Recording rules

Recording aggregation rules primarily improve performance on commonly run queries. Recording rules, which run on a fixed interval and save their results into new time series, ingest raw metric data into the database before reading it. They then produce the aggregated and downsampled metric data, and add it back into the database.

Recording rule attributes

Configure a recording rule with a PromQL statement executed against the metrics data with the result stored in a new time series with a unique metric name. PromQL statements in recording rules can include any PromQL function.

Rule fields:

• prometheus_expr: The PromQL expression to evaluate.

• interval_secs: How often to evaluate the rule. Default is 60s.

• label_policy: Specify label names to add to the output metric. If you attempt to add an existing label, the label isn't added. For example, add (instance123:instance).

• execution_group: The execution group this rule is assigned to. Rules in the same execution group run at intervals. All rules in a group must complete before the rules in that group run again.

  Creating too many rules in an execution group can cause delays in execution of the next iteration. Chronosphere recommends limiting the number of rules in an execution group to 200-300 maximum.

• name: The name of the rule. If metric_name is set, this is the human-readable name. Otherwise, it's the time series to output to.

• metric_name: The time series to output to.

• slug: The slug for the rule. This can't change after rule creation.

See the Recording rule API for a full definition.

Recording rules natively support adding labels to the resultant aggregated metrics. Rollup rules don't support adding labels to aggregated metrics. They also require using either a Prometheus relabel rule, or a derived metric with a label_replace function in conjunction with the rollup rule, to accomplish the same goal.

Due to architectural differences between Chronosphere Observability Platform and Prometheus, defining recording rules is sometimes different, especially for expensive recording rules that span many metrics.

Observability Platform uses a single data store. To enhance performance, use the following recommendations:

• Break up the recording rules to scope to different clusters, or another label that scopes your metrics.
• Use the metric_name field so they all get written back into the same name.

With a Prometheus or Thanos setup, Chronosphere recommends scoping the rules to the local Prometheus server (opens in a new tab) to avoid cross-Prometheus queries.

If you have issues with late-arriving data, consider using rollup rules instead.

View recording rules

Select from the following methods to view your recording rules.

Create or update recording rules

Select from the following methods to create or update recording rules.

chronoctl recording-rules scaffold

Chronoctl example

The following YAML example includes three recording rules that calculate the average rate of increase per second for jobs that contain a value for node. The results display for instance and container as measured over one minute.

This example uses the metric_name field to specify the output name of the time series, and the name field to display the human readable name. For backwards compatibility, the example uses the name field for the time series if metric_name isn't specified, like in the third rule.

api_version: v1/config
kind: RecordingRule
spec:
  name: cpu-usage-seconds-sum-rate-1m
  slug: instance-container-cpu-usage-seconds-sum-rate1m
  prometheus_expr: sum(rate(container_cpu_usage_seconds_total{node=""}[1m])) by (instance,
    container)
  metric_name: instance_container:cpu_usage_seconds:sum_rate1m
  interval_secs: 60
  label_policy:
    add:
      resource: cpu
---
api_version: v1/config
kind: RecordingRule
spec:
  name: network-receive-bytes-sum-rate-1m
  slug: instance-container-network-receive-bytes-sum-rate1m
  metric_name: instance_container:network_receive_bytes:sum_rate1m
  prometheus_expr: sum(rate(container_network_receive_bytes_total{node=""}[1m])) by (instance,
    container)
  interval_secs: 60
  label_policy:
    add:
      resource: network-receive
---
api_version: v1/config
kind: RecordingRule
spec:
  name: instance_container:network_transmit_bytes:sum_rate1m
  slug: instance-container-network-transmit-bytes-sum-rate1m
  prometheus_expr: sum(rate(container_network_transmit_bytes_total{node=""}[1m])) by (instance,
    container)
  interval_secs: 60
  label_policy:
    add:
      resource: network-transmit

Delete recording rules

Select from the following methods to delete a recording rule.

chronoctl recording-rules delete SLUG