Is it safe to run do-release-upgrade on a cloud VM?

Solution 1:

Yes

I just did this to about 110 EC2 instances. I actually did it from Ubuntu 14.04 through 16.04 and up to 18.04 using an automated the process for that many instances. It turns out it is possible to automate do-release-upgrade

If you want to be really safe, take a snapshot of the root disk before going forward.

Make a clone of your instance or spin up a test instance and do the upgrade. There are a lot of changes in Ubuntu from 14.04 to 18.04, a lot. A number of things broke, and SystemD changes a lot of default behavior.

But there are quite a bit fewer changes from 17.10 to 18.04, so I expect you to have a pretty reasonable time of it.

Solution 2:

It really depends on what you have installed. In general, I've come to prefer fresh installations of new OS versions rather than upgrading. There are a ton of fancy deployment and CM tools out there, and OS upgrades in general are complex operations even on "vanilla" installs.

Perhaps take a snapshot and try. Just make sure you can roll back quickly somehow.