# Revision history [back]

### Can new Ceilometer plugins be loaded without reinstalling ?

Hello,

The task I am working on is to measure VMs spawning time on an OpenStack system. For this, I would like Ceilometer to capture compute.instance.update events, and be able to read the timestamp associated to a state change for a specific VM.

I have read OpenStack documentation on writing Ceilometer agent plugins, and came up with the following (please take note that I am using Havana):

1) To make Nova generate compute.instance.update events, I modified nova.conf file as follows on each Compute node:

notification_driver = nova.openstack.common.notifier.rpc_notifier