Leaderless Consistency Protocol for Distributed Clusters

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Solution Overview

Problem

Conventional distributed computing systems with a cluster leader suffer from performance bottlenecks and downtime due to leader election processes and two-phase commit protocols, leading to complexity and reduced scalability and availability.

Innovation Solution

A leaderless cluster system where any node can initiate a write operation, using a sequence number validation mechanism to ensure data consistency across nodes, allowing for simultaneous writes and a supermajority vote to confirm successful operations, eliminating the need for a centralized leader and reducing downtime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a centralized leader is used to coordinate write operations, then consistency can be maintained, but performance degrades due to the leader becoming a bottleneck

Engineering Contradiction:
Improvedata consistencyVSAvoidwrite operation performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent removes the centralized leader role from the system entirely. Instead of extracting the leader's coordination function to a separate component, it distributes the write operation capabilities to all nodes equally, allowing any node to initiate writes without needing leader approval or coordination.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the write operation process into independent phases that can be executed concurrently by multiple nodes. Rather than having a single leader sequence all operations, each node can independently propose, validate, and commit writes using sequence numbers and version vectors to maintain consistency without centralized coordination.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a leader election process is implemented to handle leader failure, then system availability is maintained, but downtime occurs during the election process

Engineering Contradiction:
Improvesystem availabilityVSAvoiddowntime during leader election
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent completely removes the leader election mechanism from the system. By eliminating the leader role entirely, there is no need for election processes, and the system maintains continuous operation without any election-related downtime or availability interruptions.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a two-phase commit protocol is used to ensure consistency, then data integrity is maintained, but system complexity increases

Engineering Contradiction:
Improvedata integrityVSAvoidprotocol complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the fundamental parameters of the commit protocol by replacing the two-phase approach with a continuous phase system using sequence numbers and version vectors. Instead of distinct prepare and commit phases with complex coordination, nodes use monotonically increasing sequence numbers and vector clocks to automatically determine commit order and maintain consistency with simpler logic.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If majority votes are required for each write operation, then consistency is ensured, but write performance decreases due to coordination overhead

Engineering Contradiction:
ImproveconsistencyVSAvoidwrite operation speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by having nodes pre-establish sequence numbers and version vectors before write operations occur. These pre-computed parameters allow nodes to quickly determine commit validity without real-time voting or coordination, enabling faster writes while maintaining consistency through the pre-set ordering information.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3326065B1Leaderless consistency protocol
Publication Date: 2023.05.31 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3326065B1 patent drawingFigure 1
  • EP3326065B1 patent drawingFigure 2~3
  • EP3326065B1 patent drawingFigure 4a

AI summary

Systems and methods are provided for processing requests, received from clients and peer nodes, in a leaderless cluster of nodes. A node can initiate a read or a write operation in the cluster. The node can solicit votes from its peer nodes in order to confirm that the requested operation should be performed. A threshold number of positive responses, such as a supermajority of the nodes in the cluster, can be required in order to confirm the requested operation.