Cloud computing aims to make a large selection of sophisticated technologies available to users for deployment and migration. In reality, once a cloud service provider has been chosen, migration is often a costly and time-consuming process. This paper presents MultiBox, a lightweight container technology that facilitates flexible vendor-independent migration. Our framework allows its users to deploy and migrate almost any application in its normal state with minimal computational and network resource overheads. We show that the performance overhead of deploying within a lightweight container is 4.90% of the resources available to an average VM and downtime during a migration is less than the time needed to scale a server using provider-centric tools.