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Download Tarball: criu-4.0.tar.gz Version: 4.0 "CRIUDA" Released: 20 Sep 2024 GIT tag: v4.0 Installation • Usage Releases

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

Checkpoint/Restore In Userspace, or CRIU (pronounced kree-oo, IPA: /krɪʊ/, Russian: криу), is a Linux software. It can freeze a running container (or an individual application) and checkpoint its state to disk. The data saved can be used to restore the application and run it exactly as it was during the time of the freeze. Using this functionality, application or container live migration, snapshots, remote debugging, and many other things are now possible.

CRIU started as a project of Virtuozzo, and grew with the tremendous help from the community. It is currently used by (integrated into) OpenVZ, LXC/LXD, Docker, Podman, and other software, and packaged for many Linux distributions.

Events LinuxDays 2024 13 Oct 2024, On the Edge of Tomorrow: Checkpoint/Restore in Containers Kubernetes Community Days Austria 09 Oct 2024, Forensic container checkpointing and analysis Linux Plumbers Conference 2024 18-20 Sep 2024, Containers and Checkpoint/Restore Microconference Other talks: * Userspace memory persistence over kexec * Checkpoint/Restore In eBPF (CRIB)

Using

Getting packages for your distribution

Or try manual installation to have CRIU on your system

CLI, RPC and C API

Three ways to start using the C/R functionality. More info about APIs.

Usage scenarios

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

Category:HOWTO

Collection of real world examples of how to use CRIU. Some are complex, some are not. HOW TO dump a simple loop might be the best one to start with. Also a set of asciinema records for real-life examples.

FAQ & When C/R fails

A sort of troubleshooting guide

What can change after C/R

CRIU cannot (yet) save and restore every single bit of tasks' state. This page describes what bits visible through standard kernel API are such.

What cannot be checkpointed

What an application could do to make CRIU refuse to dump it.

Contacts

Ways to communicate with CRIU community

Developing

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

Images

Description of image files format

Plugins

CRIU can call plugins provided by people

Upstream kernel commits

Mainline kernel commits tracker

Recent commits

CRIU tool repository commits

Manpages

Kernel's manpages commits tracker

ZDTM Test Suite

Zero downtime test suite

TODO

Current TODO list

User namespace

Implementing user namespace support

Postulates

What to keep in mind when writing new code

Code coverage results

Shows how zdtm run covers the criu code paths

How to submit patches

Under the hood

• Checkpoint/Restore
• Category:Under the hood
• Category:Network
• Category:Files
• Category:Memory
• Pending signals
• Stages of restoring
• Code blobs
• Comparison to other CR projects

External links

• 2024-09-06, Live Migration of Multi-Container Kubernetes Pods in Multi-Cluster Serverless Edge Systems
• 2024-09-04, Towards Efficient End-to-End Encryption for Container Checkpointing Systems
• 2024-08-04, Custom Page Fault Handling With eBPF
• 2024-08-03, Software-based Live Migration for Containerized RDMA
• 2024-07-30, Packet Buffering to Minimize Service Downtime and Packet Loss During Redundancy Switchover
• 2024-07-30, Don't, Stop, Drop, Pause: Forensics of CONtainer CheckPOINTs (ConPoint)
• 2024-07-25, MDB-KCP: persistence framework of in-memory database with CRIU-based container checkpoint in Kubernetes
• 2024-07-23, Dapper: A Lightweight and Extensible Framework for Live Program State Rewriting
• 2024-07-07, FastMig: Leveraging FastFreeze to Establish Robust Service Liquidity in Cloud 2.0

More external articles...

Misc

• Academic Research
• Podcasts and other audio/video interviews
• Project history
• Logo description
• Events
• CRIU acronym fun