It is my understanding that containers are much more lightweight than VMs because they do not virtualize the hardware but instead just isolate the software running in them from software running in other containers on the system.
My situation is such that I cannot afford to purchase additional servers, and the servers I do have are all running hypervisors. I need to provision at least 6 "servers" to host instances of relatively small web application (each instance is for a different customer). It would be wasteful to provision a new VM for each of these servers, so I plan to set up 2 VMs and do one of the following:
- Run multiple instances of the application on each VM using virtual hosts (apache). or
- Set up containers on the VMs which would allow me to isolate the environments.
Considering this, is there a non-negligible overhead associated with container systems that would make it a bad idea to use them inside a VM, or is there any other technical reason why I would not want to use containers?