IaaS和PaaS云系统的UML部署图

Question

I would like to model the following situation using a UML deployment diagram.

A small command and control machine instance is spawned on an Infrastructure as a Service cloud platform such as Amazon EC2 . This instance is in turn responsible for spawning additional instances and providing them with a control script NumberCruncher.py either via something like S3 or directly as a start up script parameter if the program is small enough to fit into that field. My attempt to model the situation using UML deployment diagrams under the working assumption that a Machine Instance is a Node is unsatisfying for the following reasons.

• The diagram seems to suggest that there will be exactly three number cruncher nodes. Is it possible to illustrate a multiplicity of Nodes in a deployment diagram like one would illustrate a multiplicity of object instances using a multi-object . If this is not possible for Nodes then this seems to be a Long Standing Issue
• Is there anyway to show the equivalent of deployment regions / data-centres in the deployment diagram?

Lastly:

What about Platform as a Service? The whole Machine Instance is a Node idea completely breaks down at that point. What on earth do you do in that case? Treat the entire PaaS provider as a single node and forget about the details?

Answer 1

Regarding your first question:

Is there anyway to show the equivalent of deployment regions / data-centres in the deployment diagram?

I generally use Notes for that.

And your second question:

What about Platform as a Service? The whole Machine Instance is a Node idea completely breaks down at that point. What on earth do you do in that case? Treat the entire PaaS provider as a single node and forget about the details?

I would say, yes for your last question. And I suppose you could take more details from the definition of the deployment model and its elements. Specially at the end of this paragraph:

They [Nodes] can be nested and can be connected into systems of arbitrary complexity using communication paths. Typically, Nodes represent either hardware devices or software execution environments .

and

ExecutionEnvironments represent standard software systems that application components may require at execution time.

source: http://www.omg.org/spec/UML/2.5/Beta1/