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Self-HostingPrometheus Metrics

Prometheus Metrics for Hatchet

This document provides an overview of the Prometheus metrics exposed by Hatchet, setup instructions for the metrics endpoint, and example PromQL queries to analyze them.

Setup

To enable Prometheus metrics for your Hatchet instance, you can set the following environment variables. The corresponding configuration YAML values are mentioned in parentheses. If you are deploying Hatchet in HA mode, these should be set on the grpc, controllers, and scheduler deployments.

⚠️

The global metrics are per-process counters — every engine pod maintains its own values, and different metrics are emitted by different roles. Task-creation counters in particular (hatchet_created_tasks_total and hatchet_tenant_created_tasks) increment on the grpc role, so a scrape that only covers controllers and scheduler will never see them, and example queries that reference created tasks (e.g. Queue Processing Efficiency: Assigned vs Created) cannot be computed. Make sure your scrape configuration targets all engine pods — including any pod running the combined all services — and aggregate the counters across pods (e.g. with sum(...)) when querying.

  • Required

    • SERVER_PROMETHEUS_ENABLED (prometheus.enabled)
      • Default: false
      • Description: Enables or disables the Prometheus metrics HTTP server.
  • Optional

    • SERVER_PROMETHEUS_ADDRESS (prometheus.address)

      • Default: ":9090"
      • Description: The network address and port to bind the Prometheus metrics server to.
    • SERVER_PROMETHEUS_PATH (prometheus.path)

      • Default: "/metrics"
      • Description: The HTTP path at which metrics will be exposed.

Once enabled, you can setup any scraper that supports ingesting Prometheus metrics.

Tenant metrics endpoint

This step requires communication with a service that scrapes Hatchet Prometheus metrics.

To enable the tenant API endpoint you can set the following environment variables:

  • Required

    • SERVER_PROMETHEUS_SERVER_URL (prometheus.prometheusServerURL)
      • Description: The Prometheus server URL.
  • Optional

    • SERVER_PROMETHEUS_SERVER_USERNAME (prometheus.prometheusServerUsername)

      • Description: The username to access the Prometheus instance via HTTP basic auth.
    • SERVER_PROMETHEUS_SERVER_PASSWORD (prometheus.prometheusServerPassword)

      • Description: The password to access the Prometheus instance via HTTP basic auth.

Example environment setup:

export SERVER_PROMETHEUS_ENABLED=true
export SERVER_PROMETHEUS_ADDRESS=":9999"
export SERVER_PROMETHEUS_PATH="/custom-metrics"

Restart your Hatchet server after setting these variables to apply the changes.


Global Metrics

Metric NameTypeDescription
hatchet_queue_invocations_totalCounterThe total number of invocations of the queuer function
hatchet_created_tasks_totalCounterThe total number of tasks created
hatchet_retried_tasks_totalCounterThe total number of tasks retried
hatchet_succeeded_tasks_totalCounterThe total number of tasks that succeeded
hatchet_failed_tasks_totalCounterThe total number of tasks that failed (in a final state, not including retries)
hatchet_skipped_tasks_totalCounterThe total number of tasks that were skipped
hatchet_cancelled_tasks_totalCounterThe total number of tasks cancelled
hatchet_assigned_tasksCounterThe total number of tasks assigned to a worker
hatchet_scheduling_timed_outCounterThe total number of tasks that timed out while waiting to be scheduled
hatchet_rate_limitedCounterThe total number of tasks that were rate limited
hatchet_queued_to_assignedCounterThe total number of unique tasks that were queued and later assigned to a worker
hatchet_queued_to_assigned_time_secondsHistogramBuckets of time (in seconds) spent in the queue before being assigned to a worker
hatchet_reassigned_tasksCounterThe total number of tasks that were reassigned to a worker
hatchet_pubsub_publish_duration_secondsHistogramPublisher-side blocking time of a pub/sub Pub call
hatchet_pubsub_transit_secondsHistogramPub/sub publish-to-delivery latency, from the message’s published_at stamp

The two pub/sub histograms are labelled by kind (the pub/sub backend: rabbitmq, postgres, or nats) and topic_kind; hatchet_pubsub_publish_duration_seconds is additionally labelled by result. Two caveats when comparing backends:

  • Publish duration is how long Pub blocks the caller, not how long the broker took to deliver, and only Postgres waits on the broker at all — it publishes with a query, while NATS buffers in memory and RabbitMQ returns once the frames hit the socket (publisher confirms are not enabled). Expect nats to report the smallest durations and postgres the largest, regardless of how quickly each actually delivers.
  • Transit latency is a difference between two clocks, so it is subject to skew between the publishing and subscribing pods. Messages published by engines that predate the published_at stamp are not observed at all.

Example PromQL Queries

1. Rate of calls to the queuer method
rate(hatchet_queue_invocations_total[5m])
2. Average queue time in milliseconds
# Calculates average queue time over the past 5 minutes, converted to ms
rate(hatchet_queued_to_assigned_time_seconds_sum[5m])
  / rate(hatchet_queued_to_assigned_time_seconds_count[5m])
  * 1e3
3. Success and failure rates
rate(hatchet_succeeded_tasks_total[5m])
rate(hatchet_failed_tasks_total[5m])
4. Queue time distribution (histogram)
sum by (le) (
  rate(hatchet_queued_to_assigned_time_seconds_bucket[5m])
)
5. Rate of tasks created vs. retried
rate(hatchet_created_tasks_total[5m])
rate(hatchet_retried_tasks_total[5m])
6. Task Assignment Rate
rate(hatchet_assigned_tasks[5m])
7. Scheduling Timeout Rate
rate(hatchet_scheduling_timed_out[5m])
8. Rate Limiting Impact
rate(hatchet_rate_limited[5m])
9. Task Completion Ratio (Success vs Total)
rate(hatchet_succeeded_tasks_total[5m])
/
(rate(hatchet_succeeded_tasks_total[5m]) + rate(hatchet_failed_tasks_total[5m]))
10. Task Cancellation Rate
rate(hatchet_cancelled_tasks_total[5m])
11. Task Skip Rate
rate(hatchet_skipped_tasks_total[5m])
12. Queue Processing Efficiency (Assigned vs Created)
rate(hatchet_assigned_tasks[5m]) / rate(hatchet_created_tasks_total[5m])
13. Task Reassignment Rate
rate(hatchet_reassigned_tasks[5m])

Tenant Metrics

Metric NameTypeDescription
hatchet_tenant_workflow_duration_millisecondsHistogramDuration of workflow execution in milliseconds (DAGs and single tasks)
hatchet_tenant_queue_invocationsCounterThe total number of invocations of the queuer function
hatchet_tenant_created_tasksCounterThe total number of tasks created
hatchet_tenant_retried_tasksCounterThe total number of tasks retried
hatchet_tenant_succeeded_tasksCounterThe total number of tasks that succeeded
hatchet_tenant_failed_tasksCounterThe total number of tasks that failed (in a final state, not including retries)
hatchet_tenant_skipped_tasksCounterThe total number of tasks that were skipped
hatchet_tenant_cancelled_tasksCounterThe total number of tasks cancelled
hatchet_tenant_assigned_tasksCounterThe total number of tasks assigned to a worker
hatchet_tenant_scheduling_timed_outCounterThe total number of tasks that timed out while waiting to be scheduled
hatchet_tenant_rate_limitedCounterThe total number of tasks that were rate limited
hatchet_tenant_queued_to_assignedCounterThe total number of unique tasks that were queued and later got assigned to a worker
hatchet_tenant_queued_to_assigned_time_secondsHistogramBuckets of time in seconds spent in the queue before being assigned to a worker
hatchet_tenant_queued_to_assigned_by_workflowCounterThe total number of unique tasks that were queued and later got assigned to a worker, by workflow name
hatchet_tenant_queued_to_assigned_time_seconds_by_workflowHistogramBuckets of time in seconds spent in the queue before being assigned to a worker, by workflow name
hatchet_tenant_reassigned_tasksCounterThe total number of tasks that were reassigned to a worker
hatchet_tenant_used_worker_slotsGaugeThe current number of worker slots being used
hatchet_tenant_available_worker_slotsGaugeThe current number of worker slots available (free)
hatchet_tenant_worker_slotsGaugeThe total number of worker slots (free + used)
hatchet_tenant_used_worker_label_slotsGaugeThe current number of worker slots being used, by worker label pair and slot type
hatchet_tenant_available_worker_label_slotsGaugeThe current number of free worker slots, by worker label pair and slot type
hatchet_tenant_worker_label_slotsGaugeThe total number of worker slots (free + used), by worker label pair and slot type
hatchet_tenant_queue_sizeGaugeThe current number of queued items, by queue and workflow name. Polled from the database every 15 seconds; items queued behind a concurrency strategy are not counted. Safe to sum
hatchet_tenant_additional_metadata_queue_sizeGaugeThe current number of queued items, by queue and additional metadata key-value pair. Only keys prefixed with prom_ are exported (scalar values only). Polled from the database every 15 seconds; an item counts towards every exported key it carries, so do not sum across key values

The hatchet_tenant_*_worker_label_slots metrics expose gauges for each unique worker label (key, value) pair and slot type, using the label_key, label_value, and slot_type Prometheus labels. A worker’s slots count towards every label pair the worker carries, so a worker labeled pool=gpu, region=us-east contributes its slots to both the {label_key="pool", label_value="gpu"} and {label_key="region", label_value="us-east"} series.

The slot_type label separates the worker’s slot pools (e.g. default and durable), which have independent capacities. Filter to the slot type you care about — usually default — when computing utilization; a worker’s large durable slot pool would otherwise mask saturation of its default slots. Summing across slot_type values is safe (the pools are disjoint), unlike summing across label_key values.

⚠️

Because a worker contributes to one series per label key, summing these metrics across different label_key values counts the same slots multiple times. Always filter to a single (label_key, label_value) pair when querying.

⚠️

The metadata queue size gauge only exports additional metadata keys prefixed with prom_ (e.g. prom_pool) — prefix a key to opt it in. Every distinct value of an exported key creates its own Prometheus series, so only prefix keys whose values are low-cardinality (pool names, customer tiers), never per-run identifiers.

Example PromQL Queries

1. Workflow Duration by Tenant and Status
rate(hatchet_tenant_workflow_duration_milliseconds_sum[5m])
by (tenant_id, workflow_name, status)
/
rate(hatchet_tenant_workflow_duration_milliseconds_count[5m])
by (tenant_id, workflow_name, status)
2. Tenant Queue Performance (95th percentile)
histogram_quantile(0.95,
  rate(hatchet_tenant_queued_to_assigned_time_seconds_bucket[5m])
) by (tenant_id)
3. Tenant Error Rate by Workflow
rate(hatchet_tenant_failed_tasks[5m]) by (tenant_id)
/
rate(hatchet_tenant_created_tasks[5m]) by (tenant_id)
4. Tenant Task Throughput
rate(hatchet_tenant_succeeded_tasks[5m]) by (tenant_id)
5. Tenant Retry Rate
rate(hatchet_tenant_retried_tasks[5m]) by (tenant_id)
/
rate(hatchet_tenant_created_tasks[5m]) by (tenant_id)
6. Workflow Duration Distribution by Tenant
sum by (tenant_id, le) (
  rate(hatchet_tenant_workflow_duration_milliseconds_bucket[5m])
)
7. Tenant Rate Limiting Impact
rate(hatchet_tenant_rate_limited[5m]) by (tenant_id)
8. Per-Tenant Queue Utilization
rate(hatchet_tenant_queue_invocations[5m]) by (tenant_id)
9. Tenant Scheduling Timeouts
rate(hatchet_tenant_scheduling_timed_out[5m]) by (tenant_id)
10. Tenant Task Assignment Success Rate
rate(hatchet_tenant_assigned_tasks[5m]) by (tenant_id)
/
rate(hatchet_tenant_created_tasks[5m]) by (tenant_id)
11. Tenant Task Reassignment Rate
rate(hatchet_tenant_reassigned_tasks[5m]) by (tenant_id)
12. Worker Slot Utilization by Label Pair
hatchet_tenant_used_worker_label_slots{label_key="pool", label_value="gpu", slot_type="default"}
/
hatchet_tenant_worker_label_slots{label_key="pool", label_value="gpu", slot_type="default"}
13. Queue Backlog by Additional Metadata Tag
sum(hatchet_tenant_additional_metadata_queue_size{key="prom_pool", value="gpu"}) or vector(0)
14. Queue Latency (p95) by Workflow
histogram_quantile(0.95,
  sum by (workflow_name, le) (
    rate(hatchet_tenant_queued_to_assigned_time_seconds_by_workflow_bucket[5m])
  )
)

The worker slot and queue size gauges are designed to drive autoscalers — see Autoscaling Workers for how to use them with KEDA.

Cross-Tenant Analysis

Example PromQL Queries

1. Top 5 Tenants by Task Volume
topk(5,
  sum by (tenant_id) (
    rate(hatchet_tenant_created_tasks[1h])
  )
)
2. Slowest Workflows Across All Tenants
topk(10,
  rate(hatchet_tenant_workflow_duration_milliseconds_sum[5m])
  /
  rate(hatchet_tenant_workflow_duration_milliseconds_count[5m])
) by (tenant_id, workflow_name)
3. Tenant Resource Consumption Comparison
sum by (tenant_id) (
  rate(hatchet_tenant_workflow_duration_milliseconds_sum[1h])
)
/ 1000 / 60  # Convert to minutes

Integration with Prometheus

This endpoint can be used to configure Prometheus to scrape tenant-specific metrics:

scrape_configs:
  - job_name: "hatchet-tenant-metrics"
    static_configs:
      - targets: ["cloud.onhatchet.run"]
    metrics_path: "/api/v1/tenants/707d0855-80ab-4e1f-a156-f1c4546cbf52/prometheus-metrics"
    scheme: "https"
    authorization:
      credentials: "your-api-token-here"

Note: Replace cloud.onhatchet.run with the URL where your Hatchet instance is hosted.

This provides tenant-isolated metrics that can be scraped directly by Prometheus or consumed by other monitoring tools that support the Prometheus text format.