Aqua is something like Docker but for Urbit; it is a virtualization tool whose primary purpose is testing and development.

Aqua is a Gall app that runs an Arvo instance or instances in userspace. It pretends to be Vere, and as such it loads Pills to boot up a virtual ship or fleet of ships and then manages them from within the parent Arvo instance. Running tests for a virtual fleet of Aqua ships is done using pH.

Aqua is jetted with the usual Nock interpreter and thus virtual ships do not run any slower than the parent ship.

Further Reading