devstack: No module named oslo_concurrency 解决方法

    在通过devstack搭建openstack环境，并配置了ceilometer服务的情况下，执行stack.sh，会报如下错误：

"/opt/stack/ceilometer/ceilometer/utils.py", line 33, in <module>
2014-12-04 06:20:15.086 | from oslo_concurrency import processutils
2014-12-04 06:20:15.086 | ImportError: No module named oslo_concurrency

解决方法：

sudo apt-get install python-pip python-dev -y
sudo pip install oslo.concurrency --upgrade