Create and Restore Container Checkpoints with CRIU, buildah, Podman and Docker

CRIU (stands for Checkpoint and Restore in Userspace) is a utility that enables you to set a checkpoint on a running container or an individual application and store its state to disk. You can use data saved to restore the container after a reboot at the same point in time it was checkpointed. It is possible to perform operations like container live migration, snapshots, remote debugging etc.

CRIU is integrated by major container engines such as Docker, Podman, LXC/LXD, OpenVZ, etc for implementing associated functionality. It is also available in respective package repositories for linux distributions.

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Building and managing container images with Buildah

buildah is a open source tool which can be used to build OCI compliant container images without using docker engine. It can also be run in a rootless mode, thereby reducing the attack surface area and also inside a container image itself.

You can use buildah to built container images from existing container images, from Dockerfiles and from scratch (read empty images) as well. OCI images built using buildah are portable and can be run on different hosts as well with different container engines such as CRI-O, Podman, Docker Engine, etc.

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Another blog on docker depreciation in Kubernetes and what needs to be done about it

In the Kubernetes release v1.20, the development team has marked dockershim as deprecated. There was initially some shock and confusion, as it was perceived that team is moving away from docker completely, however that is not the case. As its turns out, what the team is doing, is steering the Kubernetes away from the proprietary parts of Docker or Docker Engine or just simply called Docker. The Docker Engine is further comprised of many different sub-components like dockerd, containerd, runc etc., many of which were initially developed by Docker Inc and then given away to community. These were later standardized and maintained by the community.

The Kubernetes community has written a detailed blog post about deprecation with a dedicated FAQ page for it. This blog post is being written to understand the impact and what needs to be done about it. Depending on how do you use Docker, think and understand about it, you may or may not have to do anything about it or get worried about sleepless nights.

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