This webservice provides live data on Docker containers. It takes data from the Linux kernel control groups and from the namespace of the container and expose them through a HTTP API.

The solution is still a work in progress.

From environment

• PORT: port to bind (4244 by default)
• DOCKER_URL: docker endpoint (http://127.0.0.1:4243 by default)
• REFRESH_TIME: number of second between CPU/net refresh (1 by default)
• PROC_DIR: mountpoint for procfs (default to /proc)
• RUNNER_DIR: directory of runner, process to run in namespaces of containers, (default to /usr/bin)
• CGROUP_DIR: mountpoint of cgroups (default to /sys/fs/cgroup)
• CGROUP_SOURCE: "docker" or "systemd" (docker by default) docker: /sys/fs/cgroup/:cgroup/memory/docker systemd: /sys/fs/cgroup/:cgroup/memory/system.slice/docker-#{id}.slice
• DEBUG: output of debugging information (default "false", switch to "true" to enable)

Run from docker:

docker run -v /sys/fs/cgroup:/host/cgroup:ro         -e CGROUP_DIR=/host/cgroup \
           -v /proc:/host/proc:ro                    -e PROC_DIR=/host/proc \
           -v /var/run/docker.sock:/host/docker.sock -e DOCKER_URL=unix:///host/docker.sock \
           -p 4244:4244 --privileged --pid=host \
           -d scalingo/acadock-monitoring

--pid=host: The daemon has to find the real /proc/#{pid}/ns directory to enter a namespace
--privileged: Acadock has to enter the other containers namespaces

• Memory consumption (in bytes)

  GET /containers/:id/mem

  Return 200 OK Content-Type: text/plain

• CPU usage (percentage)

  Return 200 OK Content-Type: text/plain GET /containers/:id/cpu

• Network usage (bytes and percentage)

  Return 200 OK Content-Type: application/json GET /containers/:id/net

Léo Unbekandt <leo@scalingo.com>