Overview

A Docker monitor reports whether a named container is running. It checks containers on the machine where the Checkmate server itself runs, using the local Docker daemon.

Note

Docker monitors cannot currently watch containers on a remote host — there is no per-monitor Docker host setting. To monitor services running on other machines, use an HTTP monitor or port monitor against the service, or install the Capture agent for hardware metrics.

Creating a Docker monitor

Navigate to Uptime in the sidebar
Click Create monitor
Select Docker container as the monitor type
Enter the container name or ID
Set the check interval
Click Create monitor

Checkmate matches your input against the containers on the host, in this order: exact container ID, exact container name, then partial ID prefix.

Docker daemon access

Checkmate's server needs access to the Docker daemon on its own host:

Checkmate installed directly on the host: no setup needed — the server uses the default Unix socket at /var/run/docker.sock.
Checkmate running in Docker: mount the host's Docker socket into the Checkmate container by adding this volume to your compose file, otherwise Docker monitors will fail:

volumes:
  - /var/run/docker.sock:/var/run/docker.sock:ro

Warning

Advanced: setting the DOCKER_HOST environment variable (plus TLS variables) on the Checkmate server process redirects all Docker monitors to that daemon. It is read once at startup and applies globally — it is not a per-monitor setting. If you use it over TCP, always use TLS (port 2376) and proper authentication; an unencrypted exposed Docker API is a serious security risk.

Container status

Docker monitors check the container's running state. A container is considered:

Up: Container is running and healthy
Down: Container is stopped, exited, or unreachable

HTTP monitors

Monitor container services via HTTP

Port monitors

Monitor container ports directly

Docker monitors