Use dbus to register a container as a machine so it shows up in machine ctl

regmachine.go

package main

import (
	"encoding/hex"
	"flag"
	"log"

	"github.com/godbus/dbus"
)

var conn *dbus.Conn

// RegisterMachine with systemd on the host system
func RegisterMachine(name string, id string, pid int, root_directory string) error {
	var (
		av  []byte
		err error
	)

	if conn == nil {
		conn, err = dbus.SystemBus()
		if err != nil {
			return (err)
		}
	}

	av, err = hex.DecodeString(id[0:32])
	if err != nil {
		return err
	}

	obj := conn.Object("org.freedesktop.machine1", "/org/freedesktop/machine1")
	return obj.Call("org.freedesktop.machine1.Manager.RegisterMachine", 0, name, av, "docker.service", "container", uint32(pid), root_directory).Err
}

func main() {
	pid := flag.Int("pid", -1, "pid of the machine")
	rootDir := flag.String("root", "", "root directory of the machine")
	name := flag.String("name", "", "name of the machine")
	id := flag.String("id", "", "id of the machine")
	flag.Parse()

	if *pid == -1 {
		log.Fatalf("PID should be specified")
	}
	if *rootDir == "" || *name == "" || *id == "" {
		log.Fatalf("invalid argument")
	}
	if err := RegisterMachine(*name, *id, *pid, *rootDir); err != nil {
		log.Fatalf("Register machine failed: %v", err)
	}
}