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Download Tarball: criu-4.2.1.tar.gz Version: 4.2.1 "CRIUTIBILITY" Released: 21 Jul 2026 GIT tag: v4.2.1 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.

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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 DFRWS USA 2026 27-30 July, 2026, Arlington, Virginia, USA Forensic Analysis of Container Snapshot Chains for Post-Event Reconstruction EuroMLSys 2026 27 April, 2026, Edinburgh, United Kingdom Towards On-the-Fly Snapshot Memory Compression for Low-Latency Elastic Inference Serving Systems KubeCon EU 2026 24-26 March, 2026, Amsterdam, Netherlands Ctrl-X, Ctrl-V Your Pods: WG Checkpoint Restore in Kubernetes Optimizing Error Recovery for Cost-Efficient Distributed AI Model Training with Kubernetes

Under the hood

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

External links

• 2026-07-22, Forensic Analysis of Container Snapshot Chains for Post-event Reconstruction
• 2026-07-14, Accelerating Model Inference with On‑the‑Fly Snapshot Compression
• 2026-07-09, Reverse-engineering NVIDIA's cuda-checkpoint for Faster Cold Starts
• 2026-06-29, Fast vLLM: cutting cold starts by 20x
• 2026-06-25, Elastic Resource Management for Heterogenous Container-Based Clouds
• 2026-06-01, NVIDIA Dynamo Snapshot: Fast Startup for Inference Workloads on Kubernetes
• 2026-05-12, How we achieved truly serverless GPUs
• 2026-04-27, Towards On-the-Fly Snapshot Memory Compression for Low-Latency Elastic Inference Serving Systems
• 2026-04-06, Cloudburst: 70x faster cold(ish) starts for SGLang
• 2026-02-24, GPU Checkpoint/Restore Made Fast and Lightweight
• 2026-01-21, Announcing the Checkpoint/Restore Working Group
• 2025-11-17, Engine-Agnostic Model Hot-Swapping for Cost-Effective LLM Inference

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