How to use crun with docker?

[mviereck]

I would like to try crun as docker runtime. How can I set it up to use it with docker run option --runtime=crun?

I currently tried kata with --runtime=kata-runtime and find it quite interesting. It would be nice to try crun, too.

[giuseppe]

are you using a config file (--config-file) for configuring Docker?

I've configured it passing --add-runtime on the dockerd command line. To do so I modified the systemd service file adding --runtime=crun=/usr/local/bin/crun.

After that, you can either configure crun as the default runtime for Docker via --default-runtime=crun or you can specify it for each container with docker run ... --runtime=crun ...

[mviereck]

I did not thought it could be that easy, thank you!

I have configured /etc/docker/daemon.json, providing runc, kata-runtime and now also crun:

$ cat /etc/docker/daemon.json 
{
  "default-runtime": "runc",
  "runtimes": {
    "kata-runtime": {
      "path": "/opt/kata/bin/kata-runtime",
      "runtimeArgs": [
              "--kata-config /etc/kata/configuration.toml"
      ]
    },
    "crun": {
      "path": "/usr/local/bin/crun"
    }
  }
}

I just had a successfull first test run with --runtime=crun.