[TriLUG] Open source software to monitor hundreds of VMs

[Ron Kelley via TriLUG]

Looking for some suggestions on Open Source software to monitor hundreds of VMs and/or containers (99% Linux [Ubuntu/CentOS]).  Currently using Cacti, but it is very tedious to setup a new VM.  Would like to get the “typical” stats (CPU, RAM, HDD, Network, SWAP, etc).  GUI would be nice as well as an API to add new VMs and extract data.

Thanks.