VT-CloudCaps:Contextualization

Contextualization is the process of parameterizing an instance that is created from an image (template). There are at least two aspects to this that need to be considered for a generic solution.

First of all, the mechanism by which contextualization data, sometimes called user-data, is passed to the cloud management layer. All cloud management platforms within FCTF support a mechanism to support contextualization. OCCI does not standardize this, although initial ideas exist.

Secondly, the mechanism to apply the actual contextualization information within the instance. Here, two general approaches can be distinguished. The first is a meta-data server that provides the instance's user-data for download from a hard coded, private IP. The second mechanism provides user-data inside scripts in a mounted disk image that the cloud management platform creates on-the-fly when creating the instance. Typically, each cloud management platform provides these mechanisms exclusively.

Platform	Meta-data service	ISO disk
OpenStack	X
OpenNebula		X
StratusLab
Synefo
WNoDeS

CloudInit

CloudInit is a tool that is installed inside a VM to retrieve user-data and act accordingly. It supports both of the above mentioned mechanisms and can thus transparently support most cloud management frameworks. ...

Interfaces

Interfaces to pass user-data to the cloud instances are available for most platforms and compute interfaces (find different term?).

Platform/Interface	User-Data support	User-data in OCCI
OpenStack	X	in discussion
OpenNebula	X	?
StratusLab	?	?
Synefo	?	?
WNoDeS	?	?