docker-exporter

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docker-exporterLightweight Docker metrics for ARM64 & cgroup v2

A tiny Rust Prometheus exporter for Docker containers — about 7 MiB of RAM, 7 to 30 times less CPU than cAdvisor on ARM64, no privileged mode.

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Memory reads zero on a Pi?
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docker-exporter
🎯

The working set docker stats shows

usage − inactive_file on cgroup v2, usage − cache on v1: the same number `docker stats` reports, under cAdvisor's metric name.

🪶

~7 MiB RAM, ~10 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.

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Drop-in for cAdvisor

cAdvisor-compatible metric names — plugs into an existing Prometheus scrape, and most Grafana dashboards need no rewrite.

⚡

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
~10 MB
image (musl + distroless)
<1%
CPU at steady state
2
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 ​

cAdvisor watches the whole host. It runs privileged with five host mounts and keeps walking the cgroup tree on a timer, whether anyone scrapes it or not. On a busy 8-core ARM64 host it used 30 times docker-exporter's CPU and 84 times its memory to report the same containers (benchmark →).

docker-exporter does one job. It reads the Docker stats API when Prometheus scrapes, computes the working set the way docker stats does on both cgroup versions, talks to the socket read-only and runs non-root.

Memory reading zero on a Pi? That's the boot configuration, and it hits every tool alike, cAdvisor and docker-exporter included. One flag fixes it →

docker-exporter vs cAdvisor ​

Dimensiondocker-exportercAdvisor
Image size (arm64)10.3 MB (3.4 MB to pull)63.7 MB (27.7 MB to pull)
RAM (quiet Pi 5 / busy Rock 5B+)4.2 / 5.1 MiB22.5–35.6 / 128–429 MiB
CPU (same hosts, share of one core)0.13 / 0.67%0.87–1.72 / 10.5–20.4%
Privileged containerNo (socket read-only)Yes
ScopeDocker containersContainers + host + processes + hardware

Measured side by side on a Raspberry Pi 5 on 2026-09-28, docker-exporter 1.6.0 against cAdvisor v0.60.6 — see the benchmark and its method →.

Already running cAdvisor and happy with it? Keep it. Want a smaller footprint on an SBC? See the full comparison →