Troubleshoot

Where to look first

# systemd status
sudo systemctl status pier

# logs (last 100 lines)
sudo journalctl -u pier -n 100 --no-pager

# live tail
sudo journalctl -u pier -f

Common symptoms

”Port 80 already in use”

Another service (Apache, nginx, a different Traefik) is binding port 80 on the host. Stop it or move it. Pier expects Traefik to own 80 and 443.

Let’s Encrypt fails to issue a cert

• The domain’s A record must resolve to this server before you add the domain in Pier.
• Port 80 must be open to the public internet — ACME HTTP-01 challenges need it.
• Check Traefik logs: docker logs pier-traefik.

Container starts, then exits immediately

• Open the Logs tab on the service. Most image issues show up in the container’s stdout.
• Confirm env vars are set. Missing required env is the most common cause.
• For databases, check disk space on the data volume: df -h.

Dashboard shows 502

• The Pier systemd unit is probably not running. sudo systemctl restart pier.
• If Pier is running but returning 502, check journalctl -u pier -n 200 for panics.

High memory usage

A single Pier process should stay under 50 MB resident. If you see hundreds of MB, one of the managed containers is using it. Open the Memory popup on the dashboard — it breaks memory down per container.

Reporting bugs

File issues at the Pier repo with:

• Pier version (Settings → Updates).
• OS + Docker version.
• 100 lines of journalctl -u pier.
• Steps to reproduce.