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==========================================
Configurable hostnames for physical nodes
==========================================

https://blueprints.launchpad.net/fuel/+spec/node-naming

Configure the hostnames of the slave nodes that Fuel will deploy based on
custom naming convention.


Problem description
===================

The name that is visible in the UI/CLI/API for the node is NOT what is applied
as the hostname when the node is deployed. The hostname is dynamically
generated (i.e. node-1 .. node-n).
New mechanism should has possibility changing hostname before provision
process to enable customers to access the device for updates, security checks,
etc. and prevent confusion.


Proposed change
===============

This spec proposes to extend UI, fuel-cli and nailgun API as well in
order to use custom hostnames prior provisioning stage.

* New field 'setup hostname' should be added to the UI node settings part
* New field should has ability to forbid to rename node after provisioning
* Extend node essence with new hostname field in nailgun API
  extend nailgun node validation API
  based on custom naming convention checks

* Extend fuel-cli to support to set up hostname
  for example::

    fuel node --node-id 15 --set-hostname node-3

Alternatives
------------

None

Data model impact
-----------------

Node model will include hostname field in nailgun

REST API impact
---------------

NodeValidator should be extended to handle incorrect node's hostname format and
duplicates of hostnames within a cluster as well.
In case when hostname is not set for node hostname will generated by standard
method (node-1...etc)

Upgrade impact
--------------

After upgrade to 7.0 version hostname field will be updated to current
generated node hostname:
In this case will used standard hostname generation method (node-$ID)

Security impact
---------------

None

Notifications impact
--------------------
None

Other end user impact
---------------------

End user gets ``--set-hostname`` additional option via CLI, that not required
for changes. Deployed env can work properly with default values.

End user gets new optional field in UI node settings.
Where hostname can be changed


Performance Impact
------------------

None

Plugin impact
-------------

None

Other deployer impact
---------------------

None

Developer impact
----------------

None

Infrastructure impact
---------------------

None


Implementation
==============

Assignee(s)
-----------

Primary assignee:
  Ivan Ponomarev

Developer:
  Artur Svechnikov

QA:
  Dmirtry Kruglov

Design Review:
  Evgeny Li

Work Items
----------

* Forbid to change node hostname after provisioning
* Extend Fuel UI node settings to add new field hostname
* Extend fuel-cli to use ``--set-hostname`` option
* Modify NodeValidation API of Nailgun
* Modify nailgun node object, node db model
* Modify Upgrade process to add node hostname field
* Modify Nailgun unit tests to test functional of hostname logic
* Write a documentation


Dependencies
============

None


Testing
=======

* Acceptance criteria:

- Admin user can specify a custom hostname to be applied as the hostname
  for a node, via Fuel CLI or Fuel UI
- Admin user can set custom hostname only before the node provisioning
- If a custom node hostname is not provided, the default mechanism of
  autogenerating node hostnames (i.e. 'node-1', etc.) is used
- Custom node hostname is validated to have the proper hostname format
  and not to duplicate existing hostnames in the cluster
- On upgrade to MOS 7.0 the new hostname attribute is filled in the default
  mechanism of autogenerating node hostnames (i.e. 'node-1', etc.)

 **Automated testing scenario**

Set custom node hostname for a node via CLI:

1. Set a new hostname for a node via Fuel CLI
2. Provision and deploy the node
3. Run Network check
4. Connect remotely to the node and verify that the new hostname is applied
5. Run OSTF tests set

 **Manual testing scenario**

Set custom node hostname for a node via Fuel UI:

1. Set a new hostname for a node via Fuel UI
2. Deploy the changes
3. Run Network check
4. Connect remotely to the node and verify that the new hostname is applied
5. Run OSTF tests set


Documentation Impact
====================

* A note should be added to Fuel Deployment Guide to describe the possibility
  to specify custom node hostname.


References
==========

None