Container-Mon

Get notified when your Docker containers are unhealthy.

Prerequisites

• A notification service supported by Shoutrrr and the required API keys or other configuration for your chosen service (e.g: Telegram, Discord, Slack, Teams etc)

Building

Build the app:

go build

Format:

gofmt -w -s .

Installation

• If you have go installed, you can clone the repository and directly run the go file
• You can download the latest release artifact from GitHub Releases
• If you have Docker installed, you can run the Docker image

Configuration

Configuration can be set via environment variables or command line flags. Command line flags take precedence over environment variables. Only CONTAINERMON_NOTIFICATION_URL (or --notification-url) is mandatory; all other fields are optional.

Usage

Go

go run app.go --notification-url "telegram://token@telegram?channels=channel-1" --fail-limit=1 --cron="*/2 * * * *"

Executable

./container-mon --notification-url "telegram://token@telegram?channels=channel-1" --fail-limit=1 --cron="*/2 * * * *"

Docker

docker run \
  -v /var/run/docker.sock:/var/run/docker.sock \
  -e CONTAINERMON_NOTIFICATION_URL=telegram://token@telegram?channels=channel-1 \
  ghcr.io/rafhaanshah/container-mon:latest

Docker-Compose

services:
  container-mon:
    container_name: container-mon
    image: ghcr.io/rafhaanshah/container-mon:latest
    restart: unless-stopped
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    environment:
      - CONTAINERMON_NOTIFICATION_URL=telegram://token@telegram?channels=channel-1

Troubleshooting

• Docker API version issues: if you get error messages like client version 1.43 is too new. Maximum supported API version is 1.42 then please set the DOCKER_API_VERSION environment variable to the latest version supported by your Docker engine (e.g. DOCKER_API_VERSION=1.42), which you can check by running docker version.
• Notifier issues: please check if your URL works with the Shoutrrr CLI here.

Security Considerations

• It can be considered a security risk to directly map your Docket socket inside a container. A proxy such as Socket-Proxy can be used to give fine-grained access to parts of the Docker API, this application only needs to be able to read a list of running containers ->

  
  docker run \
   -e DOCKER_HOST=tcp://socket-proxy:2375
  ...
  

• This container runs as root by default to access the Docker socket. You may run it as another user that has access to the socket as described here: Running a Docker container as a non-root user ->

  docker run \
  -u $(id -u):$(stat -c '%g' "/var/run/docker.sock") \
  ...
  

License

MIT