Open-source alternatives to Crun

Youki is an OCI container runtime written in Rust. It implements the Open Container Initiative runtime specification to manage the lifecycle of containerized processes and ensure compatibility with standard container images and engines. The runtime is designed for memory safety and supports rootless container execution, allowing containers to run as non-root users to reduce security risks and limit privilege escalation. It provides core container management capabilities, including spawning and managing OCI containers. This is achieved through Linux namespace isolation, cgroup-based resource

Incus is a unified orchestration platform for managing system containers, OCI application containers, and virtual machines through a single control plane. It brings together cluster infrastructure management, secure multi-tenancy, software-defined networking, and pluggable storage backend orchestration into one cohesive system exposed via a full REST API and command-line interface. What distinguishes Incus is its ability to run multiple instance types side by side—full Linux system containers, OCI application containers, and QEMU virtual machines—all managed with consistent tooling. Networkin

Docker CE is an OCI compliant container platform and runtime engine used for building and running applications within isolated environments. It functions as a Linux container orchestrator and provides a command-line interface to manage the entire lifecycle of running application instances. The platform enables containerized application deployment and cross-platform software distribution by packaging software with its dependencies. It supports microservices architecture management and the creation of reproducible local development environments. The system includes capabilities for application

Docker is an OCI container engine and runtime orchestrator used to build, run, and manage isolated applications. It functions as a container image builder for creating portable snapshots of applications and a registry manager for storing, versioning, and distributing those images across environments. The platform provides a centralized daemon to control the creation, execution, and termination of containerized workloads. It allows for the assembly of modular container systems by combining build tools, registries, and runtimes. Its core capabilities cover container image creation, registry ad

Moby is an OCI container engine and runtime manager designed for building, running, and managing isolated containers based on Open Container Initiative standards. It functions as a container daemon and image builder, providing a core engine to orchestrate the full lifecycle of containers and the packaging of source code into portable images. The project provides a standardized HTTP interface that allows for programmatic container management, enabling external clients to control daemon settings and container operations. It supports a rootless security model, allowing the engine daemon to execu

LXC is an OS-level virtualization framework and Linux container manager used to run multiple isolated Linux systems on a single host. It functions as a kernel namespace orchestrator and unprivileged container runtime, allowing for the creation and management of system containers without the overhead of a hypervisor. The project provides unprivileged container execution by mapping container root users to unprivileged host users to prevent host system access. It ensures security through system call filtering and root user isolation, enabling containers to run without requiring host root privile

CRIU is a Linux process checkpointing tool and state manager used to freeze running applications and save their memory and state to disk for later restoration. It functions as a container migration engine and an OCI checkpoint image converter, allowing the live state of running containers to be transferred between different hosts. The project distinguishes itself through its ability to persist network connectivity, acting as a TCP connection state persister that saves and reconstructs network socket states to maintain active communication after a restart. It further enables the distribution o

CRI-O is an open-source container runtime that implements the Kubernetes Container Runtime Interface (CRI) to manage container images, pods, and containers on cluster nodes using OCI-compatible runtimes. It serves as a node-level container manager that handles image pulling, container lifecycle, and resource monitoring for Kubernetes clusters, running containers according to the Open Container Initiative specifications. The runtime distinguishes itself through live configuration reloading that applies changes to runtime definitions, registry mirrors, and TLS certificates without restarting th

This project is a Docker educational resource and a collection of practical examples designed for learning containerization technologies. It serves as a guide for understanding container fundamentals, including the creation and management of custom images and the use of registries. The repository provides specialized references for container security hardening, such as managing kernel privileges and implementing supply chain security. It also includes tutorials for multi-container orchestration and a DevOps guide focused on CI/CD automation and image optimization. The material covers a broad

Isolate is a low-level sandbox designed to execute untrusted programs within a strictly controlled environment. It functions as a process isolation engine that prevents potentially harmful code from interacting with or damaging the host operating system. The tool leverages Linux kernel primitives, including namespaces and control groups, to partition system resources and enforce hardware usage boundaries. By applying filesystem virtualization and system call filtering, it restricts the visibility and interaction of a process with the host, ensuring that untrusted applications operate only wit

Dify-sandbox is a secure runtime environment designed for the execution of untrusted code snippets. It functions as a containerized sandbox that isolates processes from the host operating system, ensuring that arbitrary scripts can be run without granting them unauthorized access to sensitive data or critical system resources. The project distinguishes itself through a multi-layered security approach that combines kernel-level isolation with strict resource management. By utilizing Linux namespaces and container-based process isolation, it partitions system resources to maintain visibility bo

Pouch is a Linux container runtime and OCI container engine designed to execute containerized applications. It functions as a Kubernetes container runtime, integrating with orchestrators to manage the lifecycle of pods and isolated application environments. The project features a peer-to-peer image distribution system to deliver large container images across large-scale clusters while reducing bandwidth load. It also provides support for legacy Linux kernel versions, allowing modern container runtimes to maintain compatibility with older hardware. The runtime implements application isolation

rkt is a secure Linux container engine and pod-native container manager. It provides a composable execution environment for launching and managing isolated application containers on Linux, serving as a runtime designed around open industry standards for image formats and networking interfaces. The system is distinguished by a pod-native execution model that groups multiple containers and shared resources into single, self-contained units. It utilizes pluggable execution engines to provide secure isolation, including the use of hardware-based virtualization to create security boundaries betwee

Libpod is a container management library for running and controlling the lifecycle of Open Container Initiative compliant containers and images across different storage backends. It provides a programmatic interface for the remote control and automation of container environments. The project enables the coordination of multiple containers into pods that share network namespaces and other shared resources. It supports rootless container execution by using user namespaces to launch containers without administrative privileges. The library covers a broad range of system operations, including im

Firejail is a Linux application sandbox and kernel security wrapper that isolates untrusted applications from the host system. It uses kernel namespaces and seccomp filters to restrict filesystem access, drop kernel capabilities, and limit the system attack surface. The project is distinguished by its use of predefined security profiles to automatically apply filesystem restrictions and syscall limits based on the executable being launched. It provides specialized isolation for portable packages such as AppImages and implements X11 display isolation via proxy servers to prevent keyboard loggi

Dockerode is a Node.js library that provides programmatic management of Docker containers, images, and volumes by acting as a wrapper for the Docker Remote API. It enables JavaScript applications to interact with a Docker engine via Unix sockets or TCP network interfaces. The project covers container lifecycle management, including launching instances and executing commands with bidirectional input and output streaming. It also provides capabilities for building container images, pulling images from registries, and configuring virtual networks. Additional functionality includes the coordinat

Bubblewrap is a Linux sandbox runner that creates lightweight, isolated execution environments for running untrusted applications. It combines Linux user, mount, network, PID, and UTS namespaces with seccomp-BPF system call filtering to restrict filesystem, network, process, and inter-process communication access. The project provides comprehensive process isolation by giving each sandbox its own private tmpfs root with selective bind-mounts, a separate network stack containing only a loopback interface, an independent process ID space, and remapped user and group identifiers. It applies secc

This project is a comprehensive reference guide and cheat sheet for the Docker CLI. It provides a structured collection of commands and documentation to help users manage container lifecycles, build images, and handle registries. The documentation specifically covers the orchestration of multi-container applications using Docker Compose and the management of scalable services across multiple nodes via Docker Swarm. It also includes detailed guides for configuring virtual networks, bridges, and ports to control container communication. The reference surface extends to container image administ

Unikraft is a modular library operating system and unikernel framework designed to compile applications into minimal, bootable virtual machine images. It serves as an OCI-compliant image builder and a cloud-native hypervisor target, enabling the creation of specialized runtimes that include only the specific drivers and libraries required by a single application. The system features a Linux compatibility layer that maps standard API calls and POSIX standards to unikernel libraries, allowing unmodified binaries to run without a full general-purpose kernel. It distinguishes itself by allowing c

OSV is a unikernel operating system and cloud-native execution environment designed to run as a secure microVM on hypervisors such as KVM, Firecracker, Xen, and VMware. It functions as a Linux binary compatible runtime, allowing unmodified Linux binaries to be executed as secure microVMs without requiring recompilation. The project distinguishes itself through its ability to package applications into minimal bootable images and its provide of a virtual machine management API. This REST interface enables remote monitoring of system health, management of execution traces, and control over guest

This project is a collection of curated and standardized Docker base images that serve as reliable starting points for building containerized applications. It functions as an OCI container image repository and a build template library, providing a central source of truth for images that adhere to Open Container Initiative standards for portability. The project utilizes an automated image lifecycle pipeline to build, tag, and push images, ensuring that dependencies remain current and security patches are applied. It specifically supports cross-platform distribution by providing a multi-archite

LXD is a unified platform for managing both system containers and virtual machines through a single REST API and command-line interface. It provides a programmatic HTTP interface for controlling the full lifecycle of instances, enabling automation and integration with external tools. The system runs unprivileged containers with per-instance UID/GID mappings, seccomp filters, and AppArmor profiles for kernel-level isolation, while supporting multiple storage backends including directory, Btrfs, LVM, ZFS, Ceph, LINSTOR, and TrueNAS through a unified driver interface. The platform distinguishes

Bubblewrap is an unprivileged sandbox execution utility for Linux that isolates processes from the host system. It creates secure environments by leveraging Linux namespaces to separate system resources, including network, PID, and IPC stacks. The project distinguishes itself by enabling the execution of untrusted software without requiring root privileges on the host machine. It prevents privilege escalation by disabling the execution of setuid binaries and uses user identity mapping to isolate process permissions from the host operating system. The tool manages a comprehensive security sur

dockerlabs is a collection of educational labs and technical tutorials designed to teach the fundamentals of containerization and microservice architecture. It provides instructional material and hands-on exercises covering image optimization, security training, infrastructure setup, and cluster orchestration. The project features specific courses and guides focused on reducing image size through multi-stage builds, securing workloads via vulnerability scanning and encrypted networks, and deploying multi-node clusters with high availability using Swarm orchestration. The materials cover a br

Sol2 is a C++ Lua binding library that serves as a language interoperability layer for integrating Lua scripts into C++ applications. It acts as a scripting wrapper and API toolkit, enabling the execution of Lua code and the management of shared state within a native C++ environment. The library focuses on automated function and type mapping to bridge native C++ classes and complex data types with the Lua scripting engine. It provides mechanisms for bidirectional data exchange, allowing compiled logic and variables to be synchronized between the host application and the script runtime. The s

rkt is a pod-native container engine and runtime for Linux that executes containerized applications as isolated pods. It serves as an OCI container runtime and a Linux container manager, supporting the execution of images based on Open Container Initiative, appc, and Docker specifications. The project distinguishes itself by offering hardware-level container isolation, allowing pods to run within virtual machines using KVM or QEMU for a dedicated kernel. It further separates itself through secure container deployment practices, utilizing SELinux mandatory access control and TPM-backed integri

This project provides a suite of diagnostic and validation utilities for container runtimes that implement the Kubernetes Container Runtime Interface. It serves as a command-line interface for interacting with and managing container lifecycles, images, and sandboxes directly on a host machine without requiring a full cluster deployment. The toolset distinguishes itself through its focus on interface compliance and performance verification. It includes automated test suites that validate whether a runtime adheres to defined interface specifications and handles resource plugin integration corre