Metrics

Crossplane produces Prometheus style metrics for effective monitoring and alerting in your environment. These metrics are essential for helping to identify and resolve potential issues. This page offers explanations of all these metrics gathered from Crossplane. Understanding these metrics helps you maintain the health and performance of your resources. Please note that this document focuses on Crossplane specific metrics and doesn’t cover standard Go metrics.

To enable the export of metrics it’s necessary to configure the --set metrics.enabled=true option in the helm chart.

1metrics:
2  enabled: true

These Prometheus annotations expose the metrics:

1prometheus.io/path: /metrics
2prometheus.io/port: "8080"
3prometheus.io/scrape: "true"

Crossplane core metrics

The Crossplane pod emits these metrics.

Circuit breaker metrics

The circuit breaker prevents reconciliation thrashing by monitoring and rate-limiting watch events per Composite Resource (XR). Crossplane core emits these metrics to help you identify and respond to excessive reconciliation activity.

All circuit breaker metrics include a controller label formatted as composite/<plural>.<group> (for example, composite/xpostgresqlinstances.example.com), providing visibility per XRD without creating high cardinality from individual XR instances.

circuit_breaker_opens_total

Tracks when a circuit breaker transitions from closed to open state. An increase indicates an XR is receiving excessive watch events and has triggered throttling.

Use this metric to:

• Alert on XRs experiencing reconciliation thrashing
• Identify which XRD types are prone to excessive watch events
• Track the frequency of circuit breaker activations

Example PromQL queries:

1# Rate of circuit breaker opens over 5 minutes
2rate(circuit_breaker_opens_total[5m])
3
4# Count of circuit breaker opens by controller
5sum by (controller) (circuit_breaker_opens_total)

circuit_breaker_closes_total

Tracks when a circuit breaker transitions from open to closed state. This indicates an XR has recovered from excessive watch events and returned to normal operation.

Use this metric to:

• Monitor recovery from reconciliation thrashing

• Verify circuit breakers are closing after cooldown periods

• Track circuit breaker lifecycle

circuit_breaker_events_total

Tracks all watch events processed by the circuit breaker, labeled by result:

• Allowed: Normal operation when circuit is closed - events proceed to reconciliation

• Dropped: Events blocked when circuit is fully open - indicates active throttling

• Halfopen_allowed: Limited probe events when circuit is half-open - circuit is testing for recovery

Use this metric to:

• Track the volume of watch events per XR type
• Detect when the circuit drops events (active throttling)
• Alert on high dropped event rates indicating potential issues
• Understand reconciliation pressure on specific controllers

Example PromQL queries:

 1# Rate of dropped events (active throttling), aggregated per controller
 2sum by (controller) (
 3  rate(circuit_breaker_events_total{result="Dropped"}[5m])
 4)
 5
 6# Percentage of events being dropped
 7sum by (controller) (rate(circuit_breaker_events_total{result="Dropped"}[5m]))
 8/
 9sum by (controller) (rate(circuit_breaker_events_total[5m])) * 100
10
11# Number of replicas per controller currently dropping events
12count by (controller) (
13  rate(circuit_breaker_events_total{result="Dropped"}[5m]) > 0
14)
15
16# Estimated number of circuit breaker opens over 5 minutes
17sum by (controller) (
18  increase(circuit_breaker_opens_total[5m])
19)
20
21# Alert condition: controllers under high watch pressure (severe overload)
22sum by (controller) (
23  rate(circuit_breaker_events_total{result="Dropped"}[5m])
24) > 1

Recommended alerts:

 1# Alert when circuit breaker is consistently dropping events
 2- alert: CircuitBreakerDropRatioHigh
 3  expr: |
 4    (
 5      sum by (controller)(rate(circuit_breaker_events_total{result="Dropped"}[5m]))
 6      /
 7      sum by (controller)(rate(circuit_breaker_events_total[5m]))
 8    ) > 0.2
 9  for: 5m
10  labels:
11    severity: critical
12  annotations:
13    summary: "High circuit breaker drop ratio for {{ $labels.controller }}"
14    description: "More than 20% of events are being dropped by the circuit breaker for {{ $labels.controller }}, indicating sustained overload."
15
16# Alert when circuit breaker opens frequently
17- alert: CircuitBreakerFrequentOpens
18  expr: |
19    sum by (controller) (
20      rate(circuit_breaker_opens_total[5m])
21    ) * 3600 > 6
22  for: 15m
23  labels:
24    severity: warning
25  annotations:
26    summary: "Frequent circuit breaker opens for {{ $labels.controller }}"
27    description: "Circuit breaker for {{ $labels.controller }} is opening more than 6 times per hour, indicating reconciliation thrashing."

For more information on the circuit breaker feature and configuration, see Troubleshooting - Circuit breaker.

Provider metrics

Crossplane providers emit these metrics. All providers built with crossplane-runtime emit the crossplane_managed_resource_* metrics.

Providers expose metrics on the metrics port (default 8080). To scrape these metrics, configure a PodMonitor or add Prometheus annotations to the provider’s DeploymentRuntimeConfig.

Upjet provider metrics

These metrics are only emitted by Upjet-based providers (such as provider-upjet-aws, provider-upjet-azure, provider-upjet-gcp).

Controller-runtime and Kubernetes client metrics

These metrics come from the controller-runtime framework and Kubernetes client libraries. Both Crossplane and providers emit these metrics.