Gnocchi

Owned by Chris Green
Last updated: Aug 23, 2023
8 min read

This component is currently disabled and not available.

 

Gnocchi processes data from Ceilometer and stores the processed data which can be accessed by users. It correlates measurements from Ceilometer to resources and metrics.

Metric: A resource property which can be measured. For example the CPU, memory usage etc.

Resource: These can be instances, volumes, networks etc.

gnocchiclient

The gnocchi command line tool can be installed using pip:

pip install gnocchiclient

This provides the following Openstack commands:

openstack [metric-command] metric aggregates metric archive-policy create metric archive-policy delete metric archive-policy list metric archive-policy show metric archive-policy update metric archive-policy-rule create metric archive-policy-rule delete metric archive-policy-rule list metric archive-policy-rule show metric benchmark measures add metric benchmark measures show metric benchmark metric create metric benchmark metric show metric capabilities list metric create metric delete metric list metric measures add metric measures aggregation metric measures batch-metrics metric measures batch-resources-metrics metric measures show metric resource batch delete metric resource create metric resource delete metric resource history metric resource list metric resource search metric resource show metric resource update metric resource-type create metric resource-type delete metric resource-type list metric resource-type show metric resource-type update metric server version metric show metric status

 

Metrics

Metrics consist of:

  • Name: unique name for the metric

  • Unit (e.g. MB, ns, B/s)

  • Resource ID - where the measurement is from

  • Unique User ID (UUID): Identifies the metric

  • Archive policy: stores and aggregates the measures

Archive policies determine how long aggregates are kept and how they are aggregated. The archive policies can be seen using the command:

openstack metric archive-policy list +----------------------+-------------+-----------------------------------------+---------------------+ | name | back_window | definition | aggregation_methods | +----------------------+-------------+-----------------------------------------+---------------------+ | ceilometer-high | 0 | - points: 3600, timespan: 1:00:00, | mean | | | | granularity: 0:00:01 | | | | | - points: 1440, timespan: 1 day, | | | | | 0:00:00, granularity: 0:01:00 | | | | | - points: 8760, timespan: 365 days, | | | | | 0:00:00, granularity: 1:00:00 | | | ceilometer-high-rate | 0 | - points: 3600, timespan: 1:00:00, | rate:mean, mean | | | | granularity: 0:00:01 | | | | | - points: 1440, timespan: 1 day, | | | | | 0:00:00, granularity: 0:01:00 | | | | | - points: 8760, timespan: 365 days, | | | | | 0:00:00, granularity: 1:00:00 | | | ceilometer-low | 0 | - points: 8640, timespan: 30 days, | mean | | | | 0:00:00, granularity: 0:05:00 | | | ceilometer-low-rate | 0 | - points: 8640, timespan: 30 days, | rate:mean, mean | | | | 0:00:00, granularity: 0:05:00 | | +----------------------+-------------+-----------------------------------------+---------------------+

 

This table shows each archive-policy and how the raw datapoints for each metric is stored. As an example, let’s view the detail for one of the archive policies.

To view an archive policy, use the command:

For example:

 

For the archive policy ceilometer-high:

  • The mean is stored for each interval.

  • Stores one hour of data in one second intervals. (3600 data points)

  • Stores one day of data in one minute intervals. (1440 data points)

  • Stores one year of data in one hour intervals. (8760 data points)

To view the list of metrics:

This will show the metrics which have been created/visible to the user.

 

To view the metric resources:

 

To view the properties of a specific metric:

Metrics can be created by the user using the gnocchiclient plugin in the Openstack CLI:

Note: Once a metric has been created, the archive policy attribute for that metric is fixed and cannot be changed.

References:

Gnocchi Documentation: Gnocchi 4.6.1.dev107+g1712a798 documentation

Telemetry Measurements for Train: Measurements — ceilometer 13.1.3.dev7 documentation

Gnocchi Aggregation: How I Learned to Stop Worrying and Love Gnocchi aggregation

Gnocchi Glossary: Glossary — Gnocchi 4.5.1 documentation