Does Cloud API matter ?


An insightful post by Thorsten of Rightscale. While the post starts with cloud.com’s evolution, what caught my attention was the statement about cloud apis viz: ” … the API itself is more a programming exercise than a fundamental issue, it’s the semantics of the resources behind the API that really matter. Seemingly obscure stuff like: can you reattach a disk volume across datacenters, or can you move an IP address across datacenters, things that deeply affect how one builds redundant services in a particular cloud.” so true …

Couple of observations:

  1. While the API syntax doesn’t matter, the models behind the APIs do matter, because the models determine the flexibility, the agility and the extensibility …
  2. The resources semantics do matter, and I hope the resources exposed via the cloud APIs include not only the compute and storage but also the network as well as the interconnections there of
  3. And the resources semantics need to declarative rather than specific – proper layering of the configuration-provisioning-automation-orchestration functionalities are very important in a cloud infrastructure. The upper layers (and APIs thereof) should be working at the declarative orchestration-automation capabilities (#5 in architecture diagram), dealing with what; with the lower network devices dealing with the how of configuration and provisioning (#4 in the same diagram).  In short, no static configurations, but orchestration and automation based on declarative rules and policies; no early configurations, but just in time configurations based on the state of the cloud applications.
  4. There seems to be two sets of APIs – EC2 style for public clouds and vCloud style for private clouds. I am not sure if this is due to gravity or because of distinct functionality. But in real terms there is no big conceptual or implementation difference between the two … What says thee ?
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