runc is a CLI tool for spawning and running containers according to the OCP specification. The code can be found at https://github.com/opencontainers/runc.

runC characteristics:

• Embeddable: Containers are started as a child process of runC and there is no daemon that needs managing.
• Battle hardened: runC is built on libcontainer, the same container technology powering millions of Docker Engine installations.
• Compatible with Docker: Docker images can be ran with runC.

Getting started

You can run Docker images pulled with Docker: first you need to run a container for that image, then export it’s file system. You can create a manifest file for runC to run it, or let runC generate one for you.

$ docker export myapp > myapp.tar
$ runc run ./myapp.tar /usr/bin/nginx

Or even just a directory with a filesystem in it:

$ ls myapp
bin      etc      lib      linuxrc  mnt      proc     run      sys      usr
dev      home     lib64    media    opt      root     sbin     tmp      var
$ runc run ./myapp /usr/bin/nginx

Embedding

runc can be embedded into various other systems without having to run a Docker daemon.

Systemd integration

runc does not create a dameon, so it integrates well with systemd.

[Unit]
Description=Minecraft Build Server
Documentation=http://minecraft.net
After=network.target

[Service]
CPUQuota=200%
MemoryLimit=1536M
ExecStart=/usr/local/bin/runc
Restart=on-failure
WorkingDirectory=/containers/minecraftbuild

[Install]
WantedBy=multi-user.target