Hash ring is stale after new conductor added

[Jim Rollenhagen]

A previous commit ( https://review.openstack.org/#/c/120951/ ) introduced a change where the hash ring is cached, and reset on every request. However, it's not actually reset, and adding a conductor does not actually cause that conductor to be added to the local copy of the hash ring on the API services.

To reproduce:

* Spin up an API service, make some request that should go to a conductor (e.g. node-update). Observe expected behavior of "conductor not found that supports driver" or similar.
* Start a conductor service loaded with the driver for that node.
* Make the same node-update request. Observe erroneous behavior of "conductor not found that supports driver" or similar.
* Restart the API service. Make the same node-update request. Observe expected success.

[aeva black (tenbrae)]

Confirmed.

This one is my fault - amongst the various patches to fix the hash ring, I forgot to add a reset() call. Thanks for catching this, Jim!

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/126751
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=d7cc83129966109556df8669aa970ff39fd156ed
Submitter: Jenkins
Branch: master

commit d7cc83129966109556df8669aa970ff39fd156ed
Author: Jim Rollenhagen <email address hidden>
Date: Tue Oct 7 16:24:31 2014 -0700

    Clear hash ring cache in get_topic_for*

    This causes the hash ring to be reset on each API request, avoiding
    an issue where a new conductor never joins the ring until the API
    service is restarted.

    Closes-Bug: 1378570

    Change-Id: Ic57370163f2f833efab662837036298f29f4ca90

[Dmitry Tantsur (divius)]

Are we backporting it for J?

[Jim Rollenhagen (jim-rollenhagen)]

Yes, we are.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: proposed/juno
Review: https://review.openstack.org/126984

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/126984
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=3807e9447634c5ce6d9f65cac48ddc9bc0f9d295
Submitter: Jenkins
Branch: proposed/juno

commit 3807e9447634c5ce6d9f65cac48ddc9bc0f9d295
Author: Jim Rollenhagen <email address hidden>
Date: Tue Oct 7 16:24:31 2014 -0700

    Clear hash ring cache in get_topic_for*

    This causes the hash ring to be reset on each API request, avoiding
    an issue where a new conductor never joins the ring until the API
    service is restarted.

    Closes-Bug: 1378570

    Change-Id: Ic57370163f2f833efab662837036298f29f4ca90

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/128965