Q: How does cloudooo define the handler to convert a PDF?
A: Cloudooo uses mimetype to map it and it is defined in cloudooo.conf, under mimetype_registry property. For example:
application/pdf * pdf
image/* image/* imagemagick
In this configuration, the first line means, all convertions from PDF to any format will use PDF handler and all images will use ImageMagick handler.
Important: priority matters, first match take precedence on next lines.
Q: Can I setup multiple instances of Cloudooo?
A: Yes, you can. After deploy all instances, you can setup a HAProxy in the front of them. In SlapOS, there is a profile that does all configuration to get a cluster of Cloudooo. If you don't have an user account, you can follow the steps here.
After register and access you dashboard, you can request a Cloudooo service and set how many instance you want.