How to find out which version of OpenStack is installed?

I frequently hear the following questions:
"Which OpenStack version is installed?" and "I am not able to determine the name of Openstack release running on my machine?"

So here is a quick way to find out:

1. SSH to your openstack hosts.
2. Run 

openstack --version

OpenStack Client Release Names:

• Ocata 3.8.1
• Newton 3.2.0
• Mitaka 2.3.0
• Liberty 1.7.3
• Kilo 1.0.6
• Juno 0.4.1
• Icehouse 0.3.1

same way for other specific services  too, for example:

nova-manage --version
cinder-manage --version
glance-manage --version

Click here to find further details about Openstack versions