nova-status needs to check that placement 1.4 is available for pike

[Matt Riedemann]

In Ocata, nova-compute wouldn't start if placement wasn't available, but it didn't check the version so placement from newton will still work with ocata computes. Also, the filter scheduler will fallback to not using placement if the computes aren't all new enough yet, but even once the computes are upgraded if placement is not the latest and microversion 1.4 isn't available, then the filter scheduler will not find any resource providers and it will result in a NoValidHost error.

For Pike, the fallback code for the older computes has been removed from the filter scheduler:

https://review.openstack.org/#/c/436180/

So we're always calling placement from the filter scheduler. However, we don't enforce a minimum version of placement and we need 1.4 for the filter scheduler to work. We should add a check to the "nova-status upgrade check" command to enforce that placement is running with at least the 1.4 microversion (ocata) before upgrading to Pike.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/441881

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/441881
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=a17851ab0ab1296e587c582523e9421a06e20597
Submitter: Jenkins
Branch: master

commit a17851ab0ab1296e587c582523e9421a06e20597
Author: Roman Podoliaka <email address hidden>
Date: Mon Mar 6 12:45:51 2017 +0200

    nova-status: require placement >= 1.4

    Since Ia1a0066dc30025c02553584a077365b28d8ff80e FilterScheduler will
    no longer fall back to not using placement API. We need to require
    version 1.4 to prevent NoValidHost errors.

    Closes-Bug: #1669433

    Change-Id: I6666cb2f558ed1f4e83f21e0317a206b07c25134

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 16.0.0.0b1 development milestone.