These are my notes on making OpenStack play well with firewalld and NetworkManager.

NetworkManager

By default, NetworkManager attempts to start a DHCP client on every new available interface. Since booting a single instance in OpenStack can result in the creation of several virtual interfaces, this results in a lot of:

May 19 11:58:24 pk115wp-lkellogg NetworkManager[1357]: <info>
  Activation (qvb512640bd-ee) starting connection 'Wired connection 2'

You can disable this behavior by adding the following to /etc/NetworkManager/NetworkManager.conf: