environment variables

Hello

I am trying to use environment variables in my playbook instead of static entries.
For example username, password etc. for Openstack.

I have seen this page
http://docs.ansible.com/playbooks_environment.html
But I don’t understand how to pass specific environment variables inside a playbook.

In case of Openstack we have
OS_PASSWORD=Password1
OS_AUTH_URL=http://controller:35357/v2.0
OS_USERNAME=demo
OS_TENANT_NAME=demo

How can I assign these in a playbook such as this
http://pastebin.com/aMaihCme

Thanks!

i think what you want is:
lookup('env', 'OS_PASSWORD')

Thanks Brian.