cloud-config for crun+docker on flatcar

cloud-config.yaml

#cloud-config

coreos:
  units:
    - name: docker.service
      command: start
      drop-ins:
        - name: 50-crun-runtime.conf
          content: |
            [Service]
            Environment=DOCKER_OPTS='--add-runtime crun=/opt/bin/crun --default-runtime=crun'
    - name: crun-fetch.service
      command: start
      content: |
        [Unit]
        Description=fetch crun binary
        Before=docker.service

        [Service]
        Type=oneshot
        ExecStart=/usr/bin/mkdir -p /opt/bin
        ExecStart=/usr/bin/curl -sSL -o /opt/bin/crun https://github.com/containers/crun/releases/download/0.14.1/crun-0.14.1-static-x86_64
        ExecStart=/usr/bin/chmod +x /opt/bin/crun