In order to connect your OnApp account on mist.io, you will need to specify the OnApp host, username and password you use to login on your OnApp account. Alternatively, you can generate an Api key through the profile page on the OnApp dashboard, and specify your email address + Api key on the mist.io add cloud wizard.
Once this info is added correctly, you will be able to see the listing of your OnApp Virtual Servers, with their status, public and private ips, plus metadata.
Depending on the VM state, you may be able to execute any of the following actions: start, stop, reboot, destroy, suspend, resume.
Available actions for a VM that is running.
Along with the above actions, you can use existing mist.io functionality, including tagging, monitoring and alerting, add, import or associate ssh keys and use the web shell, create and run scripts, or schedule tasks and actions for them to run on an automated way.