Whether it's one VM or multiple, you still have to write the configuration management code (Puppet modules, Ansible roles...) to do so, and some of them will ne

Whether it's one VM or multiple, you still have to write the configuration management code (Puppet modules, Ansible roles...) to do so, and some of them will need tweaking for specific applications (e.g. in Python, installing libxml or libmysqlclient for pip dependencies, in PHP installing the various dynamically loaded extensions), which is where the rabbithole of complexity begins.