So, I've been toying around with Vagrant (version 0.8.2) for the past few days, trying to get it up and running. If it isn't Ruby crashing my machine by causing kernel panics, it's the latest version of VirtualBox (version 4.1), which is required by the latest version of Vagrant. I've discovered that Vagrant, when randomly crashing, doesn't always properly teardown the active VMs it creates. Naturally, this hogs up resources and you end up wondering why your machine performs slower and slower over time.
You might say to yourself, "Well, I could just hop into the VirtualBox GUI and turn them off manually." But, nay, that does not work as Vagrant locks the sessions of its VMs when not running in GUI mode. So, you're left with
x amount of VMs listed right before your eyes with no way of shutting them down. Obviously, you could manually kill the process from Terminal.App or through Activity Monitor, but I've discovered a much easier way.
VirtualBox comes packaged with a command line management system called
VBoxManage. You can use this command to manually force the termination of hung (lol, "hung") VMs.
It's insanely easy. Check it out...