OpenNebula

quote from email by Simon:

I'm looking at scaling OpenNebula and adding some caching, having the TEMPLATE section to be static  where the information would change only ex. when a VM resize operation is done (or at least, not being updated each time the VM is monitored). One could identify each sections "lifetime" ex. :

USER_TEMPLATE = updated on vm.update or when a VM action fails (and the ERROR attribute is updated)
TEMPLATE = updated on vm.resize, attach, detach, etc. operation
MONITOR = updated on each poll (typically LASTPOLL + MONITORING_INTERVAL in oned.conf.. perhaps add a NEXTPOLL attribute to make caching lifetime easier)
HISTORY_RECORDS = updated on VM state changes (one.vm.action) etc.

Then perhaps vm.vmpool could return only the base <VM> attributes (nothing below the USER_TEMPLATE, TEMPLATE, MONITOR) and one would have to call one.vm.info to retrieve the full VM XML.

I understand that would break backward compatibility. But I think it would be a huge improvement to ease caching of the OpenNebula information.