Gitlab: Force non-interactive restore from backups?

Yes; set the environment variable force to yes for the rake process.

With this syntax should work:

sudo gitlab-rake gitlab:backup:restore BACKUP=<BACKUP_ID> force=yes

Similar to both Ash Wilson's and Andrés Cuadros Suárez's answers, I found the following also works (prepend with sudo if required)

gitlab-backup restore force=yes