A Docker-in-Docker (DinD) service based on Debian, allowing you to run Docker inside a Docker container. Useful for CI/CD pipelines, development environments, and containerized build systems.

Features

Based on latest stable Debian (13.2-slim)
Out-of-the-box Docker daemon
Optional NVIDIA Container Toolkit for GPU support
Resource limits configured
Healthcheck included
Customizable via environment variables

Quick Start

Copy the example environment file:
```
cp .env.example .env
```
Start the service:
```
docker compose up -d
```

Verify Docker is running inside the container:

docker compose exec dind docker info
docker compose exec dind docker run hello-world

Configuration

Key environment variables (see .env.example for all options):

Variable	Description	Default
`DEBIAN_VERSION`	Debian base image version	`13.2-slim`
`DIND_PORT_OVERRIDE`	Host port for Docker daemon	`2375`
`INSTALL_NVIDIA_TOOLKIT`	Install NVIDIA toolkit during build	`false`
`TZ`	Timezone	`UTC`
`DIND_CPU_LIMIT`	CPU limit	`2.0`
`DIND_MEMORY_LIMIT`	Memory limit	`4G`

GPU Support

To use DinD with GPU support:

Set INSTALL_NVIDIA_TOOLKIT=true in .env
Use the gpu profile:
```
docker compose --profile gpu up -d
```

Or use the dedicated GPU service:

docker compose up -d dind-gpu

Security Considerations

⚠️ Important: This service runs in privileged mode, which grants the container extensive access to the host system. Only use this in trusted environments.

Privileged mode is required for DinD to function
Docker daemon exposed on port 2375 without TLS (development only)
For production, enable TLS by setting DOCKER_TLS_CERTDIR=/certs

Volume

dind-data: Stores Docker daemon data (images, containers, volumes)
dind-gpu-data: Separate volume for GPU-enabled service

Resource Limits

Default resource limits:

CPU: 2.0 cores (limit), 1.0 core (reservation)
Memory: 4GB (limit), 2GB (reservation)

Adjust these in .env based on your workload.

Advanced Usage

Connect from host

You can connect to the Docker daemon from your host machine:

export DOCKER_HOST=tcp://localhost:2375
docker info

Use in CI/CD

Example GitLab CI configuration:

services:
  - name: your-registry/debian-dind:latest
    alias: docker

variables:
  DOCKER_HOST: tcp://docker:2375

Build Arguments

When building the image manually:

DEBIAN_VERSION: Debian base version (default: 13.2-slim)
INSTALL_NVIDIA_TOOLKIT: Install NVIDIA toolkit (default: false)

Example:

docker build --build-arg DEBIAN_VERSION=13.2-slim --build-arg INSTALL_NVIDIA_TOOLKIT=true -t debian-dind-gpu .

License

This configuration is provided as-is for use with the Compose Anything project.