We have verified that your OpenEDX server was deployed correctly in a few minutes, with no errors, according to our logs.
However, it seems that your browser stopped requesting status updates before the deployment was completed (just after you downloaded the private keys, for some reason). Although the machine was already running the website, the information might have not been properly updated because of that. Then, it seems you reloaded the page and you were able to delete the machine correctly. We have not being able to reproduce this behavior on our side.
Please note that the message that your are mentioning is just a warning. Our images perform the partition resize automatically on first boot.
If you keep finding problems, could you please provide us more info? For example, if you got any errors in your browser. Maybe a screenshot of the error could help, via private message. If possible include timestamps.