api-ref: descriptions for the various host fields in server GET response are useless

[Matt Riedemann]

This came up in a review for the mistaken use of the hypervisor_hostname field in the server GET response:

https://review.openstack.org/#/c/446685/2/nova/tests/functional/regressions/test_bug_1671648.py@149

Looking at the API ref:

https://developer.openstack.org/api-ref/compute/?expanded=show-server-details-detail#id25

There are three 'host' related fields in the response:

1. hostId - The ID of the host.
2. OS-EXT-SRV-ATTR:host - The host name. Appears in the response for administrative users only.
3. OS-EXT-SRV-ATTR:hypervisor_hostname - The hypervisor host name. Appears in the response for administrative users only.

The hostId is an obfuscated id for the hostname in the guest (server instance).

The 'host' is the name of the compute host that the nova-compute service is running on. This comes from the 'host' configuration option value in nova.conf.

The 'hypervisor_hostname' is the hostname of the hypervisor, provided by the compute driver, which in most cases is the same as 'host' *except* in the case of Ironic in which case it's the Ironic node name.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/446761

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/446761
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=261e7e3c5e4ee2b403f5c887bb75a8527a367135
Submitter: Jenkins
Branch: master

commit 261e7e3c5e4ee2b403f5c887bb75a8527a367135
Author: melanie witt <email address hidden>
Date: Thu Mar 16 22:16:10 2017 +0000

    Improve descriptions for hostId, host, and hypervisor_hostname

    The current descriptions for hostId, host, and hypervisor_hostname are
    vague, so this adds more detail to make them more understandable.

    Closes-Bug: #1673593

    Change-Id: Id3ea9bbfe59a47b24e3584cf16b5a556007e58ea

[OpenStack Infra (hudson-openstack)]

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