containerd vs crun

containerd is a free container runtime for managing a host’s container lifecycle. It handles image transfer and storage, execution, and supervision, and is designed to be embedded in a larger system rather than used directly by developers or end users. It supports OCI images and image push and pull operations, and uses runc by default while allowing other OCI-compliant runtimes. Its built-in CRI plugin can make it the container runtime for a Kubernetes cluster, and it supports registries compliant with the OCI Distribution Specification. The daemon is available for Linux and Windows. Network-interface management and image building are outside containerd’s first-class scope, so higher-level systems or tools handle those jobs. Its ctr command-line tool is intended for development and debugging, without a guarantee of a stable interface or a human-friendly experience. Users typically also need runc and CNI plugins. The plan is free; free plan available, with no free trial.

crun is a free, self-hosted OCI container runtime for Linux, written in C. It conforms to the OCI Container Runtime specifications and provides CLI operations for creating, running, executing commands in, listing, pausing, resuming, updating, checkpointing and restoring containers. It can generate a configuration for unprivileged use and creates a user namespace when run by a non-root user. The project documents integration with Podman, an Ansible role for installing a statically linked binary and a Lua binding. Build instructions cover Fedora, RHEL/CentOS Stream 9 and 10, Ubuntu, Alpine and openSUSE Tumbleweed; release binaries are listed for Linux amd64 and arm64, including variants without systemd. Official release artifacts are signed, with GPG verification commands provided. The project reports a benchmark of 100 sequential `/bin/true` containers completing in 1.69 seconds with crun versus 3.34 seconds with runc on the author's machine. The manual marks cgroup v1 support as deprecated. Regular patch releases target the latest version; fixes for earlier versions are best effort and not guaranteed.