The Inevitability of a Microservices Architecture Crisis for Transactional Systems and a Radical Way Out

This paper argues that, for the class of transactional systems, microservices architecture (MSA)inevitably enters a containment crisis: the cost of maintaining consistency andfault tolerance outpacesgrowth in both the number of services and useful functionality. The notion of a transactional MSAis introduced. From the semantics of a transactional operation it follows that the coordination graphcannot be a forest of independent components; otherwise the inter-service fabric is redundant. Containment along edges and multi-hop paths drives outpacing growth in containment cost. It is shownthat the monolith bottleneck—the state-transition serialization point—is removed by MSA only forindependent domains and is reproduced under transactional coupling (coordinator, primary, quorumleader). The radical way out is to move containment of coordination and serialization to the protocollayer: an auto-sharded Byzantine fault-tolerant Layer-1 (L1) blockchain with smart contracts. The alternatives “a single DBMS” and “a conventional HA cluster” are rejected as a return to a monolithiccore and/or a privileged control plane.