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.

CRIU is a sub-project of OpenVZ Linux Containers.

Latest version

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

Bugfixes

Full changelog.

Old versions

4.x

The following 4.x releases were made:

• 4.2 "CRIUTIBILITY"
• 4.1.1 "CRISCV"
• 4.1 "CRISCV"
• 4.0 "CRIUDA"

3.x

The following 3.x releases were made:

• 3.19 "Bronze Peacock"
• 3.18 "Silver Sandpiper"
• 3.17.1 "Radiant Redstart"
• 3.17 "Radiant Redstart"
• 3.16.1 "Petrified Puffin"
• 3.16 "Petrified Puffin"
• 3.15 "Titanium Falcon"
• 3.14 "Platinum Peacock"
• 3.13 "Silicon Willet"
• 3.12 "Ice Penguin"
• 3.11 "Glass Flamingo"
• 3.10 "Granite Eagle"
• 3.9 "Sand Martin"
• 3.8.1 "Snow Bunting"
• 3.8 "Snow Bunting"
• 3.7 "Vinyl Magpie"
• 3.6 "Alabaster Finch"
• 3.5 "Clay Jay"
• 3.4 "Cobalt Swan"
• 3.3 "Crystal Pelican"
• 3.2.1
• 3.2 "Tin Hoopoe"
• 3.1 "Graphene Swift"
• 3.0 "Basalt Wagtail"

2.x

The following 2.x releases were made:

• 2.12.1
• 2.12 "Vulcanite Rook"
• 2.11.1
• 2.11 "Acrylic Bullfinch"
• 2.10 "Brass Waxwing"
• 2.9 "Silk Tit"
• 2.8 "Bronze Siskin"
• 2.7 "Rubber Owl"
• 2.6 "Paper Crane"
• 2.5 "Concrete Oriole"
• 2.4 "Marble Lark"
• 2.3 "Wooden Duck"
• 2.2 "Carbon Nightingale"
• 2.1 "Steel Lapwing"
• 2.0

1.x

The following 1.x releases were made:

• 1.8
• 1.7.2
• 1.7
• 1.6.1
• 1.6
• 1.5.2
• 1.5.1
• 1.5
• 1.4
• 1.3.1
• 1.3
• 1.3-rc2
• 1.3-rc1
• 1.2
• 1.1
• 1.1-rc2
• 1.1-rc1
• 1.0

0.x

The following 0.x releases were made:

• 0.8
• 0.7
• 0.6
• 0.5
• 0.4
• 0.3
• 0.2
• 0.1

See also

• Changelogs to see all the changelogs on a single page.

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, 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

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...