HAProxy OTel metrics reference

This page provides a complete reference for all HAProxy metrics collected via OpenTelemetry, including the haproxyreceiver and Prometheus receiver paths.

Overview

The HAProxy OpenTelemetry integration collects metrics from the HAProxy CSV stats endpoint via the haproxyreceiver. Metrics are organized into two tiers:

Default metrics (17): Collected automatically with default configuration — sufficient for most monitoring use cases
Optional metrics (16): Disabled by default, enabled individually in the receiver metrics section — useful for detailed debugging and capacity planning

When using the NRDOT guided install, you can choose between two configurations:

Optimized (lower ingest): 17 default metrics, 60s collection interval, optimization processors applied
Comprehensive (full detail): 27 metrics (17 default + 10 optional), 15s collection interval

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To enable optional metrics, add them to the metrics section of your haproxy receiver configuration with enabled: true. See Monitor self-hosted HAProxy with OpenTelemetry for configuration details.

Default metrics

These 17 metrics are collected with default configuration (no metrics section needed).

Metric name	Description	Type	Unit
`haproxy.bytes.input`	Total bytes received by the proxy (collected per frontend, backend, and server)	Sum (cumulative)	By
`haproxy.bytes.output`	Total bytes sent by the proxy (collected per frontend, backend, and server)	Sum (cumulative)	By
`haproxy.connections.errors`	Total number of connection errors (backend and server only)	Sum (cumulative)	{errors}
`haproxy.connections.rate`	Number of connections per second over the last elapsed second (frontend only)	Gauge	{connections}/s
`haproxy.connections.retries`	Total number of connection retries (backend and server only)	Sum (cumulative)	{retries}
`haproxy.requests.denied`	Total number of denied requests (frontend and backend)	Sum (cumulative)	{requests}
`haproxy.requests.errors`	Total number of request errors (frontend only)	Sum (cumulative)	{errors}
`haproxy.requests.queued`	Current number of queued requests (backend and server only)	Gauge	{requests}
`haproxy.requests.rate`	Number of HTTP requests per second over the last elapsed second (frontend only)	Gauge	{requests}/s
`haproxy.requests.redispatched`	Total number of request redispatches (backend and server only)	Sum (cumulative)	{requests}
`haproxy.requests.total`	Total number of HTTP requests received (frontend and backend)	Sum (cumulative)	{requests}
`haproxy.responses.denied`	Total number of denied responses (frontend, backend, and server)	Sum (cumulative)	{responses}
`haproxy.responses.errors`	Total number of response errors (backend and server only)	Sum (cumulative)	{errors}
`haproxy.server_selected.total`	Total number of times a server was selected for load balancing (backend and server)	Sum (cumulative)	{selections}
`haproxy.sessions.average`	Average total session time over the last 1024 requests, in seconds (backend and server)	Gauge	s
`haproxy.sessions.count`	Current number of active sessions (frontend, backend, and server)	Gauge	{sessions}
`haproxy.sessions.rate`	Number of sessions per second over the last elapsed second (frontend, backend, and server)	Gauge	{sessions}/s

Optional metrics

These 16 metrics are disabled by default. Enable them individually in your collector configuration by setting enabled: true in the receiver's metrics section.

The NRDOT comprehensive configuration enables the first 10 of these (marked with [C]).

Metric name	Description	Type	Unit
`haproxy.connections.average_time` [C]	Average connection time in seconds (latency monitoring)	Gauge	s
`haproxy.requests.average_time` [C]	Average queue time for requests in seconds	Gauge	s
`haproxy.responses.average_time` [C]	Average response time in seconds	Gauge	s
`haproxy.active` [C]	Number of active servers in a backend	Gauge	{servers}
`haproxy.backup` [C]	Number of backup servers in a backend	Gauge	{servers}
`haproxy.downtime` [C]	Total downtime in seconds	Sum (cumulative)	s
`haproxy.failed_checks` [C]	Total number of failed health checks	Sum (cumulative)	{checks}
`haproxy.weight` [C]	Server weight (used in load balancing decisions)	Gauge	{weight}
`haproxy.sessions.total` [C]	Total cumulative number of sessions	Sum (cumulative)	{sessions}
`haproxy.connections.total` [C]	Total cumulative number of connections	Sum (cumulative)	{connections}
`haproxy.compression.input`	Total number of bytes submitted to the compressor	Sum (cumulative)	By
`haproxy.compression.output`	Total number of bytes emitted by the compressor	Sum (cumulative)	By
`haproxy.compression.bypass`	Total number of bytes that bypassed compression	Sum (cumulative)	By
`haproxy.compression.responses`	Total number of HTTP responses that were compressed	Sum (cumulative)	{responses}
`haproxy.clients.canceled`	Total number of data transfers aborted by the client	Sum (cumulative)	{cancellations}
`haproxy.sessions.limit`	Configured session limit for the proxy	Gauge	{sessions}

Resource attributes

The following resource attributes are attached to all HAProxy metrics, providing context for filtering and grouping.

Attribute	Description	Example value
`haproxy.proxy_name`	Name of the HAProxy proxy (from the frontend/backend/listen section name in haproxy.cfg)	`http_front`, `flask_backends`, `stats`
`haproxy.service_name`	Type identifier or server name: `FRONTEND` for frontend aggregates, `BACKEND` for backend aggregates, or the specific server name for per-server metrics	`FRONTEND`, `BACKEND`, `backend-app-a`, `backend-app-b`
`haproxy.addr`	The stats endpoint URL that was scraped (used as part of entity identifier)	`http://localhost:8404/stats`
`host.id`	Unique identifier of the host (from `/etc/machine-id` on Linux)	`ec23da5ead46571f2c3a9771b093658b`
`host.name`	Hostname of the machine running the collector	`ip-172-31-7-195.ap-southeast-2.compute.internal`
`os.type`	Operating system type	`linux`

Entity identifier: The HAProxy entity in New Relic is synthesized from host.id + haproxy.addr (for example ec23da5ead46571f2c3a9771b093658b:http://localhost:8404/stats).

Prometheus metric mapping

If you're using the Prometheus receiver path, the following table shows how HAProxy Prometheus metric names map to the OTel haproxyreceiver equivalents. Each OTel metric may have multiple Prometheus sources (one per tier: frontend, backend, server).

OTel metric	Prometheus frontend	Prometheus backend	Prometheus server
`haproxy.bytes.input`	`haproxy_frontend_bytes_in_total`	`haproxy_backend_bytes_in_total`	`haproxy_server_bytes_in_total`
`haproxy.bytes.output`	`haproxy_frontend_bytes_out_total`	`haproxy_backend_bytes_out_total`	`haproxy_server_bytes_out_total`
`haproxy.connections.errors`	—	`haproxy_backend_connection_errors_total`	`haproxy_server_connection_errors_total`
`haproxy.connections.rate`	`haproxy_frontend_connections_rate_max`	—	—
`haproxy.connections.retries`	—	`haproxy_backend_retry_warnings_total`	`haproxy_server_retry_warnings_total`
`haproxy.requests.denied`	`haproxy_frontend_requests_denied_total`	`haproxy_backend_requests_denied_total`	—
`haproxy.requests.errors`	`haproxy_frontend_request_errors_total`	—	—
`haproxy.requests.queued`	—	`haproxy_backend_current_queue`	`haproxy_server_current_queue`
`haproxy.requests.rate`	`haproxy_frontend_http_requests_rate_max`	—	—
`haproxy.requests.redispatched`	—	`haproxy_backend_redispatch_warnings_total`	`haproxy_server_redispatch_warnings_total`
`haproxy.requests.total`	`haproxy_frontend_http_requests_total`	`haproxy_backend_http_requests_total`	—
`haproxy.responses.denied`	`haproxy_frontend_responses_denied_total`	`haproxy_backend_responses_denied_total`	`haproxy_server_responses_denied_total`
`haproxy.responses.errors`	—	`haproxy_backend_response_errors_total`	`haproxy_server_response_errors_total`
`haproxy.server_selected.total`	—	`haproxy_backend_loadbalanced_total`	`haproxy_server_loadbalanced_total`
`haproxy.sessions.average`	—	`haproxy_backend_total_time_average_seconds`	`haproxy_server_total_time_average_seconds`
`haproxy.sessions.count`	`haproxy_frontend_current_sessions`	`haproxy_backend_current_sessions`	`haproxy_server_current_sessions`
`haproxy.sessions.rate`	`haproxy_frontend_max_session_rate`	`haproxy_backend_max_session_rate`	`haproxy_server_max_session_rate`

중요

Known limitations of the Prometheus path:

No per-status-code FACET: The haproxyreceiver parses hrsp_* CSV fields into a status_code attribute on haproxy.requests.total. The Prometheus path does not support this — HTTP response code breakdown is available only as separate metrics (haproxy_frontend_http_responses_total{code="2xx"}) not included in the transform config.
Rate metrics are lifetime maximums: haproxy.connections.rate maps to haproxy_frontend_connections_rate_max and haproxy.requests.rate maps to haproxy_frontend_http_requests_rate_max. These are lifetime max values, not instantaneous rates. For true current rates, use the rate() NRQL function on cumulative counter metrics.
~136 Prometheus metrics have no OTel equivalent: HAProxy's Prometheus endpoint exposes ~204 metrics. Only 36 are mapped to the 17 OTel default metrics (across frontend/backend/server tiers). The remainder (process internals, health check details, DNS resolver stats) have no haproxyreceiver equivalent.

Sample NRQL queries

Use these queries to explore your HAProxy metrics in New Relic:

-- Current sessions across all frontends
FROM Metric SELECT latest(haproxy.sessions.count)
FACET haproxy.proxy_name
WHERE haproxy.service_name = 'FRONTEND'

-- Request rate per frontend over time
FROM Metric SELECT average(haproxy.requests.rate)
FACET haproxy.proxy_name
WHERE haproxy.service_name = 'FRONTEND'
TIMESERIES

-- Backend error rate (responses.errors as rate)
FROM Metric SELECT rate(sum(haproxy.responses.errors), 1 second)
FACET haproxy.proxy_name
WHERE haproxy.service_name = 'BACKEND'
TIMESERIES

-- Bytes throughput per backend
FROM Metric SELECT rate(sum(haproxy.bytes.input), 1 minute) AS 'Bytes In/min',
  rate(sum(haproxy.bytes.output), 1 minute) AS 'Bytes Out/min'
FACET haproxy.proxy_name
WHERE haproxy.service_name = 'BACKEND'

-- Average session time per backend (latency indicator)
FROM Metric SELECT average(haproxy.sessions.average)
FACET haproxy.proxy_name
WHERE haproxy.service_name = 'BACKEND'

-- Per-server session count (individual backend servers)
FROM Metric SELECT latest(haproxy.sessions.count)
FACET haproxy.proxy_name, haproxy.service_name
WHERE haproxy.service_name NOT IN ('FRONTEND', 'BACKEND')

-- Queued requests (indicates backend saturation)
FROM Metric SELECT max(haproxy.requests.queued)
FACET haproxy.proxy_name
WHERE haproxy.service_name = 'BACKEND'
TIMESERIES

Next steps

Find and query your HAProxy data — dashboards, NRQL queries, and data navigation
Monitor self-hosted HAProxy — setup for Linux VMs or bare metal
Monitor HAProxy on Kubernetes — automatic pod discovery for containerized environments
Create NRQL alert conditions — set up alerts based on your HAProxy metrics

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