gitlab-ctl backup-etc is not a command

https://docs.gitlab.com/omnibus/settings/backups.html#backup-and-restore-omnibus-gitlab-configuration is not accurate. Running sudo gitlab-ctl backup-etc returns the following error:

root@ip-172-26-8-187:/etc/gitlab# gitlab-ctl backup-etc
I don't know that command.
omnibus-ctl: command (subcommand)
check-config
  Check if there are any configuration in gitlab.rb that is removed in specified version
deploy-page
  Put up the deploy page
diff-config
  Compare the user configuration with package available configuration
prometheus-upgrade
...