SURE: Secure Unikernels Make Serverless Computing Rapid and Efficient

Current serverless platforms introduce non-trivial overheads when chaining and orchestrating loosely-coupled microservices. Containerized function runtimes are also constrained by insufficient isolation and excessive startup time. This motivates our exploration of a more efficient, secure, and rapid serverless design. We describe SURE, a unikernel-based serverless framework for fast function startup, equipped with a high-performance and secure data plane. SURE's data plane supports distributed zero-copy communication via the seamless interaction between zero-copy protocol stack (Z-stack) and local shared memory processing. To establish a lightweight service mesh, SURE uses library-based sidecars instead of individual userspace sidecars. We leverage Intel's Memory Protection Keys (MPK) as a lightweight capability to ensure safe access to the shared memory data plane. It also isolates the Trusted Computing Base (TCB) components in SURE's function runtime (e.g., library-based sidecar, scheduler, etc) from untrusted user code, while preserving the efficient single-address-space nature of unikernels. In particular, SURE prevents unintended privilege escalation involving MPK with an enhanced TCB. These combined efforts create a more secure and robust data plane while improving throughput up to 79X over Knative, a representative open-source serverless platform.