reexec is something like clone.

reexec.go

args := []string{"fork"}
...

cmd := reexec.Command(args...)
cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
cmd.SysProcAttr = &syscall.SysProcAttr{
	Cloneflags: syscall.CLONE_NEWUTS |
		syscall.CLONE_NEWIPC |
		syscall.CLONE_NEWPID |
		syscall.CLONE_NEWNS,
}