from fabfile import task, env, run, execute, settings

@task
def my_command():
    host, arg = env.host_string.split('_')
    with settings(host_string=host):
        run("python do_command.py {}".format(arg))

@task
def do_commands():
    hosts = ['10.0.0.2', '10.0.0.3', '10.0.0.4', '10.0.0.5']
    command_args = []
    for host in hosts:
        for arg in range(9):
            command_hosts.append("{}_{}".format(host, arg))
    with settings(parallel=True):
        execute(my_command, hosts=command_hosts)
****
fab do_commands