Comment 0 for bug 1412613

For each polling inetervals, Ceilometer compute agent will trigger nova
client directly to acquire the list of VMs.

However, there's a potential risk that the workload for nova client will
increases proportional to the number of Ceilometer compute agents. In
other word, there's a possibility that thousands of Ceilometer compute
agents will call nova client in a very short time period which may lead
large number of requests to nova client in short time. As a result, the
nova client can not handle so many requests in short time, and Ceilometer
compute agent can't fetch metrics.

So we think it would be better to shuffle agents to send request to Nova
to avoid large number of requests to nova client in short time. This would
be more performance effective and reliable.