Colima vs crun

Colima runs container environments on macOS and Linux, with Docker, containerd, Kubernetes and Incus runtime options. Docker compatibility is intended to let existing Docker workflows and tools continue without changes; containerd users can use nerdctl for a Docker-like command line. It can launch a local, single-node k3s cluster, and users can select an exact K3s version. CPU, memory and disk allocations are configurable, and multiple isolated instances can run with different settings. Colima also documents GPU-accelerated AI workloads on Apple Silicon using Krunkit, with model runners supporting Docker AI Registry and HuggingFace; Ramalama also supports Ollama registries. Those workloads require Apple Silicon, macOS 13 or newer, and Krunkit, with at least 8 GB of RAM recommended. The AI containers are isolated from the host filesystem, other containers and network access unless network access is enabled. Colima is free and MIT-licensed, with installation options for macOS and Linux. Incus virtual machines require m3 or newer Apple Silicon.

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.