docker-exporterCorrect Docker metrics on ARM64 & cgroup v2

A tiny Rust Prometheus exporter for Docker containers — and the fix for cAdvisor's zero-memory bug on Raspberry Pi 5.

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Why cAdvisor breaks on Pi

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🎯

Correct working set

usage − inactive_file on cgroup v2, usage − cache on v1. The exact number cAdvisor reports as zero on ARM64 + cgroup v2.

🪶

~7 MiB RAM, ~9 MB image

A single static Rust binary on distroless/static. Under 1% CPU at steady state — sized for a Raspberry Pi, not a datacenter.

🔒

Read-only & non-root

Mounts the Docker socket read-only and runs as UID 65532. No privileged mode, no cgroup/proc/sys bind mounts.

🔁

Drop-in for cAdvisor

cAdvisor-compatible metric names — plugs into an existing Prometheus scrape and Grafana dashboards with no rewrites.

⚡

No background loop

Stats are fetched per scrape with a 5 s per-container timeout. Every scrape rebuilds all metric families from scratch — no cached or stale metric state between requests.

🧩

Glob container exclusion

EXCLUDE_CONTAINERS with glob patterns (cache-*, *-sidecar). A malformed pattern fails loudly at startup, never silently.

~7 MiB

RAM at idle

~9 MB

image (musl + distroless)

<1%

CPU at steady state

arches: amd64 · arm64

Quick start

bash

docker run -d \
  --name docker-exporter \
  -v /var/run/docker.sock:/var/run/docker.sock:ro \
  -p 9713:9713 \
  --restart unless-stopped \
  ghcr.io/dlepaux/docker-exporter:latest

Then scrape http://localhost:9713/metrics. Full walkthrough in the installation guide.

Why it exists

On a Raspberry Pi 5 (ARM64 + cgroup v2), cAdvisor reports zero for container_memory_working_set_bytes and container_memory_rss — memory dashboards silently lie. It's an upstream-acknowledged bug (cAdvisor #3469, closed "not planned") that persists even after you enable memory cgroups on the Pi.

docker-exporter reads the Docker stats API directly and computes the working set correctly on both cgroup versions. It talks to the socket read-only and runs non-root. Read the full story →

docker-exporter vs cAdvisor

Dimension	docker-exporter	cAdvisor
Image size	~9 MB	~250 MB
RAM (idle, ~10 containers)	~7–10 MiB	~80–150 MiB
cgroup v2 working set on ARM64	Correct	Reports zero — known issue
Privileged container	No (socket read-only)	Yes
Scope	Docker containers	Containers + host + processes + hardware

Numbers are docker-exporter's own reported measurements — see the reproducible benchmark methodology →.

Already running cAdvisor and happy with it? Keep it. Hitting the Pi 5 memory bug, or want a smaller footprint on an SBC? See the full comparison →