Reconfigurable Lattice Agreement and Applications

TL;DR

This paper introduces an asynchronous reconfigurable lattice agreement mechanism that enables consistent system reconfiguration in distributed systems, supporting various data types and abstractions.

Contribution

It presents a novel asynchronous implementation of reconfigurable lattice agreement, extending many distributed data types and abstractions to support dynamic reconfiguration.

Findings

Supports reconfiguration of system states via lattice partial order

Enables reconfigurable versions of max-registers and conflict detectors

Facilitates reconfigurable atomic snapshot and commit-adopt abstractions

Abstract

Reconfiguration is one of the central mechanisms in distributed systems. Due to failures and connectivity disruptions, the very set of service replicas (or servers) and their roles in the computation may have to be reconfigured over time. To provide the desired level of consistency and availability to applications running on top of these servers, the clients of the service should be able to reach some form of agreement on the system configuration. We observe that this agreement is naturally captured via a lattice partial order on the system states. We propose an asynchronous implementation of reconfigurable lattice agreement that implies elegant reconfigurable versions of a large class of lattice abstract data types, such as max-registers and conflict detectors, as well as popular distributed programming abstractions, such as atomic snapshot and commit-adopt.