# Docker-Specific Guide

## Docker vs Podman

This project prioritizes **Podman** (OCI-compliant, rootless, daemonless). For Docker, convert commands:

```bash
# Podman → Docker
podman build -t name .    →  docker build -t name .
podman run -d name        →  docker run -d name
```

## Key Differences

### SELinux

**Podman**: Native support, use `:Z` or `:z` for volumes

```bash
podman run -v ./data:/data:Z name
```

**Docker**: Requires `selinux` mount option

```bash
docker run -v ./data:/data:Z name  # May not work
docker run --security-opt label=type:container_t name
```

### Rootless

**Podman**: Default rootless operation

```bash
podman run -d -p 8080:8080 name  # Works as user
```

**Docker**: Requires rootless daemon setup

```bash
dockerd-rootless-setuptool.sh install
```

### Systemd

**Podman**: Native integration

```bash
podman generate systemd --new name
```

**Docker**: Use third-party solutions

## Docker Files

Use `Dockerfile` instead of `Containerfile`:

```bash
docker build -f assets/Dockerfile.alpine -t argparse-builder .
```

## Docker Compose

Standard `docker-compose.yml` works, but note SELinux limitations:

```yaml
services:
  app:
    volumes:
      - ./data:/data # No :Z support in Docker Compose
```

Workaround:

```bash
chcon -Rt container_file_t ./data  # Pre-label directory
```

## Migration to Podman

1. Replace `docker` with `podman` in commands
2. Add `:Z` to volume mounts for SELinux
3. Use rootless by default
4. Generate systemd units with Podman

See `docs/container.md` for full Podman guide.