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Grafana Loki

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Grafana Loki (or Loki) is a horizontally scalable, multi-tenant log aggregation system that is extremely easy to operate. Loki does not index the contents of the logs, but rather a set of labels for each log stream. Nobl9 users can leverage Loki to query and build metrics on top of their logs.

Grafana Loki parameters and supported features in Nobl9
General support:
Release channel: Stable, Beta
Connection method: Agent
Replay and SLI Analyzer: Not supported
Event logs: Not supported
Query checker: Not supported
Query parameters retrieval: Supported
Timestamp cache persistence: Not supported
Query parameters:
Query interval: 1 min
Query delay: 1 min
Jitter: 15 sec
Timeout: 30 sec
Agent details and minimum required versions for supported features:
Plugin name: n9grafana_loki
Query delay environment variable: GRAFANA_LOKI_QUERY_DELAY
Query parameters retrieval: 0.73.2
Custom HTTP headers: 0.88.0-beta

Creating SLOs with Grafana Loki​

Nobl9 Web​

Follow the instructions below to create your SLOs with Grafana Loki in the UI:

  1. Navigate to Service Level Objectives.

  2. Click .

  3. In step 1 of the SLO wizard, select the Service the SLO will be associated with.

  4. In step 2, select Grafana Loki as the data source for your SLO.

  5. Specify the Metric. You can choose either a Threshold Metric, where a single time series is evaluated against a threshold or a Ratio Metric, which allows you to enter two time series to compare (for example, a count of good requests and total requests).

  6. Choose the Data Count Method for your ratio metric:

  • Non-incremental: counts incoming metric values one-by-one. So the resulting SLO graph is pike-shaped.
  • Incremental: counts the incoming metric values incrementally, adding every next value to previous values. It results in a constantly increasing SLO graph.
  1. Enter a Query, or Good Query and Total Query for the metric you selected.
    Refer to the Query Examples section below for more details.
SLI values for good and total
When choosing the query for the ratio SLI (countMetrics), keep in mind that the values ​​resulting from that query for both good and total:
  • Must be positive.
  • While we recommend using integers, fractions are also acceptable.
    • If using fractions, we recommend them to be larger than 1e-4 = 0.0001.
  • Shouldn't be larger than 1e+20.
  1. In step 3, define a Time Window for the SLO.

  • Rolling time windows are better for tracking the recent user experience of a service.

  • Calendar-aligned windows are best suited for SLOs that are intended to map to business metrics measured on a calendar-aligned basis, such as every calendar month or every quarter.

  1. In step 4, specify the Error Budget Calculation Method and your Objective(s).
  • Occurrences method counts good attempts against the count of total attempts.
  • Time Slicesmethod measures how many good minutes were achieved (when a system operates within defined boundaries) during a time window.
  • You can define up to 12 objectives for an SLO. For more information, check the Composite SLOs Guide.

See the use case example and the SLO calculations guide for more information on the error budget calculation methods.

  1. In step 5, add the Display name, Name, and other settings for your SLO:
  • Create a composite SLO
  • Set notification on data, if this option is available for your data source.
    When activated, Nobl9 notifies you if your SLO hasn't received data or received incomplete data for more than 15 minutes.
  • Add alert policies, labels, and links, if required.
    You can add up to 20 links per SLO.
  1. Click Create SLO.

sloctl​

Sample Grafana Loki threshold SLO
apiVersion: n9/v1alpha
kind: SLO
metadata:
  name: api-server-slo
  displayName: API Server SLO
  project: default
  labels:
    area:
      - latency
      - slow-check
    env:
      - prod
      - dev
    region:
      - us
      - eu
    team:
      - green
      - sales
  annotations:
    area: latency
    env: prod
    region: us
    team: sales
spec:
  description: Example Grafana Loki SLO
  indicator:
    metricSource:
      name: grafana-loki
      project: default
      kind: Agent
  budgetingMethod: Occurrences
  objectives:
    - displayName: Good response (200)
      value: 200
      name: ok
      target: 0.95
      rawMetric:
        query:
          grafanaLoki:
            logql: >-
              sum(sum_over_time({topic="cdc"} |= "kafka_consumergroup_lag" |
              logfmt | line_format "{{.kafka_consumergroup_lag}}" | unwrap
              kafka_consumergroup_lag [1m]))
      op: lte
      primary: true
  service: api-server
  timeWindows:
    - unit: Month
      count: 1
      isRolling: false
      calendar:
        startTime: 2022-12-01T00:00:00.000Z
        timeZone: UTC
  alertPolicies:
    - fast-burn-5x-for-last-10m
  attachments:
    - url: https://docs.nobl9.com
      displayName: Nobl9 Documentation
  anomalyConfig:
    noData:
      alertMethods:
        - name: slack-notification
          project: default

Metrics for Grafana Loki have one mandatory field:

Query examples​

  • Ratio metric for Grafana Loki:
    Good Query:
    count(count_over_time(({app="nobl9", component="ingest", container="ingest container"} | json | line_format "{{.log}}" | json | http_useragent != "ELB-HealthChecker/2.0" | http_status_code >= 200 and http_status_code < 300)[1m]))
    Total Query:
    count(count_over_time(({app="nobl9", component="ingest", container="ingest-container"} | json | line_format "{{.log}}" | json | http_useragent != "ELB-HealthChecker/2.0" | http_status_code > 0)[1m]))

Querying the Grafana Loki server​

Nobl9 calls Loki API every minute to retrieve the log data from the previous minute. Nobl9 aggregates the total number of points to 4 per minute.

caution

Users should refrain from adding duration and Nobl9 will append [1m] to the query.

For a more in-depth look, consult additional resources:
Grafana HTTP APIGrafana Loki documentationIntroduction to PromQLGrafana documentationAgent metricsAgentCreating SLOs via TerraformTerraformCreating agents via TerraformTerraform
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