Returns the value of a cgroup parameter for a container

    path
        path to the container parent directory
        default: /var/lib/lxc (system)

        .. versionadded:: 2015.8.0

    CLI Example:

    .. code-block:: bash

        salt '*' lxc.get_parameter container_name memory.limit_in_bytes

def get_parameter(name, parameter, path=None):
    '''
    Returns the value of a cgroup parameter for a container

    path
        path to the container parent directory
        default: /var/lib/lxc (system)

        .. versionadded:: 2015.8.0

    CLI Example:

    .. code-block:: bash

        salt '*' lxc.get_parameter container_name memory.limit_in_bytes
    '''
    _ensure_exists(name, path=path)
    cmd = 'lxc-cgroup'
    if path:
        cmd += ' -P {0}'.format(pipes.quote(path))
    cmd += ' -n {0} {1}'.format(name, parameter)
    ret = __salt__['cmd.run_all'](cmd, python_shell=False)
    if ret['retcode'] != 0:
        raise CommandExecutionError(
            'Unable to retrieve value for \'{0}\''.format(parameter)
        )
    return ret['stdout'].strip()