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Download Tarball: criu-4.2.tar.gz Version: 4.2 "CRIUTIBILITY" Released: 13 Nov 2025 GIT tag: v4.2 Installation • Usage Releases

Welcome to CRIU, a project to implement checkpoint/restore functionality for Linux in userspace.

Checkpoint/Restore In Userspace, or CRIU, is a software tool for Linux operating system. Using this tool, you can freeze a running application (or part of it) and checkpoint it to a hard drive as a collection of files. You can then use the files to restore and run the application from the point it was frozen at. The distinctive feature of the CRIU project is that it is mainly implemented in user space.

The project is currently under very active development. CRIU is a sub-project of OpenVZ.

Using

CR tools

Main checkpoint/restore utility description (sort of HOWTO)

Usage scenarios

Ideas how crtools can be used (some are crazy indeed)

What software is supported

Describes TODO list in higher level terms

LXC

How to dump and restore an LXC container

Developing

If you're interested in CRIU development, please subscribe to the criu mailing list: https://openvz.org/mailman/listinfo/criu

Images

Description of image files format

Commits

Mainline kernel commits tracker

ZDTM Test Suite

Zero downtime test suite

TODO

Current TODO list

Events Linux Plumbers Conference 2025 December 12, 2025, Tokyo, Japan, Containers and Checkpoint/Restore Microconference Files on Unmounted Mounts Guarded Control Stack on arm64: Challenges in Enabling Shadow Stack Support for CRIU Optimizing Checkpoints with Built-in Memory Page Compression CANOPIE-HPC @ Supercomputing 2025 November 17, 2025, St. Louis, MO Engine-Agnostic Model Hot-Swapping for Cost-Effective LLM Inference Container Plumbing Days 2025 August 28, 2025, Amsterdam, Netherlands Enabling Secure Container Checkpointing for Distributed Model Training High Performance Container Workshop @ ISC 2025 June 13, 2025, Hamburg, Germany Transparent Hot-Swapping of Containerized AI/ML Workloads

Under the hood

• Sockets
• Memory dumping and restoring
• Checkpoint/Restore
• TCP connection
• Porting crtools to new kernel releases
• Files

External links

• 2025-11-17, Engine-Agnostic Model Hot-Swapping for Cost-Effective LLM Inference
• 2025-08-13, Software Availability Protection in Cyber-Physical Systems
• 2025-07-14, PhoenixOS: Concurrent OS-level GPU Checkpoint and Restore with Validated Speculation
• 2025-06-18, Improving Checkpoint/Restore Functionality in Kubernetes
• 2025-06-17, LWN.net: A parallel path for GPU restore in CRIU
• 2025-06-13, Kubernetes Scheduling with Checkpoint/Restore: Challenges and Open Problems

More external articles...

Other

• Project history
• Logo description
• Events
• Join the CRIU acronym fun

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CRIU is a sub-project of
http://static.openvz.org/wiki/openvz-logo.png