This Virtual Machine image is a lightweight install of Ubuntu 18.04 LTS, with the pebble tooling and SDK preinstalled. It also comes with Atom installed for developing on the device.
The default username and password is pebble/pebble. Please change the password once you've logged in for the first time. The image is provided as a .vmdk file, so it will work with virtualbox and vmware.
If you need a VM player, virtualbox is a free option: