I'm new to Amazon EC2. I've launched my first instance, and am using it as a web server. I see that it has a public DNS (a public URL), e.g.:

ec2-123-45-6-789.compute-1.amazonaws.com

I can successfully go to this server in my browser, hit it via cURL, etc.

I want to use this web server for a back-end service in an app I'm building, so I placed this URL in my app's config, and it works great.

But when I manually stop and re-started my instance, I see that the public DNS changes! I've read that this happens when you explicitly stop and re-start, but doesn't happen if you just "reboot".

I don't plan on explicitly stopping and re-starting this server ever, but my question is: will this public DNS ever change on its own for any reason? E.g. if the machine abnormally crashes, or whatever.

In other words, is it safe to ship an app that's wired to this URL?

Thanks!