Apollo Testing

This page documents how the Xrootd monitoring is integrated to Apollo

Motivation

Currently all the monitoring messages are sent to Active MQ. In the future Active MQ will be replaced by Apollo, a refactoring of AMQ.

Message redirection

The following pictures shows how the redirection is done.

1. The consumer are sending messages directly to gridmsg007 (AMQ) on port 6162. For our three application being monitored (ie. FAX, AAA and WLCG), we are interested in 5 data source.

• /topic/xrdpop.fax_popularity
• /topic/xrdpop.uscms_popularity
• /topic/xrdpop.eosa_popularity
• /topic/xrootd.ALICE

(eos cms is not here yet).

2. A redirector has been implemented to "copy" all this topics to Apollo. To be sure to not loose any messages, virtual queue have been setup. In addition, using queue instead of topic allow us to load balanced the redirector.

• /queue/Consumer.dashb-redirector.xrdpop.eosa_popularity
• /queue/Consumer.dashb-redirector.xrdpop.fax_popularity
• /queue/Consumer.dashb-redirector.xrdpop.uscms_popularity
• /queue/Consumer.dashb_wlcg.xrootd.ALICE

This step creates 4 topics on apollo ( the same as in AMQ).

3. The last step consist to consume from this Apollo topic through durable subscription (equivalent to Virtual queue in AMQ). The same topic can be used for both XRootD monitoring and WLCG Transfers Dashboard. The following list describe which application used which durable subscription.

• WLCG Transfers Dashboard:
  • dashb-wlcg.xrdpop.fax_popularity
  • dashb-wlcg.xrdpop.uscms_popularity
  • dashb-wlcg.xrootd.ALICE
• FAX Monitoring:
  • dashb-atlas.xrdpop.eosa_popularity
  • dashb-atlas.xrdpop.fax_popularity
• AAA Monitoring:
  • dashb-cms.xrdpop.aaa_popularity

Deployement in production

This redirection mechanism is for testing purpose only, when Apollo will be in production, the sysadmin can just run apollo on the port 6162 (ie. AMQ port). This step should be transparent for BOTH producer and consumer as the STOMP protocol is conserved.