wiki:InfoService
Last modified 9 years ago Last modified on 05/22/09 15:23:54

Info Service

The Info Service is a dCache Component that provides a summary of a dCache instance. It collects information from various sources within dCache; by storing these values it provides a common service to discover information about a running dCache instance.

Availability of info service information

The information collected by the info service is available interactively via the admin interface in a variety of formats.

The output is also available in XML format via the HTTP admin webpage with the base path /info; for example, http://example.org:2288/info. Selecting only a subtree of the available information is possible by by expressing the subpath within the URI; for example, to select only information about a poolgroup called ops the following URI may be queried: http://example.org:2288/info/poolgroups/ops.

Running the info service

To run the service, the info domain must be started on a dCache node. There is no restriction on which node the info domain shall run; however, for efficiency, running the info domain and the http domain on the same node will improve performance for web-based queries.

The info service collects data periodically. When started, it will have no information initially. Over the course of a few minutes, more information will be collected until all information is available.

If the info service is not running, web pages that have a path starting /info, will return with an HTTP 503 error message. The message text will indicate that the info service was not discovered. To fix this problem, simply start the info service on a dCache node.

Dependencies and Uses

We recommend running the web interface (httpDomain) to allow easy access to the information.

This component is needed by the Info Provider.