The problem: a Pi running containers, and no history
Raspberry Pis are great for home automation, hobby projects and lightweight services. Once you run several Docker containers on one, though, you lose track of what the box is doing. Is it out of memory? Is the SD card or SSD nearly full? Did a container stop answering overnight? SSH-ing in to run docker stats gives you a snapshot, not history or alerts.
Step 1: install the Sentinely agent
The Sentinely agent supports ARM64, which covers a Raspberry Pi 4 or 5 running a 64-bit OS. In Sentinely, open Pulse → Add server, choose Linux, generate an agent API key, and run the displayed command on the Pi:
curl -fsSL https://sentinely.app/install.sh | sudo bash -s -- --key YOUR_API_KEYThe installer selects the right binary for the CPU architecture and verifies its checksum before installing. The Pi appears in your dashboard after its first report.
The agent reports host-level metrics: CPU, memory, disk, network, load, services, processes and open ports. It does not break usage down per container. For that, docker stats on the Pi is still the quickest tool.
Step 2: add an uptime check for each exposed container
If a container serves a web UI or API (Home Assistant, Pi-hole, a small app), add a Ping monitor for its URL. You get a down alert when it stops answering and a recovery notice when it comes back. The target must be reachable from the internet, so this works for services you publish through a tunnel or reverse proxy.
Step 3: add heartbeats for scheduled containers
Backups, sync jobs and scrapers fail silently. Create a heartbeat monitor in Sentinely, then make the job report in when it succeeds:
0 3 * * * docker run --rm my-backup && curl -fsS -X POST -H "Content-Type: application/json" -d '{"status":"ok"}' https://sentinely.app/api/beat/YOUR_TOKENIf the heartbeat doesn't arrive within the expected interval plus a grace period, Sentinely alerts you by email or webhook. Read more about heartbeat monitoring.
Why not Prometheus and Grafana?
Prometheus, node_exporter, cAdvisor and Grafana work on a Pi, but they use memory and storage that a small board doesn't have to spare, and you have to maintain them. Sentinely runs a single lightweight agent on the Pi and keeps the dashboards and alerting off the device.
FAQ
Q: Can I see metrics for each Docker container?
A: Not today. Sentinely monitors the host, and you can cover each container's availability with uptime checks and heartbeats.
Q: How do alerts work?
A: Server threshold alerts go to email, Slack or an HTTPS webhook. Uptime and heartbeat monitors send both a failure alert and a recovery notice.
Q: Is there a free plan?
A: No. Plans start at $19/month and every plan begins with a 14-day trial. See pricing.