Hello,

Maybe you can enable Centreon Backup (sql dump and conf files) in the UI, and then lauch a S3 Sync 
Never did it, but i think with some S3 cmd tool (like S3cmd) and cron, you can do it

Centreon have a local backup system which store database's dumps (if you choose the option) and config files. This backups are stored on /var/cache/centreon/backup

What you can do:
- Config the Centreon backup from the UI (Administration>Parameters>Backup) with the Dump type
- Install s3 cmd tool
- Set up cron file to execute the s3 cmd tool on the same days of the backups to sync backups on the S3

I'm not sure if it will works as you intend, but i hope it give you some hints to do it

Regards,