Dvorák,  F.

Filipovic,  J.

Kouril,  D.

Krenek,  A.

Matyska,  L.

Salvet,  Z.

Sitera,  J.

Sustr, Z.

Vocu,  M.

English

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For more information: www.eu-emi.euL&B with MessagingŠustr, Z.; Vocu˚, M.; Sitera, J.; Dvorˇák, F.; Matyska, L.; Kourˇil, D. Salvet, Z.; Krˇenek, A.; Filipovicˇ, J.;CESNETMessaging in EMI and L&BEMI has declared messaging to be the core of its activities and se-lected Apache’s ActiveMQ as its messaging solution. There are threeprincipal areas where messaging is applicable to L&B:Input to L&B – receiving events from grid components. This is arather complex task since it requires cooperation between multipleproduct teams, who need to modify their components to write to mes-saging first. This will be implemented, eventually, but not in the earlyreleases of EMI.Moreover, event delivery puts much emphasis on reliability, which maynot be sufficient in the current deployment of ActiveMQ.Output from L&B – L&B notifications. The relevant code is fully underthe control of the L&B product team, which is ideal for pilot implemen-tations. There are also well-established user groups who have alreadyexpressed interest in receiving L&B notifications over messaging.L&B notifications are a well known feature and transition to the com-mon messaging infrastructure is quite straightforward. The notifica-tion interlogger stores notification messages generated by the L&Bserver and delivers them as soon as the appropriate notification clientconnects, or forwards them directly if the client is already connected.Message tunneling – L&B clients are widely available in gLite-enabled grid elements. Users who currently use L&B to log user tagsfor their jobs could easily log other tags to be exported as ActiveMQmessages. No need to learn about or install ActiveMQ clients.Output from L&B – Delivering Notifications over ActiveMQInteractive RegistrationExamples given bellow show how to register to receive notification messages on all jobs you own (option -O) on every state change (-c).Specification of conditions is the same for both delivery paths. Functionality available as of L&B 3.0 (released with EMI-1Kebnekaise).Legacyglite-lb-notify new -O -cglite-lb-notify receive <NotifID>ActiveMQglite-lb-notify new -O -c -a x-msg://<topic>Then use your favorite client to listen for messages on <topic>.Note that notification registrations are not permanent. You need to renew them regularly by calling glite-lb-notify refresh <NotifID>to confirm that you are still interested in receiving the messages. View the status of your registration in your browser using the NotifID as URL.Also please note that in the context of EGI.eu, all topic names (<topic>) must start with prefix grid.emi.Dashboards, Grid Monitoring ServicesIt is possible to configure L&B nodes to make registration to receive notifications automatically on installation and maintain that registrationpermanently. Dashboard teams are welcome to contact the L&B Product Team and negotiate automated registration on all L&B nodes.References[1] The Logging and Bookkeeping Subsystem, http://egee.cesnet.cz/cs/JRA1/LB/[2] EMI Messaging, https://twiki.cern.ch/twiki/bin/view/EMI/EMIMessagingContact: L&B Product TeamE-mail: emi-lb@metacentrum.cz

https://twiki.cern.ch/twiki/bin/view/EMI/EMIMessaging Contact: L&B Product Team E-mail: emi-lb@metacentrum.cz

The Logging and Bookkeeping Subsystem,

LB with Messaging

https://zenodo.org/record/6685/files/UF11-messaging.pdf

LB with Messaging

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