[openstack-dev] [oslo] Oslo PTG Summary

Joshua Harlow harlowja at fastmail.com
Thu Mar 8 20:53:01 UTC 2018

Can we get some of those doc links opened.

'You need permission to access this published document.' I am getting 
for a few of them :(

Ben Nemec wrote:
> Hi,
> Here's my summary of the discussions we had in the Oslo room at the PTG.
> Please feel free to reply with any additions if I missed something or
> correct anything I've misrepresented.
> oslo.config drivers for secret management
> -----------------------------------------
> The oslo.config implementation is in progress, while the Castellan
> driver still needs to be written. We want to land this early in Rocky as
> it is a significant change in architecture for oslo.config and we want
> it to be well-exercised before release.
> There are discussions with the TripleO team around adding support for
> this feature to its deployment tooling and there will be a functional
> test job for the Castellan driver with Custodia.
> There is a weekly meeting in #openstack-meeting-3 on Tuesdays at 1600
> UTC for discussion of this feature.
> oslo.config driver implementation: https://review.openstack.org/#/c/513844
> spec:
> https://specs.openstack.org/openstack/oslo-specs/specs/queens/oslo-config-drivers.html
> Custodia key management support for Castellan:
> https://review.openstack.org/#/c/515190/
> "stable" libraries
> ------------------
> Some of the Oslo libraries are in a mature state where there are very
> few, if any, meaningful changes to them. With the removal of the
> requirements sync process in Rocky, we may need to change the release
> process for these libraries. My understanding was that there were no
> immediate action items for this, but it was something we need to be
> aware of.
> dropping support for mox3
> -------------------------
> There was some concern that no one from the Oslo team is actually in a
> position to support mox3 if something were to break (such as happened in
> some libraries with Python 3.6). Since there is a community goal to
> remove mox from all OpenStack projects in Rocky this will hopefully not
> be a long-term problem, but there was some discussion that if projects
> needed to keep mox for some reason that they would be asked to provide a
> maintainer for mox3. This topic is kind of on hold pending the outcome
> of the community goal this cycle.
> automatic configuration migration on upgrade
> --------------------------------------------
> There is a desire for oslo.config to provide a mechanism to
> automatically migrate deprecated options to their new location on
> version upgrades. This is a fairly complex topic that I can't cover
> adequately in a summary email, but there is a spec proposed at
> https://review.openstack.org/#/c/520043/ and POC changes at
> https://review.openstack.org/#/c/526314/ and
> https://review.openstack.org/#/c/526261/
> One outcome of the discussion was that in the initial version we would
> not try to handle complex migrations, such as the one that happened when
> we combined all of the separate rabbit connection opts into a single
> connection string. To start with we will just raise a warning to the
> user that they need to handle those manually, but a templated or
> hook-based method of automating those migrations could be added as a
> follow-up if there is sufficient demand.
> oslo.messaging plans
> --------------------
> There was quite a bit discussed under this topic. I'm going to break it
> down into sub-topics for clarity.
> oslo.messaging heartbeats
> =========================
> Everyone seemed to be in favor of this feature, so we anticipate
> development moving forward in Rocky. There is an initial patch proposed
> at https://review.openstack.org/546763
> We felt that it should be possible to opt in and out of the feature, and
> that the configuration should be done at the application level. This
> should _not_ be an operator decision as they do not have the knowledge
> to make it sanely.
> There was also a desire to have a TTL for messages.
> bug cleanup
> ===========
> There are quite a few launchpad bugs open against oslo.messaging that
> were reported against old, now unsupported versions. Since we have the
> launchpad bug expirer enabled in Oslo the action item proposed for such
> bugs was to mark them incomplete and ask the reporter to confirm that
> they still occur against a supported version. This way bugs that don't
> reproduce or where the reporter has lost interest will eventually be
> closed automatically, but bugs that do still exist can be updated with
> more current information.
> deprecations
> ============
> The Pika driver will be deprecated in Rocky. To our knowledge, no one
> has ever used it and there are no known benefits over the existing
> Rabbit driver.
> Once again, the ZeroMQ driver was proposed for deprecation as well. The
> CI jobs for ZMQ have been broken for a while, and there doesn't seem to
> be much interest in maintaining them. Furthermore, the breakage seems to
> be a fundamental problem with the driver that would require non-trivial
> work to fix.
> Given that ZMQ has been a consistent pain point in oslo.messaging over
> the past few years, it was proposed that if someone does step forward
> and want to maintain it going forward then we should split the driver
> off into its own library which could then have its own core team and
> iterate independently of oslo.messaging. However, at this time the plan
> is to propose the deprecation and start that discussion first.
> CI
> ==
> Need to migrate oslo.messaging to zuulv3 native jobs. The
> openstackclient library was proposed as a good example of how to do so.
> We also want to have voting hybrid messaging jobs (where the
> notification and rpc messages are sent via different backends). We will
> define a devstack job variant that other projects can turn on if desired.
> We also want to add amqp1 support to pifpaf for functional testing.
> Low level messaging API
> =======================
> A proposal for a new oslo.messaging API to expose lower level messaging
> functionality was proposed. There is a presentation at
> https://docs.google.com/presentation/d/1mCOGwROmpJvsBgCTFKo4PnK6s8DkDVCp1qnRnoKL_Yo/edit?usp=sharing
> This seemed to generally be well-received by the room, and dragonflow
> and neutron reviewers were suggested for the spec.
> Kafka
> =====
> Andy Smith gave an update on the status of the Kafka driver. Currently
> it is still experimental, and intended to be used for notifications
> only. There is a presentation with more details in
> https://docs.google.com/presentation/d/e/2PACX-1vQpaSSm7Amk9q4sBEAUi_IpyJ4l07qd3t5T_BPZkdLWfYbtSpSmF7obSB1qRGA65wjiiq2Sb7H2ylJo/pub?start=false&loop=false&delayms=3000&slide=id.p
> testing for Edge/FEMDC use cases
> ================================
> Matthieu Simonin gave a presentation about the testing he has done
> related to messaging in the Edge/FEMDC scenario where messaging targets
> might be widely distributed. The slides can be found at
> https://docs.google.com/presentation/d/1LcF8WcihRDOGmOPIU1aUlkFd1XkHXEnaxIoLmRN4iXw/edit#slide=id.p3
> In short, there is a desire to build clouds that have widely distributed
> nodes such that content can be delivered to users from a location as
> close as possible. This puts a lot of pressure on the messaging layer as
> compute nodes (for example) could be halfway around the world from the
> control nodes, which is problematic for a broker-based system such as
> Rabbit. There is some very interesting data comparing Rabbit with a more
> distributed AMQP1 system based on qpid-dispatch-router. In short, the
> distributed system performed much better for this use case, although
> there was still some concern raised about the memory usage on the client
> side with both drivers. Some followup is needed on the oslo.messaging
> side to make sure we aren't leaking/wasting resources in some messaging
> scenarios.
> For further details I suggest taking a look at the presentation.
> mutable configuration
> ---------------------
> This is also a community goal for Rocky, and Chang Bo is driving its
> adoption. There was some discussion of how to test it, and also that we
> should provide an example of turning on mutability for the debug option
> since that is the target of the community goal. The cinder patch can be
> found here: https://review.openstack.org/#/c/464028/ Turns out it's
> really simple!
> Nova is also using this functionality for more complex options related
> to upgrades, so that would be a good place to look for more advanced use
> cases.
> Full documentation for the mutable config options is at
> https://docs.openstack.org/oslo.config/latest/reference/mutable.html
> The goal status is being tracked in
> https://storyboard.openstack.org/#!/story/2001545
> Chang Bo was also going to talk to Lance about possibly coming up with a
> burndown chart like the one he had for the policy in code work.
> oslo healthcheck middleware
> ---------------------------
> As this ended up being the only major topic for the afternoon, the
> session was unfortunately lightly attended. However, the self-healing
> SIG was talking about related topics at the same time so we ended up
> moving to that room and had a good discussion.
> Overall the feature seemed to be well-received. There is some security
> concern with exposing service information over an un-authenticated
> endpoint, but because there is no authentication supported by the health
> checking functionality in things like Kubernetes or HAProxy this is
> unavoidable. The feature won't be mandatory, so if this exposure is
> unacceptable it can be turned off (with a corresponding loss of
> functionality, of course).
> There was also some discussion of dropping the asynchronous nature of
> the checks in the initial version in order to keep the complexity to a
> minimum. Asynchronous testing can always be added later if it proves
> necessary.
> The full spec is at https://review.openstack.org/#/c/531456
> oslo.config strict validation
> -----------------------------
> I actually had discussions with multiple people about this during the
> week. In both cases, they were just looking for a minimal amount of
> validation that would catch an error such at "devug=True". Such a
> validation might be fairly simple to write now that we have the
> YAML-based sample config with (ideally) information about all the
> options available to set in a project. It should be possible to compare
> the options set in the config file with the ones listed in the sample
> config and raise warnings for any that don't exist.
> There is also a more complete validation spec at
> http://specs.openstack.org/openstack/oslo-specs/specs/ocata/oslo-validator.html
> and a patch proposed at https://review.openstack.org/#/c/384559/
> Unfortunately there has been little movement on that as of late, so it
> might be worthwhile to implement something more minimalist initially and
> then build from there. The existing patch is quite significant and
> difficult to review.
> Conclusion
> ----------
> I feel like there were a lot of good discussions at the PTG and we have
> plenty of work to keep the small Oslo team busy for the Rocky cycle. :-)
> Thanks to everyone who participated and I look forward to seeing how
> much progress we've made at the next Summit and PTG.
> -Ben
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