+1 Makes sense to have pubsub. Inside the java codebase, we could consider a clean and idiomatic lib like guava which is easy to unit test.
http://codingjunkie.net/guava-eventbus/ Then, expose out-of-JVM hooks for any of the popular services people use. -A On May 11, 2012 1:58 PM, "Dean" <cl...@tizatron.com> wrote: > Cross reference to: > > > http://mail-archives.apache.org/mod_mbox/incubator-cloudstack-dev/201204.mbox/browser > > [ from: Marlon Davids ] > < munch > > > 2) How do we monitor VM's that are in Cloudstack when they are in an > isolated VLAN does > > anyone have a clever workaround? > > 3) Has anyone developed a script for parsing and alerting on warning > events in the > > management Log yet? > > I would like to propose cloudstack consider a pub/sub model for event > handling to complement API calls like listEvents. > > Polling can be problematic and sensitive to scaling. > > A simple example would be state change on a physical device. The admin > server can simply publish a message on a network socket indicating that the > device has changed it's state. > > If a subscriber was interested in that device, it could make an api call > to the admin server for state change information for that device only. The > admin server may choose to validate that physical device against the > current state table in the database. > > The API would reply that this node changed it's state from Operational to > Prep For Maintenance. (or whatever the transition state would be) > > The message exchange could be wrapped around vm states, resource > additions/removals etc. > > Using a library like zeromq, a developer can write any number of consumers > in any language they wanted to subscribe to the Event Bus. > > Comments? > > -- > -Dean
