Docker

Docker — Install and Use Containers

Enables OpenClaw (and Cursor) to install Docker and use it reliably. Base all guidance on official Docker docs; when in doubt, fetch from canonical URLs below.

When to Apply

• User wants to install Docker (macOS, Linux, Windows)
• User asks about containers, images, Dockerfile, docker compose
• Building, running, or debugging Docker commands or workflows
• User asks for "latest Docker docs" or "how do I use Docker"

When running inside Docker Test: The test container already has the Docker CLI and the host socket mounted. Use docker directly to create, run, stop, and remove containers; do not try to install Docker or use sudo. See LEARNINGS.md (Integration with Docker Test).

Canonical Documentation URLs

Rule: For install steps, CLI syntax, or Dockerfile instructions, fetch the relevant doc URL and use that content. Do not rely on training data for version-specific install or command details.

Installation

Install Docker on the host so the docker CLI and daemon are available. After install, ensure the daemon is running (docker run hello-world).

Installation (reliable paths)

macOS

Recommended: Docker Desktop

1. Download from official docs: Install Docker Desktop on Mac.
   • Apple Silicon: https://desktop.docker.com/mac/main/arm64/Docker.dmg
   • Intel: https://desktop.docker.com/mac/main/amd64/Docker.dmg
2. Open Docker.dmg, drag Docker to Applications, then open Docker.app and accept terms.
3. CLI install (optional): After downloading the DMG:

   sudo hdiutil attach Docker.dmg
   sudo /Volumes/Docker/Docker.app/Contents/MacOS/install
   sudo hdiutil detach /Volumes/Docker
   

4. Verify: docker run hello-world

OpenClaw / automation: If docker is missing and the user is on macOS, suggest installing via Homebrew: brew install --cask docker, then starting Docker Desktop so the daemon is running.

Linux (Ubuntu example)

1. Prefer Docker Engine from apt (see Install Docker Engine on Ubuntu).
2. Remove conflicting packages first:

   sudo apt remove $(dpkg --get-selections docker.io docker-compose docker-compose-v2 docker-doc podman-docker containerd runc 2>/dev/null | cut -f1)
   

3. Add Docker’s apt repo, then:

   sudo apt update
   sudo apt install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
   sudo systemctl start docker
   sudo docker run hello-world
   

4. Optional (run without sudo): Linux postinstall — add user to docker group.

Convenience script (dev/test only): curl -fsSL https://get.docker.com -o get-docker.sh && sudo sh get-docker.sh. Not recommended for production.

Windows

Use Get Docker and follow Docker Desktop for Windows (WSL2 backend recommended).

Core Workflow: Build and Run

1. Dockerfile in app directory (see reference.md or Dockerfile reference). If any path in COPY has spaces, quote it (e.g. COPY . "/app/Docker Skill").
2. Build image: docker build -t <name> .
3. Run container: docker run -d -p HOST_PORT:CONTAINER_PORT <name> (e.g. -p 127.0.0.1:3000:3000).
4. List containers: docker ps (running), docker ps -a (all).
5. Stop/remove: docker stop <container>, docker rm <container>.

Example from official getting-started:

docker build -t getting-started .
docker run -d -p 127.0.0.1:3000:3000 getting-started
# Open http://localhost:3000

Usage examples

• Run a one-off command and remove the container:

  docker run --rm alpine echo "Hello from Alpine"
  

• Create, run, then stop and remove a named container:

  docker run --name my-test alpine echo "test"
  docker stop my-test
  docker rm my-test
  

• Pull an image, run a minimal container, then remove container and image:

  docker run --name hello hello-world
  docker rm hello
  docker rmi hello-world
  

• Build and run a web app (port mapping):

  docker build -t myapp .
  docker run -d -p 127.0.0.1:3000:3000 myapp
  docker ps
  docker stop <container_id>
  docker rm <container_id>
  

• Compose (multi-service):

  docker compose up -d
  docker compose logs -f
  docker compose down
  

Daemon Must Be Running

• Docker Desktop (Mac/Windows): Ensure Docker Desktop app is running; docker CLI talks to its daemon.
• Colima (macOS): If using Colima instead of Docker Desktop, set DOCKER_HOST (e.g. unix://$HOME/.colima/default/docker.sock) so the CLI and scripts find the daemon.
• Linux: sudo systemctl start docker (and enable if needed).
• If the user sees "Cannot connect to the Docker daemon", direct them to start Docker Desktop or the engine service and try again.

Quick Reference

• Images: docker pull <image>, docker images, docker rmi <image>
• Containers: docker run, docker ps, docker stop, docker rm, docker logs <container>
• Compose: docker compose up -d, docker compose down — use compose.yaml in project root (see Compose file reference).
• Cleanup: docker system prune -a (removes unused images/containers/networks; use with care).

Volume mounts

When using -v HOST:CONTAINER, use stable host paths (e.g. a directory under the project or skill root). Avoid temporary directories (e.g. from mktemp); they may not mount reliably in some environments (sandboxes, CI, remote Docker). See LEARNINGS.md.

Additional Resources

• For detailed CLI and Dockerfile syntax, see reference.md.
• For full specs, fetch from the official reference and guides.
• For volume-mount and environment learnings, see LEARNINGS.md.