DeUnhealth

Restart your unhealthy containers safely

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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.

Environment variables

Environment variable Default Possible values Description
LOG_LEVEL info debug, info, warning, error Logging level
HEALTH_SERVER_ADDRESS 127.0.0.1:9999 Valid address Health server listening address
TZ 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

GitHub

https://github.com/qdm12/deunhealth