Podman is a production-grade, daemonless container engine that provides a CLI, a REST API (both Docker-compatible and libpod-specific), and a remote client. The codebase is organized around a dual-runtime architecture (local ABI and remote tunnel) that shares entity types and domain interfaces. It supports full container lifecycle management, pod management, image building (via Buildah), volume and secret management, Kubernetes YAML generation and application (play kube), and virtual machine management for macOS, Windows, and Linux via multiple providers (QEMU, AppleHV, Hyper-V, WSL, libkrun). Systemd integration is deep, including Quadlet for generating systemd unit files from container definitions. The codebase is cross-platform (Linux, FreeBSD, macOS, Windows) with extensive build tags and platform-specific implementations. It includes a comprehensive test suite covering unit, integration, end-to-end (Ginkgo), Python API, and system (BATS) tests. The architecture is modular, with clear separation between CLI, API handlers, bindings, domain logic, and platform abstractions.
The Moby project is the upstream open-source project for Docker Engine, implementing a container platform with daemon/client architecture. It provides container lifecycle management, image handling, networking, storage, and orchestration capabilities through a highly modular design with swappable components for storage drivers, network drivers, logging drivers, and authorization plugins. The codebase demonstrates strong engineering practices including context propagation, consistent error handling, plugin architecture, and functional options patterns. The system uses containerd as the underlying container runtime and exposes both HTTP and gRPC APIs for client interaction.