ironic-specs/specs/liberty/nodes-tagging.rst

Nodes tagging

https://blueprints.launchpad.net/ironic/+spec/nodes-tagging

This blueprint aims to add support for tagging nodes.

Problem description

Ironic should have tags field for every node, which can be used to divide the nodes to some groups. then we can do list by tag to get a group of nodes with same properties like hardware specs.

Proposed change

• Add APIs that allows a user to add, remove, and list tags for a node.
• Add tag filter parameter to node list API to allow searching for nodes based on one or more string tags.

Alternatives

Current chassis object is kind of an alternative for grouping nodes.

Data model impact

A new ironic.objects.tags.TagList object would be added to the object model, and will add a tags field to the node table of type ironic.objects.tags.TagList that would be populated on-demand (i.e. not eager-loaded).

A tag should be defined as a Unicode string no longer than 255 bytes in length.

For the database schema, the following table constructs would suffice :

CREATE TABLE tags (
    resource_id INT(11) NOT NULL PRIMARY KEY,
    tag VARCHAR(255) NOT NULL CHARACTER SET utf8
    COLLATION utf8_ci PRIMARY KEY
);

REST API impact

The tag CRUD operations API extension would look like the following:

Return list of tags for a node :

GET /v1/nodes/{node_id}/tags

returns :

[
    'tag1',
    'tag2'
]

Add set of tags on a node :

POST /v1/nodes/{node_id}/tags

with request body :

[
    'tag1',
    'tag2'
]

Add a single tag on a node :

PUT /v1/nodes/{node_id}/tags/{tag}

Remove a single tag on a node :

DELETE /v1/nodes/{node_id}/tags/{tag}

Get all nodes tags:

GET /v1/nodes/tags

returns :

[
    'tag1',
    'tag2',
    'tag3'
]

The API that would allow searching/filtering of the GET /v1/nodes REST API call would add a tag query parameter:

Get all nodes having a single tag :

GET /v1/nodes?tag={tag}

Get all nodes having both tag A and tag B:

GET /v1/nodes?tag={tag_a}&tag={tag_b}

RPC API impact

None

State Machine Impact

None

Client (CLI) impact

Add tags CRUD operations commands:

• ironic node-list-tags <node uuid>
• ironic node-update-tags <node uuid> <op> <tag>

<op> Operation: 'add' or 'remove'

Add tag-list filtering support to node-list command:

• ironic node-list --tag tag1 --tag tag2

multiple --tag will be used to filter results in an AND expression.

Driver API impact

None

Nova driver impact

The tags information can be used for nova but it's not being considered as part of this spec, and may be addressed at a later time.

Security impact

None

Other end user impact

None

Scalability impact

None

Performance Impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

niu-zglinux

Work Items

• Add tags table with a migration.
• Add DB API layer for CRUD operations on node tags.
• Added DB API layer for node tag-list filtering support.
• Add Tag, TagList objects and a new tags field to Node object.
• Add REST API for CRUD operations on node tags.
• Add REST API for node tag-list filtering support.
• python-ironicclient additions and modifications.

Dependencies

None

Testing

Add unit tests.

Upgrades and Backwards Compatibility

Add a migration script for DB.

Documentation Impact

Ironic API and python-ironicclient will need to be updated to accompany this change.

References

https://blueprints.launchpad.net/nova/+spec/tag-instances