I manage multiple apps in my dev:
/var/www/ qa jt auth
We have a QA vagrant which runs QA app in its own vagrant. My understanding was that each app would run its own VM but this would cause some issues such as: some apps require other apps to functions - for example, QA requires Auth to authenticate to fully use the app - to allow this, the provision script will install an instance of Auth in its filesystem; alternatively, if we were to run multiple VMs for each app required to run (e.g. QA VM and Auth VM) this would be a drain on the host machine I wonder.
So I'm considering having a single VagrantFile that sits within /var/www. When we
vagrant up from this location it will install all the apps - jt, qa, auth, etc. As this will be the synced_folder (/var/www) we can also edit any app in our preferred text editors from the host. This may be useful for all developers and we only need to manage one VagrantFile and provision script (and other app-specific config files I'm sure that each developer could manage for their apps).
This means that the VagrantFile wouldn't be part of each app repo which is a bit of a downside perhaps. Anyway just wondering if this is common, before I start experimenting, encase there are good reason not to do this.