Allow user to set and retrieve the server Description

Allow user to set and retrieve the server Description

The launchpad blueprint is located at:

https://blueprints.launchpad.net/nova/+spec/user-settable-server-description

Allow users to set the description of a server when it is created, rebuilt, or updated. Allow users to get the server description.

Problem description

Currently, when a server is created, the description is hardcoded to be the server display name. The description cannot be set on a server rebuild.

Users cannot set the description on the server or retrieve the description. Currently, they need to use other fields, such as the server name or meta-data, to provide a description. These are overloading the name and meta-data fields in a way for which they were not designed. A better way to provide a long human-readable description is to use a separate field. The description can be easily viewed in a server list display.

Use Cases

  • The End User wishes to provide a description when creating a server.

  • The End User wishes to provide a description when rebuilding a server. If the user chooses to change the name, a new description may be needed to match the new name.

  • The End User wishes to get the server’s description.

  • The End User wishes to change the server’s description.

Proposed change

  • Nova REST API

    • Add an optional description parameter to the Create Server, Rebuild Server, and Update Server APIs.

      • No default description on Create Server (set to NULL in the database).

      • If a null description string is specified on the server update or rebuild, then the description is set to NULL in the database (description is removed)

      • If the description parameter is not specified on the server update or rebuild, then the description is not changed.

      • An empty description string is allowed.

    • The Get Server Details API returns the description in the JSON response. This can be NULL.

    • The List Details for Servers API returns the description for each server. A description can be NULL.

  • Nova V2 client

    • Add an optional description parameter to the server create method.

    • Add an optional description parameter to the server rebuild method.

    • Add new methods for server set and clear the description. These will implement a new CLI command “nova describe” with the following positional parameters:

      • server

      • description (Pass in “” to remove the description)

    • Return the description on server show method. This can be null.

    • If detail is requested, return the description on each server returned by the server list method. A description can be null.

  • Openstack V2.1 compute client

    • NOTE: Changes to the Openstack V2 compute client will be implemented under a bug report, and not under this spec.

    • Add an optional description parameter to CreateServer.

    • Add an optional description parameter to RebuildServer.

    • Add an optional description parameter to SetServer and UnsetServer.

    • Return the description on ShowServer. This can be null.

    • If detail is requested, return the description on each server returned by the ListServer. A description can be null.

Note: A description field already exists in the database, so the change is to add API/CLI support for setting and getting the description.

Other projects possibly impacted:

  • Horizon could be changed to set and show the server description.

Alternatives

None

Data model impact

None. The database column for description already exists as 255 characters, and is nullable.

REST API impact

Add the following parameter validation:

valid_description_regex_base = '[%s]*'
valid_description_regex = valid_description_regex_base % (
    re.escape(_get_printable()))

description = {
    'type': ['string', 'null'], 'minLength': 0, 'maxLength': 255,
    'pattern': valid_description_regex,
}

Change the following APIs under a new microversion:

Create Server

New request parameter:

Parameter

Style

Type

Description

description(optional)

plain

csapi:string

The server description

Add the description to the json request schema definition:

base_create = {
    'type': 'object',
    'properties': {
        'server': {
            'type': 'object',
            'properties': {
                'name': parameter_types.hostname,
                'description': parameter_types.description,
                'imageRef': parameter_types.image_ref,
                'flavorRef': parameter_types.flavor_ref,
                'adminPass': parameter_types.admin_password,
                'metadata': parameter_types.metadata,
                'networks': {
                    'type': 'array',
                    'items': {
                        'type': 'object',
                        'properties': {
                            'fixed_ip': parameter_types.ip_address,
                            'port': {
                                'type': ['string', 'null'],
                                'format': 'uuid'
                            },
                            'uuid': {'type': 'string'},
                        },
                        'additionalProperties': False,
                    }
                }
            },
            'required': ['name', 'flavorRef'],
            'additionalProperties': False,
        },
    },
    'required': ['server'],
    'additionalProperties': False,
}

Error http response codes:

  • 400 (BadRequest) if the description is invalid unicode, or longer than 255 characters.

Rebuild Server

New request parameter:

Parameter

Style

Type

Description

description(optional)

plain

csapi:string

The server description

Add the description to the json request schema definition:

base_rebuild = {
    'type': 'object',
    'properties': {
        'rebuild': {
            'type': 'object',
            'properties': {
                'name': parameter_types.name,
                'description': parameter_types.description,
                'imageRef': parameter_types.image_ref,
                'adminPass': parameter_types.admin_password,
                'metadata': parameter_types.metadata,
                'preserve_ephemeral': parameter_types.boolean,
            },
            'required': ['imageRef'],
            'additionalProperties': False,
        },
    },
    'required': ['rebuild'],
    'additionalProperties': False,
}

Error http response codes:

  • 400 (BadRequest) if the description is invalid unicode, or longer than 255 characters.

Update Server

New request parameter:

Parameter

Style

Type

Description

description(optional)

plain

csapi:ServerForUpdate

The server description

Add the description to the json request schema definition:

base_update = {
    'type': 'object',
    'properties': {
        'server': {
            'type': 'object',
            'properties': {
                'name': parameter_types.name,
                'description': parameter_types.description,
            },

Response:

  • The update API currently returns the details of the updated server. As part of this, the description will now be returned in the json response.

Error http response codes:

  • 400 (BadRequest) if the description is invalid unicode, or longer than 255 characters.

Get Server Details

Add the description to the JSON response schema definition.

server = {
    "server": {
        "id": instance["uuid"],
        "name": instance["display_name"],
        "description": instance["display_description"],
        "status": self._get_vm_status(instance),
        "tenant_id": instance.get("project_id") or "",
        "user_id": instance.get("user_id") or "",
        "metadata": self._get_metadata(instance),
        "hostId": self._get_host_id(instance) or "",
        "image": self._get_image(request, instance),
        "flavor": self._get_flavor(request, instance),
        "created": timeutils.isotime(instance["created_at"]),
        "updated": timeutils.isotime(instance["updated_at"]),
        "addresses": self._get_addresses(request, instance),
        "accessIPv4": str(ip_v4) if ip_v4 is not None else '',
        "accessIPv6": str(ip_v6) if ip_v6 is not None else '',
        "links": self._get_links(request,
                                 instance["uuid"],
                                 self._collection_name),
    },

Security impact

None

Notifications impact

The notification changes for this spec will be included as part of the implementation of the Versioned Notification API spec: https://review.openstack.org/#/c/224755/

  • The new versioned notification on instance update will include the description.

  • The new versioned notification on instance create will include the description.

  • The new versioned notification on instance rebuild will include the description.

Other end user impact

Changes to python-novaclient and python-openstackclient as described above.

Horizon can add the description to the GUI.

Performance Impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

chuckcarmack75

Other contributors:

none

Work Items

  1. Implement the nova API changes.

  2. Implement the novaclient and openstackclient changes.

Dependencies

None

Testing

  • Nova functional tests

    • Add a description to the tests that use the API to create a server.

      • Check that the default description is NULL.

    • Add a description to the tests that use the API to rebuild a server.

      • Check that the description can be changed or removed.

      • Check that the description is unchanged if not specified on the API.

    • Add a description to the tests that use the API to update a server.

      • Check that the description can be changed or removed.

      • Check that the description is unchanged if not specified on the API.

    • Check that the description is returned as part of server details for an individual server or a server list.

  • Python nova-client and openstack-client. For the client tests and the CLI tests:

    • Add a description to the tests that create a server.

    • Add a description to the tests that rebuild a server.

    • Set and remove the description on an existing server.

    • Check that the description is returned as part of server details for an individual server or a server list.

  • Error cases:

    • The description passed to the API is longer than 255 characters.

    • The description passed to the API is not valid printable unicode.

  • Edge cases:

    • The description passed to the API is an empty string. This is allowed.

Documentation Impact

Documentation updates to:

References

The request for this feature first surfaced in the ML:

http://lists.openstack.org/pipermail/openstack-dev/2015-August/073052.html

History

Revisions

Release Name

Description

Mitaka

Introduced

Mitaka

Re-submitted to add support for description on Rebuild.

Creative Commons Attribution 3.0 License

Except where otherwise noted, this document is licensed under Creative Commons Attribution 3.0 License. See all OpenStack Legal Documents.

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