Getting User Identity
To start working with the Grid in general and with DIRAC in particular, the user should join some grid Virtual Organization and obtain a Grid Certificate. The procedure to obtain the Grid Certificate depends on the user’s national Certification Authority (CA). The certificate is usually obtained via a Web interface and is downloaded into the user’s Web Browser. To be used with the Grid client software, the certificate should be exported from the Browser into a file in p12 format. After that the certificate should be converted into the pem format and stored in the user home directory. If the DIRAC client software is available, the conversion can be done with the following DIRAC command:
$ dirac-cert-convert.sh <cert_file.p12>
The user will be prompted for the password used while exporting the certificate and for the pass phrase to be used with the user’s private key. Do not forget it !
Registration with DIRAC
Users are always working in the Grid as members of some User Community. Therefore, every user must be registered with the Community DIRAC instance. You should ask the DIRAC administrators to do that, the procedure can be different for different communities.
Once registered, a user becomes a member of one of the DIRAC user groups. The membership in the group determines the user rights for various Grid operations. Each DIRAC installation defines a default user group to which the users are attributed when the group is not explicitly specified.
Users authenticate with DIRAC services, and therefore with the Grid services that DIRAC expose via “proxies”, which you can regard as a product of personal certificates.
There are two major differences between certificates and proxies:
certificates are signed by a CA, while proxies can be signed by a certificate and/or by another proxy
proxies can have extra token embedded (like macaroon of Google)
DIRAC uses RFC proxies, following an RFC standard (https://www.ietf.org/rfc/rfc3820.txt).
Before a user can work with DIRAC, the user’s certificate proxy should be initialized and uploaded to the DIRAC ProxyManager Service. This is achieved with a simple command:
In this case the user proxy with the default DIRAC group will be generated and uploaded. If another non-default user group is needed, the command becomes:
$ dirac-proxy-init -g <user_group>
user_group is the desired DIRAC group name for which the user is entitled.