[LBaaS] Deletion of associated-to-pool(s) health monitor should fail

[Rami Vaknin]

Version
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Havana on rhel

Description
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It's possible to delete health monitor while they are associated to one or more pools, I think that this should be prohibited, and dissociation from pool should be required first.

[Samuel Bercovici (samuelb)]

As already discussed in the Havana summit, the current model is very prone to errors.
For example, if the delete fails on one of the association deletes, what would be the correct behavior
a. roll back the deletion - difficult to implement
b. don't delete the HM, until the erogenous association are handled
Also as the association deletion is a-sync, I am not sure that the HM deletion behavior is correct.

Last, update on HM error handling suffers from a similar issue when an error is encountered.

In Havana a change to the model was discussed without eventualy anything happening, we can discuss again at the ice house summit.

[Eugene Nikanorov (enikanorov)]

Sam, so basically you agree that this behavior should be changed?
Then we'll just prohibit HM deletion if it is associated.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/53821

[Mark McClain (markmcclain)]

As a temporary measure, I think enacting this restriction makes sense. Long term, we should be able to delete a health monitor and Neutron should handle it properly.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/53821
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=a1de76d1407952572cfe081c4872d7a6127995b3
Submitter: Jenkins
Branch: master

commit a1de76d1407952572cfe081c4872d7a6127995b3
Author: Oleg Bondarev <email address hidden>
Date: Thu Oct 24 16:53:55 2013 +0400

    LBaaS: check for associations before deleting health monitor

    Need to prohibit health monitor deletion if it has associations with
    pools. Given that pools may belong to different lbaas drivers the process
    of monitor deletion becomes complex and unreliable since association
    deletion may fail on any single driver.

    DocImpact

    Closes-Bug: #1243129
    Change-Id: I27c20e7a5be8433f90569534ecf838e33027cb00