What is Checkpoint/Restore In Userspace?

Checkpoint/Restore In Userspace (CRIU) is a tool that allows the checkpointing and restoration of Linux processes. It allows the user to save the state of a running application, including open files, network connections, and process memory. This saved state can then be used to restart the application at the same point it was checkpointed, potentially on a different system or with different resources available.

CRIU is often used in container environments, where it enables live migration of containers between hosts without downtime. It can also be used for process migration, incremental backups, debugging, and testing. CRIU is an open-source project that is actively maintained by the Linux community.