Open Stack

On 06/27/2018 03:17 AM, Ghanshyam Mann wrote:
> 
> 
> 
>   ---- On Tue, 26 Jun 2018 23:12:30 +0900 Doug Hellmann <doug at doughellmann.com> wrote ----
>   > Excerpts from Matthew Treinish's message of 2018-06-26 09:52:09 -0400:
>   > > On Tue, Jun 26, 2018 at 08:53:21AM -0400, Doug Hellmann wrote:
>   > > > Excerpts from Andrea Frittoli's message of 2018-06-26 13:35:11 +0100:
>   > > > > On Tue, 26 Jun 2018, 1:08 pm Thierry Carrez, <thierry at openstack.org> wrote:
>   > > > >
>   > > > > > Dmitry Tantsur wrote:
>   > > > > > > [...]
>   > > > > > > My suggestion: tempest has to be compatible with all supported releases
>   > > > > > > (of both services and plugins) OR be branched.
>   > > > > > > [...]
>   > > > > > I tend to agree with Dmitry... We have a model for things that need
>   > > > > > release alignment, and that's the cycle-bound series. The reason tempest
>   > > > > > is branchless was because there was no compatibility issue. If the split
>   > > > > > of tempest plugins introduces a potential incompatibility, then I would
>   > > > > > prefer aligning tempest to the existing model rather than introduce a
>   > > > > > parallel tempest-specific cycle just so that tempest can stay
>   > > > > > release-independent...
>   > > > > >
>   > > > > > I seem to remember there were drawbacks in branching tempest, though...
>   > > > > > Can someone with functioning memory brain cells summarize them again ?
>   > > > > >
>   > > > >
>   > > > >
>   > > > > Branchless Tempest enforces api stability across branches.
>   > > >
>   > > > I'm sorry, but I'm having a hard time taking this statement seriously
>   > > > when the current source of tension is that the Tempest API itself
>   > > > is breaking for its plugins.
>   > > >
>   > > > Maybe rather than talking about how to release compatible things
>   > > > together, we should go back and talk about why Tempest's API is changing
>   > > > in a way that can't be made backwards-compatible. Can you give some more
>   > > > detail about that?
>   > > >
>   > >
>   > > Well it's not, if it did that would violate all the stability guarantees
>   > > provided by Tempest's library and plugin interface. I've not ever heard of
>   > > these kind of backwards incompatibilities in those interfaces and we go to
>   > > all effort to make sure we don't break them. Where did the idea that
>   > > backwards incompatible changes where being introduced come from?
>   >
>   > In his original post, gmann said, "There might be some changes in
>   > Tempest which might not work with older version of Tempest Plugins."
>   > I was surprised to hear that, but I'm not sure how else to interpret
>   > that statement.
> 
> I did not mean to say that Tempest will introduce the changes in backward incompatible way which can break plugins. That cannot happen as all plugins and tempest are branchless and they are being tested with master Tempest so if we change anything backward incompatible then it break the plugins gate. Even we have to remove any deprecated interfaces from Tempest, we fix all plugins first like - https://review.openstack.org/#/q/topic:remove-support-of-cinder-v1-api+(status:open+OR+status:merged)
> 
> What I mean to say here is that adding new or removing deprecated interface in Tempest might not work with all released version or unreleased Plugins. That point is from point of view of using Tempest and Plugins in production cloud testing not gate(where we keep the compatibility). Production Cloud user use Tempest cycle based version. Pike based Cloud will be tested by Tempest 17.0.0 not latest version (though latest version might work).
> 
> This thread is not just for gate testing point of view (which seems to be always interpreted), this is more for user using Tempest and Plugins for their cloud testing. I am looping  operator mail list also which i forgot in initial post.
> 
> We do not have any tag/release from plugins to know what version of plugin can work with what version of tempest. For Example If There is new interface introduced by Tempest 19.0.0 and pluginX start using it. Now it can create issues for pluginX in both release model 1. plugins with no release (I will call this PluginNR), 2. plugins with independent release (I will call it PluginIR).
> 
> Users (Not Gate) will face below issues:
> - User cannot use PluginNR with Tempest <19.0.0 (where that new interface was not present). And there is no PluginNR release/tag as this is unreleased and not branched software.
> - User cannot find a PluginIR particular tag/release which can work with tempest <19.0.0 (where that new interface was not present). Only way for user to make it work is to manually find out the PluginIR tag/commit before PluginIR started consuming the new interface.

In these discussions I always think: how is it solved outside of the openstack 
world. And the solutions seem to be:
1. for PluginNR - do releases
2. for PluginIR - declare their minimum version of tempest in requirements.txt

Why isn't it sufficient for us?

Dmitry

> 
> Let me make it more clear via diagram:
>                                                                                                                                                                   PluginNR                                                                        PluginIR
>      
>                                                          Tempest 19.0.0
>                                                       Add NewInterface                                                               Use NewInterface                                                    Use NewInterface
>   
> 
>                                                         Tempest 18.0.0
>                                                      NewInterface not present                                               No version of PluginNR                                        Unknown version of PluginIR
> 
> 
>    GATE (No Issue as latest things always being tested live ):                                         OK                                                                                           OK
> 
>    User issues:                                                                                                                                     X (does not work)                                                    Hard to find compatible version
> 
> 
> We need a particular tag from Plugins for OpenStack release, EOL of OpenStack release like Tempest does so that user can test their old release Cloud in easy way.
> 
> -gmann
> 
>   >
>   > > As for this whole thread I don't understand any of the points being brought up
>   > > in the original post or any of the follow ons, things seem to have been confused
>   > > from the start. The ask from users at the summit was simple. When a new OpenStack
>   > > release is pushed we push a tempest release to mark that (the next one will be
>   > > 19.0.0 to mark Rocky). Users were complaining that many plugins don't have a
>   > > corresponding version to mark support for a new release. So when trying to run
>   > > against a rocky cloud you get tempest 19.0.0 and then a bunch of plugins for
>   > > various services at different sha1s which have to be manually looked up based
>   > > on dates. All users wanted at the summit was a tag for plugins like tempest
>   > > does with the first number in:
>   > >
>   > > https://docs.openstack.org/tempest/latest/overview.html#release-versioning
>   > >
>   > > which didn't seem like a bad idea to me. I'm not sure the best mechanism to
>   > > accomplish this, because I agree with much of what plugin maintainers were
>   > > saying on the thread about wanting to control their own releases. But the
>   > > desire to make sure users have a tag they can pull for the addition or
>   > > removal of a supported release makes sense as something a plugin should do.
>   >
>   > We don't coordinate versions across projects anywhere else, for a
>   > bunch of reasons including the complexity of coordinating the details
>   > and the confusion it causes when the first version of something is
>   > 19.0.0. Instead, we list the compatible versions of everything
>   > together on a series-specific page on releases.o.o. That seems to
>   > be enough to help anyone wanting to know which versions of tools
>   > work together. The data is also available in YAML files, so it's easy
>   > enough to consume by automation.
>   >
>   > Would that work for tempest and it's plugins, too?
>   >
>   > Is the problem that the versions are not the same, or that some of the
>   > plugins are not being tagged at all?
>   >
>   > Doug
>   >
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