[Openstack-operators] [nova] Should we allow passing new user_data during rebuild?
clint at fewbar.com
Thu Oct 5 16:49:39 UTC 2017
No offense is intended, so please forgive me for the possibly incendiary
nature of what I'm about to write:
VPS is the predecessor of cloud (and something I love very much, and
rely on every day!), and encourages all the bad habits that a cloud
disallows. At small scale, it's the right thing, and that's why I use
it for my small scale needs. Get a VM, put your stuff on it, and keep
it running forever.
But at scale, VMs in clouds go away. They get migrated, rebooted, turned
off, and discarded, often. Most clouds are terrible for VPS compared to
VPS hosting environments.
I'm glad it's working for you. And I think rebuild and resize will stay
and improve to serve VPS style users in interesting ways. I'm learning now
who our users are today, and I'm confident we should make sure everyone
who has taken the time to deploy and care for OpenStack should be served
by expanding rebuild to meet their needs.
You can all consider this my white flag. :)
Excerpts from Tomáš Vondra's message of 2017-10-05 10:22:14 +0200:
> In our cloud, we offer the possibility to reinstall the same or another OS on a VPS (Virtual Private Server). Unfortunately, we couldn’t use the rebuild function because of the VPS‘s use of Cinder for root disk. We create a new instance and inject the same User Data so that the new instance has the same password and key as the last one. It also has the same name, and the same floating IP is attached. I believe it even has the same IPv6 through some Neutron port magic.
> BTW, you wouldn’t believe how often people use the Reinstall feature.
> Tomas from Homeatcloud
> From: Belmiro Moreira [mailto:moreira.belmiro.email.lists at gmail.com]
> Sent: Wednesday, October 04, 2017 5:34 PM
> To: Chris Friesen
> Cc: openstack-operators at lists.openstack.org
> Subject: Re: [Openstack-operators] [nova] Should we allow passing new user_data during rebuild?
> In our cloud rebuild is the only way for a user to keep the same IP. Unfortunately, we don't offer floating IPs, yet.
> Also, we use the user_data to bootstrap some actions in new instances (puppet, ...).
> Considering all the use-cases for rebuild it would be great if the user_data can be updated at rebuild time.
> On Wed, Oct 4, 2017 at 5:15 PM, Chris Friesen <chris.friesen at windriver.com> wrote:
> On 10/03/2017 11:12 AM, Clint Byrum wrote:
> My personal opinion is that rebuild is an anti-pattern for cloud, and
> should be frozen and deprecated. It does nothing but complicate Nova
> and present challenges for scaling.
> That said, if it must stay as a feature, I don't think updating the
> user_data should be a priority. At that point, you've basically created an
> entirely new server, and you can already do that by creating an entirely
> new server.
> If you've got a whole heat stack with multiple resources, and you realize that you messed up one thing in the template and one of your servers has the wrong personality/user_data, it can be useful to be able to rebuild that one server without affecting anything else in the stack. That's just a convenience though.
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