Astrogrid Architecture

Astrogrid provides software to fully participate in the Virtual Observatory (VO) both as a user (which is documented on http://www.astrogrid.org) and as a data publisher. This site describes the architecture from the point of view of a data publisher with information about the server-side components in the Astrogrid Software Suite.

Detailed information that might influence the decision to install each individual component is given on separate pages - this page gives a broad overview. In general the Astrogrid components form a coherent suite that is fully compliant with IVOA standards, and would allow a fully functional VO to be built with AstroGrid components alone. However, because the components are fully standards-compliant they will interoperate properly with VO tools and services created by other organisations.

The first decision point comes from categorizing what you want to publish. The two components that allow you to publish to the VO are

  • DSA (Data Set Access) - This component is best suited if you have tabular data stored in a database that you want to publish.
  • CEA (Common Execution Architecture) - This component is suited to publishing "applications" or algorithms - for example theoretical simulations, or special data processing applications.

In order for others in the VO to be able to discover your service you need to publicise it - the component that you need to do this is the Registry, which acts as a sort of "yellow pages" where you can advertise properties of your service by publishing established metadata about the service. It is not always necessary to install a registry if you are able to use someone else's registry to publish your service metadata, however it is often actually more convenient to have a local registry - this choice is discussed in more detail on the registry page.

If you have a very large data set that you intend to publish then it might be a benefit to provide a local VOSpace service that might assist in reducing network traffic to your site. VOSpace is a virtualized storage system, which could be used to store intermediate results in a fashion that means that they are accessible to other VO services, as opposed to a user downloading the results to their desktop computer for instance.

Finally if the data/algorithms that you want to publish should not be publicly accessibly, but rather available only to a select group of users then you might consider installing a community component. This allows the administration of those users as well as providing them with the necessary security tokens (in the form of identity certificates) to interact with secured VO services.

There is a Standards matrix which can help in making a choice also.