need multihash info in glance user, admin guides

[Brian Rosmaita]

The user guide and admin guide need info about the secure "multihash" feature. Both need to describe the idea of the self-describing secure hash. Additionally:

admin guide: the os_hash_algo is operator-configurable; explain how

user guide: the os_hash_algo value can be passed to hashlib to obtain a digest algorithm to validate a download

Current sources for this info are:
(1) description of os_hash_value, os_hash_algo in the api-ref
(2) the multihash spec: https://specs.openstack.org/openstack/glance-specs/specs/rocky/implemented/glance/multihash.html
(3) rocky release notes: https://docs.openstack.org/releasenotes/glance/rocky.html

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/754969

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/755075

[OpenStack Infra (hudson-openstack)]

Change abandoned by Sean McGinnis (<email address hidden>) on branch: master
Review: https://review.opendev.org/755075
Reason: Looks like you accidentally submitted a new patch.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Pragathi Marampudi (<email address hidden>) on branch: master
Review: https://review.opendev.org/754969
Reason: Due to some conflicts this commit is abandoned

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/755215

[OpenStack Infra (hudson-openstack)]

Change abandoned by Sean McGinnis (<email address hidden>) on branch: master
Review: https://review.opendev.org/755215

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/755338

[Pragathi Marampudi (pragathi93)]

Hi Sean,

All the old commits are abandoned due to some conflicts.

https://review.opendev.org/755338

this is the commit where I have added patches based on the comments.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/glance/+/755338
Committed: https://opendev.org/openstack/glance/commit/438758db2feeb59d75d6432b84e449df52ba84d6
Submitter: "Zuul (22348)"
Branch: master

commit 438758db2feeb59d75d6432b84e449df52ba84d6
Author: pragathi93 <email address hidden>
Date: Wed Sep 30 13:21:03 2020 +0530

    Add multihash info in glance documentation

    New docs added for os_hash_algo in user guide and admin guide.

    Change-Id: Id78be3935998b9c5acdd0706393117e892e5ab59
    Closes-bug:#1871419

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/glance 26.0.0.0b3 development milestone.