This describes the service dependencies of FTS upon other WLCG services. It tries to describe the impact upon the FTS service of any problems in its dependent services.
Service |
Activities |
Ramification of service interruption |
Criticality |
Oracle database services |
All components of the FTS synchronise on the database. |
If the local DB is unavailable, all components of the FTS service are down. |
Critical |
SRM |
The FTS transfers files between SRMs |
If an SRM is down, the FTS will fail when attempting to transfer the file. FTS retries, but extended SRM downtime will be visible to the user as 'Failed' jobs. |
Critical to overall service. |
MyProxy server in authorised retriever mode ('special FTS' MyProxy setup) |
Required for FTS 1.5 and FTS 2.0 (in legacy mode) to retrieve the user proxy needed for the transfer |
A user proxy is retrieved only once (and retrieved again once it expires 12 hours later). Users already running jobs will have a proxy on the FTS system and can survive until that local proxy expires. New users' jobs will fail immediately. |
Critical for FTS 1.5 and for FTS 2.0 running in legacy mode |
MyProxy server in authorised renewer mode (MyProxy as used by WMS) |
Used by FTS 2.0 (in the new delegation mode) to renew an expired credential. However, the original credential is refreshed (by delegation) on every new job submission (if the credential is due to expire), so it is expected that the FTS 2.0 server will contact MyProxy only infrequently. |
Users who are not continually submitting into the system may have some of their jobs fail if the credential expires (while the job in in the queue) and cannot be renewed. |
Not critical |
VOMS |
Used by FTS 2.0 at the same point as MyProxy (upon renewal of an expired credential). Same issues apply: the credential is refreshed whenever a new job is submitted into the system (if needed) |
The same as MyProxy server |
Not critical |
BDII information service - FTS server |
Not used directly by the server. The SRM endpoints are currently cached by the make-services.xml tool. |
None |
Not critical |
BDII information service - FTS client |
Discovery tool uses BDII to find the relevant FTS server. |
Minimum: the correct server is defined by WLCG policy. Most experiments hardcode the relevant endpoint. |
Not critical |