Beyond Metering - Extending Ceilometer

Etherpad: http://etherpad.openstack.org/grizzly-ceilometer-beyond-metering

Over the past few months, numerous request have been made to the Ceilometer project to extend its scope from just metering to more monitoring or alerting. This causes quite a few challenges but as we are instrumenting more and more openstack component to extract data from them, it makes sense to think on how we could extend our capabilities over time.

CloudWatch type functionality
- what granularity of data is needed
- should we collect data the same way
- should we store collected data in our database
- what other components would be needed
Alerting type functionality
- what granularity of data is needed
- should we collect data the same way
- should we store collected data in our database
- what other components would be needed
Other types?

What is the difference between monitoring and metering?

metering

used by a billing system which is a part of the deployment
has a fixed interval (normally 15 min - 5 min)
the data must be persistent
it is important that the data comes from a trusted source (not spoofed)

monitoring

can be used by anyone (real user)
variable interval (set by the user) as low as 1 min
data can expire (deleted after a week or two)
data can be user generated or from a trusted source (configurable)
alarms can be configured to trigger notifications

What are alarms?

The purpose of Alarms is to notify a user when a meter matches a certain criteria.

Some examples

"Tell me when the maximum disk utilization exceeds 90%"
"Tell me when the average CPU utilization exceeds 80% over 120 seconds"
"Tell me when my web app is becoming unresponsive" (loadbalancer latency meter)
"Tell me when my httpd daemon dies" (custom user script that checks daemon health)

How can you use Alarms

Create an alarm

{
 'period': '300',
 'eval_periods': '2',
 'meter': 'CPUUtilization',
 'function': 'average',
 'operator': 'gt',
 'threshold': '50'
 'resource_id': 'inst-002',
 'source': 'OS/compute',
 'alarm_actions': ['rpc/my_notify_topic', 'http://bla.com/bla'],
 'ok_actions': ['rpc/my_notify_topic']
}

This will check the "CPUUtilization" meter events every 300sec and if the average CPUUtilization was > 50% (for inst-002) for both of the last 2 300sec periods then it will send an rpc notification on the "my_notify_topic" topic and post the alarm details to http://bla.com/bla.

Then when the alarm goes below this level it will do the "ok_actions".

Why integrate them into one project?

one statistics api
have one vibrant community rather that two that are less so
code reuse

EfficientMetering/GrizzlySummit/BeyondMetering