Ubuntu LTS Patch Mgmt?

Hello All,

I recently joined a company that uses Ubuntu Server for the OS in their stack; I've come from mainly a EL background and used spacewalk to patch boxes before. I know spacewalk debian support is dodgy at best and was wondering if anyone manages a significant amount of Ubuntu server (50+) and what they are using. I don't think I'll be able to get Landscape due to licensing costs, I'd prefer something open source.

Thanks!