DeUnhealth

Restart your unhealthy containers safely

Features

• Restart unhealthy containers marked with deunhealth.restart.on.unhealthy=true label
• Receive Docker events as stream instead of polling periodically
• Doesn't need network for security purposes
• Compatible with amd64, 386, arm64, arm32v7, arm32v6, ppc64le, s390x and riscv64 CPU architectures
• Docker image tags and sizes

Setup

1. Use the following command:

   docker run -d --network none -v /var/run/docker.sock:/var/run/docker.sock qmcgaw/deunhealth

   You can also use docker-compose.yml with:

   docker-compose up -d

2. Set labels on containers:

   • To restart containers if they go unhealthy, use the label deunhealth.restart.on.unhealthy=true

3. You can update the image with docker pull qmcgaw/deunhealth:latest or use one of the tags available. ⚠️ You might want to use tagged images since latest will likely break compatibility until we reach a v1.0.0 release.

Options

Environment variable	Flag	Default	Possible values	Description
DOCKER_HOST	--docker-host	Default Docker socket location	Docker host value	Docker host value such as unix:///var/run/docker.sock or tcp://socket-proxy:2375
LOG_LEVEL	--log-level	info	debug, info, warning, error	Logging level
HEALTH_SERVER_ADDRESS	--health-server-address	127.0.0.1:9999	Valid address	Internal health http server listening address. Nothing to do with restarting unhealthy containers.
TZ	N/A	America/Montreal	string	Timezone

Safety

• The application doesn't need network to reduce the attack surface
• Since Docker is written in Go, the program is also written in Go and uses the official Docker Go API
• The Docker container is based on scratch to reduce the attack surface and only contains the static binary
• The container has to run as root unfortunately 😢

Development

VSCode and Docker

Please refer to the corresponding readme.

Locally

1. Install Go, Docker and Git

2. Install Go dependencies with

   go mod download

3. Install golangci-lint

4. You might want to use an editor such as Visual Studio Code with the Go extension.

Commands available

# Build the binary
go build cmd/app/main.go
# Test the code
go test ./...
# Lint the code
golangci-lint run
# Build the Docker image
docker build -t qmcgaw/deunhealth .

See Contributing for more information on how to contribute to this repository.

TODOs

1. Trigger mechanism such that a container restart triggers other restarts
2. Inject pre-build binary doing a DNS lookup to containers labeled for it and that do not have a healthcheck built in (useful for scratch based images without healthcheck especially)
3. Integration tests in Go instead of shell script