DIRAC Configuration¶
The DIRAC Configuration information has a hierarchical structure and can come from different sources. This section describes the main sections of the DIRAC configuration and the way how this information is delivered to the consumers.
Configuration structure¶
The DIRAC Configuration is organized in a tree structure. It is divided in sections, which can also be seen as directories. Each section can contain other sections and options. The options are the leafs in the configuration tree, which contain the actual configuration data.
At the top level of the Configuration tree there are the following sections:
- DIRAC
- This section contains the most general information about the DIRAC installation.
- Systems
- This section provides configuration data for all the DIRAC Systems, their instances and components - services, agents and databases.
- Registry
- The Registry contains information about DIRAC users, groups and communities (VOs).
- Resources
- The Resources section provides description of all the DIRAC computing resources. This includes computing and storage elements as well as descriptions of several DIRAC and third party services.
- Operations
- This section collects various operational parameters needed to run the system.
The top level sections are described in details in dedicated chapters of the guide.
Configuration sources¶
The DIRAC Configuration can be defined in several places with strict rules how the settings are resolved by the clients. The possible configuration data sources are listed below in the order of preference of the option resolution:
- Command line options
For all the DIRAC commands there is option ‘-o’ defined which takes one configuration option setting. For example:
dirac-wms-job-submit job.jdl -o /DIRAC/Setup=Dirac-Production
- Command line argument specifying a CFG file
If a filename with the .cfg extension is passed as an argument to any DIRAC command it will be interpreted as a configuration file. For example:
dirac-wms-job-submit job.jdl my.cfg
- $HOME/.dirac.cfg
- This is the file in the user’s home directory with the CFG format
- $DIRACROOT/etc/dirac.cfg
- This is the configuration file in the root directory of the DIRAC installation
- Configuration Service
- Configuration data available from the global DIRAC Configuration Service
The client needing a configuration option is first looking for it in the command line arguments. If the option is not found, the search continues in the user configuration file, then in the DIRAC installation configuration file and finally in the Configuration Service. These gives a flexible mechanism of overriding global options by specific local settings.