PreC-Raft:一种引入预备候选者的共识算法

PreC Raft:A Consensus Algorithm for Introducing Pre Candidate

为了解决Raft共识算法中由于网络隔离现象导致的节点无法与集群其他节点正常通信,从而在恢复通信后参与领导者选举影响系统共识效率的问题,文中提出了一种引入预备候选者(PreC-Raft)的改进Raft共识算法,引入了过时节点的概念,并增加了一种预备候选者的角色状态,其发起的PreC RPC消息用以执行选举正式候选者阶段的资格审查功能。实验结果表明,改进后的算法在集群出现过时节点时,可以做到节约54.82%的选举耗时以及降低14.21%的共识时延。针对出现网络隔离“孤岛”的异常情况,改进后的PreC-Raft算法能够满足更极端的网络环境。

Due to network isolation,nodes in the Raft consensus algorithm cannot communicate normally with other nodes in the cluster,negatively influencing the efficiency of system consensus in the recovery of communication and participation in leader election.To solve the problem,this paper proposes an improved Raft consensus algorithm by introducing a reserve candidate(named as PreC Raft).First,the concept of obsolete nodes is introduced,and a role of Pre Candidate is added so that the PreC RPC messages which a Pre Candidate initiates can be used to perform the qualification function during the phase of official candidate election.The experimental results indicate that 54.82%of election time can be saved and 14.21%of consensus delay will be reduced when there are outdated nodes in the cluster.The improved PreC Raft algorithm can be used in more extreme network environments in case of abnormal network isolation“islands”.