that relying on domain role (master/regular) is
> faulty by design. We cannot avoid the cases where a pool has more than
> one domain with a master role written in its metadata.
> One side argued that oVirt should be fixed to handle this unescapable
> truth, or at least enumerate the places where Vdsm and Engine, both
> current and old, depend on master role uniqueness.
> The other side argued that this is not a priority task, and that we
> should try to "garbage-collect" known-bad master roles as a courtesy
> to people digging into domain metadata, and as a means to lessen the
> problem until we kill the pool concept in the upcoming version.
> I hope that I present the debate fairly enough.
In order to move these two patches forward, how about:
- Limit the usage of the catching-all "except Exception" and replace
it with swalling only the expected IO error
- Add a comment about setDomainRegularRole() being called only as a
courtesy garbage-collection attempt.
- Conduct a survey on whether migrateMaster is used by anyone. No
supported Engine has it, but I there was a suggestion that it was
still expected via the command line.
You don't call masterMigrate directly. It's triggered when you deactivate
the master domain.