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crun

containeroci-runtimeopen source

A fast, low-memory OCI runtime written in C, the default executor under Podman.

crun is a drop-in OCI runtime from the containers project, fully written in C, that does the same job as runc, turning an OCI bundle into a running container out of namespaces, cgroups, and seccomp, while starting faster and using significantly less memory. It is the default runtime under Podman and on Fedora/RHEL, can be used by Docker and containerd, and is also usable as a library.

Strengths

  • Faster startup and much lower memory footprint than runc
  • Default OCI runtime under Podman
  • Embeddable, usable as a C library

Limitations

  • Shared kernel, a plain container is not a hard security boundary
  • No images, networks, or lifecycle, that is the engine's job
  • Linux only

Sources