  We present Project Florida, a system architecture and software development
kit (SDK) enabling deployment of large-scale Federated Learning (FL) solutions
across a heterogeneous device ecosystem. Federated learning is an approach to
machine learning based on a strong data sovereignty principle, i.e., that
privacy and security of data is best enabled by storing it at its origin,
whether on end-user devices or in segregated cloud storage silos. Federated
learning enables model training across devices and silos while the training
data remains within its security boundary, by distributing a model snapshot to
a client running inside the boundary, running client code to update the model,
and then aggregating updated snapshots across many clients in a central
orchestrator. Deploying a FL solution requires implementation of complex
privacy and security mechanisms as well as scalable orchestration
infrastructure. Scale and performance is a paramount concern, as the model
training process benefits from full participation of many client devices, which
may have a wide variety of performance characteristics. Project Florida aims to
simplify the task of deploying cross-device FL solutions by providing
cloud-hosted infrastructure and accompanying task management interfaces, as
well as a multi-platform SDK supporting most major programming languages
including C++, Java, and Python, enabling FL training across a wide range of
operating system (OS) and hardware specifications. The architecture decouples
service management from the FL workflow, enabling a cloud service provider to
deliver FL-as-a-service (FLaaS) to ML engineers and application developers. We
present an overview of Florida, including a description of the architecture,
sample code, and illustrative experiments demonstrating system capabilities.
