====== Working with Openstack ======
  * https://www.mirantis.com/blog/configuring-floating-ip-addresses-networking-openstack-public-private-clouds/


====== Security group ======
  * http://docs.openstack.org/user-guide/content/cli_configure_instances.html

===== Assign Security Group to Instance =====

It is also possible to add and remove security groups when an instance is running. Currently this is only available through the command-line tools. Here is an example:

    $ nova add-secgroup <server> <securitygroup>

    $ nova remove-secgroup <server> <securitygroup>