Stream-Level Retention

By default, the Kloudfuse stack comes installed with stream-level (Metrics, Events, Logs, Traces) retention. These policies can be added in the global.retentionPolicy section of the custom_values.yaml. These are the default settings.

global:  
  retentionPolicy:
    logs:
      default:
        retentionTimeValue: 7
        retentionTimeUnit: DAYS
    metrics:
      default:
        retentionTimeValue: 30
        retentionTimeUnit: DAYS
    events:
      default:
        retentionTimeValue: 30
        retentionTimeUnit: DAYS
    traces:
      default:
        retentionTimeValue: 7
        retentionTimeUnit: DAYS

Record-level Retention

Kloudfuse also supports configuring retention at the record-level for each stream. Currently, only metrics, events, and traces stream are supported.

Note that there are some performance implications when enabling record-level retention policies. It is recommended to only add up to 3 additional policies.

Configuring record-level retention policies require 4 changes in the custom_values.yaml, which will be described in the rest of this document.

Configure Additional Retention Policies

In the global section of the helm values, there is a section called retentionPolicy. This section takes in the name of the stream and a list of retention policies. Similar to the format for the stream-level policy, it takes in a retentionTimeValue and retentionTimeUnit fields. There is also a required name field for each custom policy.

Always add new custom policies to the end. Additionally, do not delete or reorder any existing policy.

The example below shows an example configuration for metrics and logs with default policies and 2 additional policies.

global: 
  retentionPolicy:
    expireRoundUp: 10800000 # 3 hour. Required.
    metrics:
      default:
        retentionTimeValue: 5
        retentionTimeUnit: DAYS
      custom:
        - retentionTimeValue: 7
          retentionTimeUnit: DAYS
          name: prod
        - retentionTimeValue: 14
          retentionTimeUnit: DAYS
          name: staging
    logs:
      default:
        retentionTimeValue: 14
        retentionTimeUnit: DAYS
      custom:
        - retentionTimeValue: 30
          retentionTimeUnit: DAYS
          name: prod
        - retentionTimeValue: 90
          retentionTimeUnit: DAYS
          name: staging
    events: []
    traces: []

Configure Kafka Partitions

The corresponding Kafka partitions for each stream must be adjusted to accommodate the new policies. The helm chart checks that the number of configured partitions are divisible by the number of retention policies (default + custom). In the above example, the Kafka metrics topic requires 3 partitions. This ensures that incoming records are sent to different Kafka partitions.

global: 
  kafkaTopics:
    - name: kf_metrics_topic
      partitions: 3
      replicationFactor: 1

Configure Relabel Rules

Configuration for Metrics, Traces and Event streams

Kloudfuse utilizes relabel rules to attach retention policies to each record. If a record does not match any retention policy specified in the global.retentionPolicy.custom, it defaults to the stream-level retention policy. The relabel rules are added in the ingester.config section of the custom_values.yaml . Refer to Configuration of Relabel Rules for more details on configuring relabel rules. For retention policy, the relabel rules syntax supports a retention action. It has a retention_policy field that specifies which retention policy the rule is for. Similarly, as with the prometheus relabel_config syntax, the source_labels, separator, regex fields are used to match the incoming record.

In the example below, metrics that have env label with prod value are configured with prod retention policy. Metrics that have name prefixed test_app prefix are configured with staging retention policy. Note that the relabel rules are evaluated in order. If record matches both rules, the last one gets priority.

Configuration for Logs stream

Although the relabel rules for logs is very similar to metrics, traces and events streams, there’s still some difference with how the rules are expressed. To configure retention policy staging for any logs from source with sub-string -stag-, you can use the following relabel rule :

For more information on how to define and use use relabel rules for logs stream, please refer to this documentation.

External

Configuration of Retention Policies