In order to support vm_workload_consolidation, workload_balance and
workload_stabilization strategis some instance metrics are required.
This patch is adding support for them.
Implementation is based on a prometheus store populated using sg-core
from ceilometer metrics with Pollster source.
- instance_ram_usage: rely on ceilometer_memory_usage metrics created from
ceilometer memory.usage meter.
- instance_ram_allocated: rely on the memory value provided by the
inventory created from nova and placement APIs.
- instance_cpu_usage: rely on ceilometer_cpu metric created from
ceilometer cpu meter. A max value of 100 is set in the query.
- instance_root_disk_size: rely on the `disk` value provided by the
inventory created from nova and placement APIs.
A new parameterer `instance_uuid_label` has been added to the prometheus
datasource configuration to identify the label used to store the value of the
OpenStack instance uuid for eache instance metric in prometheus. Default
value is `resource`.
Change-Id: I2f2b56aa002014e511a5e48398ef1da43fc4f5e2