ansible-playbook -i ubuntu-16.04LTS/vpn_hosts ubuntu-16.04LTS/vpn.yml
For IKEv2 clients config refer https://gist.github.com/karlvr/34f46e1723a2118bb16190c22dbed1cc#client-setup
To be able to use On demand
switcher on iOS client create profile (use Apple Configurator and refer to example) and add following lines:
<key>OnDemandEnabled</key>
<integer>1</integer>
<key>OnDemandRules</key>
<array>
<dict>
<key>Action</key>
<string>Connect</string>
</dict>
</array>