Using a Docker image will require that you already have access to an Openstack. The ubuntu-openstacks scripts run only on native Ubuntu with virtualization available.
Copy your .rc file with the openstack credentials in fortistacks folder.
From fortistacks folder:
docker run -v $PWD:/fortistacks/ -v $HOME/.ssh:/root/.ssh/ --rm -i --name fortistacks-cli -h fortistacks-cli -t thomnico/fortinet-cse:fortistacks-cli-1.2
Or adapt to your folder layout.
Once started cd /fortistacks/ and simply source your RC-file than you get from https://citycontrolpanel.com/openstack#openstack_api_access (link in the parameters of the user) Be sure to add:
export OS_FLAVOR=1C-1GB
export EXT_NET=ext-net
At the end of your RC-file first.
Check Dockerfile in this folder to see how it is done. Have to use pinpoint version due to weeks long bugs in openstack clients.
$ docker run -v $PWD:/fortistacks/ -v $HOME/.ssh:/root/.ssh/ --rm -i --name fortistacks-cli -h fortistacks-cli -t fortistacks-cli:1.2