[openstack-dev] [nova] readout from Philly Operators Meetup

Matt Riedemann mriedem at linux.vnet.ibm.com
Wed Mar 11 13:47:01 UTC 2015

On 3/11/2015 7:59 AM, Sean Dague wrote:
> The last couple of days I was at the Operators Meetup acting as Nova
> rep for the meeting. All the sessions were quite nicely recorded to
> etherpads here - https://etherpad.openstack.org/p/PHL-ops-meetup
> There was both a specific Nova session -
> https://etherpad.openstack.org/p/PHL-ops-nova-feedback as well as a
> bunch of relevant pieces of information in other sessions.
> This is an attempt for some summary here, anyone else that was in
> attendance please feel free to correct if I'm interpreting something
> incorrectly. There was a lot of content there, so this is in no way
> comprehensive list, just the highlights that I think make the most
> sense for the Nova team.
> =========================
>   Nova Network -> Neutron
> =========================
> This remains listed as the #1 issue from the Operator Community on
> their burning issues list
> (https://etherpad.openstack.org/p/PHL-ops-burning-issues L18). During
> the tags conversation we straw polled the audience
> (https://etherpad.openstack.org/p/PHL-ops-tags L45) and about 75% of
> attendees were over on neutron already. However those on Nova Network
> we disproportionally the largest clusters and longest standing
> OpenStack users.
> Of those on nova-network about 1/2 had no interest in being on
> Neutron (https://etherpad.openstack.org/p/PHL-ops-nova-feedback
> L24). Some of the primary reasons were the following:
> - Complexity concerns - neutron has a lot more moving parts
> - Performance concerns - nova multihost means there is very little
>    between guests and the fabric, which is really important for the HPC
>    workload use case for OpenStack.
> - Don't want OVS - ovs adds additional complexity, and performance
>    concerns. Many large sites are moving off ovs back to linux bridge
>    with neutron because they are hitting OVS scaling limits (especially
>    if on UDP) - (https://etherpad.openstack.org/p/PHL-ops-OVS L142)
> The biggest disconnect in the model seems to be that Neutron assumes
> you want self service networking. Most of these deploys don't. Or even
> more importantly, they live in an organization where that is never
> going to be an option.
> Neutron provider networks is close, except it doesn't provide for
> floating IP / NAT.
> Going forward: I think the gap analysis probably needs to be revisited
> with some of the vocal large deployers. I think we assumed the
> functional parity gap was closed with DVR, but it's not clear in it's
> current format it actually meets the n-net multihost users needs.
> ===================
>   EC2 going forward
> ===================
> Having a sustaninable EC2 is of high interest to the operator
> community. Many large deploys have some users that were using AWS
> prior to using OpenStack, or currently are using both. They have
> preexisting tooling for that.
> There didn't seem to be any objection to the approach of an external
> proxy service for this function -
> (https://etherpad.openstack.org/p/PHL-ops-nova-feedback L111). Mostly
> the question is timing, and the fact that no one has validated the
> stackforge project. The fact that we landed everything people need to
> run this in Kilo is good, as these production deploys will be able to
> test it for their users when they upgrade.
> ============================
>   Burning Nova Features/Bugs
> ============================
> Hierarchical Projects Quotas
> ----------------------------
> Hugely desired feature by the operator community
> (https://etherpad.openstack.org/p/PHL-ops-nova-feedback L116). Missed
> Kilo. This made everyone sad.
> Action: we should queue this up as early Liberty priority item.
> Out of sync Quotas
> ------------------
> https://etherpad.openstack.org/p/PHL-ops-nova-feedback L63
> The quotas code is quite racey (this is kind of a known if you look at
> the bug tracker). It was actually marked as a top soft spot during
> last fall's bug triage -
> http://lists.openstack.org/pipermail/openstack-dev/2014-September/046517.html
> There is an operator proposed spec for an approach here -
> https://review.openstack.org/#/c/161782/
> Action: we should make a solution here a top priority for enhanced
> testing and fixing in Liberty. Addressing this would remove a lot of
> pain from ops.
> Reporting on Scheduler Fails
> ----------------------------
> Apparently, some time recently, we stopped logging scheduler fails
> above DEBUG, and that behavior also snuck back into Juno as well
> (https://etherpad.openstack.org/p/PHL-ops-nova-feedback L78). This
> has made tracking down root cause of failures far more difficult.
> Action: this should hopefully be a quick fix we can get in for Kilo
> and backport.
> =============================
>   Additional Interesting Bits
> =============================
> Rabbit
> ------
> There was a whole session on Rabbit -
> https://etherpad.openstack.org/p/PHL-ops-rabbit-queue
> Rabbit is a top operational concern for most large sites. Almost all
> sites have a "restart everything that talks to rabbit" script because
> during rabbit ha opperations queues tend to blackhole.
> All other queue systems OpenStack supports are worse than Rabbit (from
> experience in that room).
> oslo.messaging < 1.6.0 was a significant regression in dependability
> from the incubator code. It now seems to be getting better but still a
> lot of issues. (L112)
> Operators *really* want the concept in
> https://review.openstack.org/#/c/146047/ landed. (I asked them to
> provide such feedback in gerrit).
> Nova Rolling Upgrades
> ---------------------
> Most people really like the concept, couldn't find anyone that had
> used it yet because Neutron doesn't support it, so they had to big
> bang upgrades anyway.
> Galera Upstream Testing
> -----------------------
> The majority of deploys run with Galera MySQL. There was a question
> about whether or not we could get that into upstream testing pipeline
> as that's the common case.
> 	-Sean

Thanks for writing this up. Etherpads are usually a mess for those not 
involved in creating them so it's always useful to have some summary and 
digestion after the fact.



Matt Riedemann

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