Envoy Proxy¶

The envoy probe monitors Envoy by scraping its admin interface (/stats?format=prometheus), surfacing server health, listener downstream connections and requests, and per-cluster upstream metrics.

Quick start¶

# probes.d/10-envoy.yaml — each file under probes.d/ is a YAML array of probes
- name: envoy
  type: envoy
  params:
    endpoint: http://localhost:9901

Parameters¶

Parameter	Must set	Default	Description
`endpoint`	In practice	`http://localhost:9901`	Base URL of the admin interface
`interval`	No	`30`	Seconds between collections
`timeout`	No	`10`	Request timeout in seconds
`instance_name`	No	-	Stable identity of this proxy; set it when two envoy probes run on one host

Metrics¶

Metric	Unit	Description
`senhub.envoy.up`	1	1 when the admin `/stats` endpoint responded successfully
`envoy.server.uptime`	s	Time since the Envoy process started
`envoy.server.memory.allocated`	By	Memory currently allocated by the Envoy process
`envoy.listener.downstream.connections.active`	#	Downstream connections currently active across all listeners
`envoy.listener.downstream.connections.active`	{connection}	Active downstream connections per listener
`envoy.cluster.upstream.requests.total`	#	Upstream requests dispatched to cluster members (cumulative)
`envoy.cluster.upstream.connections.total`	#	Upstream connections opened to cluster members (cumulative)

Operational notes¶

The Envoy admin interface is typically bound to 127.0.0.1:9901. If the agent runs on the same host, the default endpoint works without changes.
The admin interface should not be exposed to untrusted networks — it provides access to configuration and health state without authentication.
Cluster-level metrics are tagged with cluster (derived from the envoy_cluster_name Prometheus label).

Metric reference¶

Every metric this probe can emit. Metric is the OpenTelemetry name the OTLP, Prometheus and Zabbix outputs derive theirs from. Name is what a Nagios check and the API metrics= filter match. PRTG channel is the label PRTG shows, placeholders filled from the series' tags.

Metric	Name	PRTG channel	Unit	Description
`senhub.envoy.up`	`senhub.envoy.up`	Envoy Up	#	1 when the Envoy admin interface answered /stats?format=prometheus successfully
`envoy.server.uptime`	`envoy.server.uptime`	Envoy Server Uptime	s	Time since the Envoy process started (seconds)
`envoy.server.memory.allocated`	`envoy.server.memory.allocated`	Envoy Memory Allocated	B	Current memory allocated by the Envoy process
`envoy.server.memory.heap_size`	`envoy.server.memory.heap_size`	Envoy Memory Heap Size	B	Current heap size reported by the Envoy process
`envoy.listener.downstream.connections.total`	`envoy.listener.downstream.connections.total`	Envoy Downstream Connections Total	#	Total downstream connections accepted across all listeners (cumulative)
`envoy.listener.downstream.connections.active`	`envoy.listener.downstream.connections.active`	Envoy Downstream Connections Active	#	Currently active downstream connections across all listeners
`envoy.http.downstream.requests.total`	`envoy.http.downstream.requests.total`	Envoy HTTP Requests Total	#	Total HTTP downstream requests received across all HTTP connection managers (cumulative)
`envoy.cluster.upstream.connections.total`	`envoy.cluster.upstream.connections.total`	Envoy Cluster {cluster} Upstream Connections Total	#	Total upstream connections opened to cluster members (cumulative)
`envoy.cluster.upstream.requests.total`	`envoy.cluster.upstream.requests.total`	Envoy Cluster {cluster} Upstream Requests Total	#	Total upstream requests dispatched to cluster members (cumulative)
`envoy.cluster.upstream.requests.time`	`envoy.cluster.upstream.requests.time`	Envoy Cluster {cluster} Upstream Request Time	ms	Cumulative upstream request latency across all requests to cluster members