openstack team mailing list archive

[Tim Bell <Tim.Bell@xxxxxxx>]

We should not also forget the documentation for the migration process
itself. We need to have stable documentation (such as perform software
installation, run upgrade script and restart service) while allowing
post-release migration bugs to be resolved (when migration problems are
found in the field). Automated testing can find some problems but the
flexibility of OpenStack configuration would make it likely that there are
other scenarios not covered by the test suite.

Another item are to clearly identify the order in which services can be
upgraded and what are the possibilities for pushing a small part of the
cloud to a more recent version ohile maintaining the majority on the
previous stable release.

This sort of feedback loop is exactly what I hope for from the interaction
between the user and technical  communities.

Since we're Essex based, we've not had to face this yet but Essex to Folsom
will be a good chance for improvements to be included in the core code.

Tim

> -----Original Message-----
> From: openstack-bounces+tim.bell=cern.ch@xxxxxxxxxxxxxxxxxxx
> [mailto:openstack-bounces+tim.bell=cern.ch@xxxxxxxxxxxxxxxxxxx] On Behalf
> Of Jay Pipes
> Sent: 29 August 2012 08:32
> To: openstack@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Openstack] A plea from an OpenStack user
> 
> Ryan, thank you for your excellent and detailed comments about problems
> you encountered during the upgrade process. This is precisely the kind of
> constructive feedback that is needed and desired.
> 
> Someone mentioned automated testing of upgrade paths. This is exactly what
> needs to happen. Hopefully the Tempest folks can work with the CI team in
> the G timeframe to incorporate upgrade path testing for the OpenStack
> components. It likely won't solve ALL the issues -- such as the poor LDAP
port
> in Keystone Light -- but it will at least serve to highlight where the
major issues
> are BEFORE folks run into them. It will also help identify those tricky
things like
> the Glance issue below:
> Glance itself upgraded its data effectively, but failed to produce scripts
to
> modify the Nova image database IDs at the same time.
> 
> Thanks again,
> -jay
> 
> On 08/28/2012 05:26 PM, Ryan Lane wrote:
> > Yesterday I spent the day finally upgrading my nova infrastructure
> > from diablo to essex. I've upgraded from bexar to cactus, and cactus
> > to diablo, and now diablo to essex. Every single upgrade is becoming
> > more and more difficult. It's not getting easier, at all. Here's some
> > of the issues I ran into:
> >
> > 1. Glance changed from using image numbers to uuids for images. Nova's
> > reference to these weren't updated. There was no automated way to do
> > so. I had to map the old values to the new values from glance's
> > database then update them in nova.
> > The mention of testing upgrade paths go 2. Instance hostnames are
> > changed every single release. In bexar and cactus it was the ec2 style
> > id. In diablo it was changed and hardcoded to instance-<ec2-style-id>.
> > In essex it is hardcoded to the instance name; the instance's ID is
> > configurable (with a default of instance-<ec2-style-id>, but it only
> > affects the name used in virsh/the filesystem. I put a hack into
> > diablo (thanks to Vish for that hack) to fix the naming convention as
> > to not break our production deployment, but it only affected the
> > hostnames in the database, instances in virsh and on the filesystem
> > were still named instance-<ec2-style-id>, so I had to fix all libvirt
> > definitions and rename a ton of files to fix this during this upgrade,
> > since our naming convention is the ec2-style format. The hostname
> > change still affected our deployment, though. It's hardcoded. I
> > decided to simply switch hostnames to the instance name in production,
> > since our hostnames are required to be unique globally; however, that
> > changes how our puppet infrastructure works too, since the certname is
> > by default based on fqdn (I changed this to use the ec2-style id).
> > Small changes like this have giant rippling effects in
> > infrastructures.
> >
> > 3. There used to be global groups in nova. In keystone there are no
> > global groups. This makes performing actions on sets of instances
> > across tenants incredibly difficult; for instance, I did an in-place
> > ubuntu upgrade from lucid to precise on a compute node, and needed to
> > reboot all instances on that host. There's no way to do that without
> > database queries fed into a custom script. Also, I have to have a
> > management user added to every single tenant and every single
> > tenant-role.
> >
> > 4. Keystone's LDAP implementation in stable was broken. It returned no
> > roles, many values were hardcoded, etc. The LDAP implementation in
> > nova worked, and it looks like its code was simply ignored when auth
> > was moved into keystone.
> >
> > My plea is for the developers to think about how their changes are
> > going to affect production deployments when upgrade time comes.
> >
> > It's fine that glance changed its id structure, but the upgrade should
> > have handled that. If a user needs to go into the database in their
> > deployment to fix your change, it's broken.
> >
> > The constant hardcoded hostname changes are totally unacceptable; if
> > you change something like this it *must* be configurable, and there
> > should be a warning that the default is changing.
> >
> > The removal of global groups was a major usability killer for users.
> > The removal of the global groups wasn't necessarily the problem,
> > though. The problem is that there were no alternative management
> > methods added. There's currently no reasonable way to manage the
> > infrastructure.
> >
> > I understand that bugs will crop up when a stable branch is released,
> > but the LDAP implementation in keystone was missing basic
> > functionality. Keystone simply doesn't work without roles. I believe
> > this was likely due to the fact that the LDAP backend has basically no
> > tests and that Keystone light was rushed in for this release. It's
> > imperative that new required services at least handle the
> > functionality they are replacing, when released.
> >
> > That said, excluding the above issues, my upgrade went fairly smoothly
> > and this release is *way* more stable and performs *way* better, so
> > kudos to the community for that. Keep up the good work!
> >
> > - Ryan
> >
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