The Graffiti project was proposed at the Atlanta (Juno) OpenStack summit. Since then the code and concepts have been spread across multiple different OpenStack Projects:

 - Glance Metadata Definition Catalog
    - http://docs.openstack.org/developer/glance/metadefs-concepts.html

 - Searchlight: http://launchpad.net/searchlight

 - Horizon features

* an admin UI for managing the catalog
** (Admin —> Metadata Definitions) (Kilo)

* a widget for associating metadata to different resources
** (Update Metadata action on each row item below)
** admin -> images (Juno)
** admin -> flavors (Kilo)
** admin —> Host Aggregates (Kilo)
** project —> images (Liberty)
** project —> instances (Mitaka)

* The ability to add metadata at launch time
** project —> Launch Instance (ng launch instance enabled) (Mitaka)

LEGACY Graffiti Project Information

At its most basic concept, Graffiti's intent is to enable better metadata collaboration across services and projects for OpenStack users. Graffiti has the initial intent of providing cross service metadata “tagging" and search aggregation for cloud resources.

https://wiki.openstack.org/wiki/Graffiti