DevConf.cz 2021

One of the main reasons Checkpoint/Restore in User-Space (CRIU) exists is to enabled container live migration and although container live migration is always viewed as an outlier or corner case of containers, because containers are supposed to be stateless, CRIU continues to get better at container live migration. Maybe containers are supposed to be stateless, but CRIU still sees growing interest in its container migration features and especially the integration in container runtimes. In this talk I want to present details about CRIU and with which clever tricks it provides the ability to checkpoint and restore processes and whole containers. I also want to show how it is integrated in container runtimes like runc, crun, lxc/lxd, borg and Podman. I want to close the talk with a few demos showcasing CRIU's features in Podman as presented before to live migrate containers and how to use checkpoints to decrease the container startup time. The goal of this talk is to give a technical presentation how containers can be live migrated, that it is easily possible to live migrate containers and that the container migration technology has additional use cases.