How to take a backup of Ansible tower?
All you need is a backup of the postgres database and the projects (to be safe but they should be rebuildable by pulling them again from your VCS in most cases).


Exporting an ovf of you full vm is really an overkill IMHO.
Copying the volumes (pgdata and projects) is by far the simplest solution (the one I actually use). You simply have to put the folders back in place, and docker-compose up -d the correct version and you are set. But to make sure your backup is consistent, you need to stop AWX before copying the dirs, especially for postgres. 
Dumping the postgres database and copying the projects will let you do a backup while AWX is running. For your recovery, you will have to first pop-up a posgres container and reinject the dump before starting all the other containers.


Keep in mind that AWX is the dev version of Tower. As such, there is no real "recommendation" for backups. So the above explanation simply reflect my own experience with AWX. The commercial Tower version embarks the backup in it's deployment playbook. I have never played with it.

If you did not experienced with an AWX upgrade yet, you should be aware that they are sometimes working but can be a real pain (export from old version / import to new version / re-set all the user passwords and jobs credentials). So a backup to quickly rollback when testing the upgrade is vital in this case.

Hope this will help you make a wise choice ;)