Table of Contents

Galera Cluster for MySQL 8.0.42-26.23 and 8.4.5-26.23: Complete Technical Guide

Introduction

The latest release of Galera Cluster 4 for MySQL brings significant improvements with versions 8.0.42-26.23 and 8.4.5-26.23, released on June 24, 2025 ¹. This comprehensive guide explores the technical features, installation process, and optimization strategies for implementing high-availability MySQL clusters using the newest Galera technology.

What’s New in Galera Cluster 4.23

Enhanced Node Management

The Galera replication library 4.23 introduces more robust node leave and shutdown mechanisms by ensuring pending messages are sent before cluster connections are terminated ². This improvement significantly reduces the risk of data inconsistencies during planned maintenance or unexpected node failures.

CMake 4.0.0 Support

Developers can now use CMake 4.0.0 for building Galera Cluster, providing better compatibility with modern development environments ².

Advanced Features

The latest release includes several enterprise-grade features:

XA transaction support for distributed transactions
Encrypted GCache for enhanced security
ARM64 architecture support ³⁴

MySQL 8.4 LTS Integration

Dual Version Support

Galera Cluster now supports both MySQL 8.0.42-26.23 and the new MySQL 8.4.5-26.23 LTS variant ². The MySQL 8.4 version represents the first Long Term Support release in this series, making it ideal for enterprise deployments requiring extended support lifecycles.

Unified Replication Library

Both MySQL versions utilize the same Galera replication library 4.23, ensuring consistent behavior and feature parity across different MySQL versions ⁵².

High Availability Architecture

Synchronous Multi-Master Replication

Galera Cluster provides synchronous multi-master database clustering, ensuring data consistency across all nodes ⁶. Unlike traditional master-slave setups, every node can accept both read and write operations simultaneously.

Comparison with InnoDB Cluster

MySQL 8.4 offers two primary high-availability solutions: Galera Cluster and MySQL InnoDB Cluster ⁷. While InnoDB Cluster provides single-primary and multi-primary modes, Galera Cluster offers virtually synchronous replication with automatic conflict resolution.

Technical Implementation

Installation Requirements

For Ubuntu 22.04 LTS (Jammy Jellyfish) installations, ensure proper MySQL shared compatibility libraries are configured ⁸⁹. CentOS 7, RHEL 7, and RHEL 8 are also supported platforms ¹⁰.

Key Configuration Parameters

-- Enable wsrep provider
wsrep_provider = /usr/lib/galera/libgalera_smm.so

-- Cluster configuration
wsrep_cluster_name = "galera_cluster"
wsrep_cluster_address = "gcomm://node1,node2,node3"

-- Node configuration
wsrep_node_name = "node1"
wsrep_node_address = "192.168.1.10"

Protocol Compatibility

The GCS protocol version has been updated in recent releases, making rolling downgrades impossible after cluster-wide upgrades ¹¹¹². Plan upgrade strategies accordingly to avoid compatibility issues.

Performance Optimization

Streaming Replication

Galera Cluster supports streaming replication for large transactions exceeding 2GB, enabling unlimited transaction sizes ¹³¹⁴. This feature is crucial for applications requiring bulk data operations.

Sequential Consistency Parameters

The Galera replication library 4.22 introduced application-defined sequential consistency parameters, allowing fine-tuned control over replication behavior ¹⁵.

Read-Write Split with MaxScale

Implement MariaDB MaxScale for intelligent read-write splitting, optimizing query distribution across cluster nodes ⁶.

Security Enhancements

Encrypted GCache

The latest release includes encrypted GCache functionality, protecting sensitive data during replication processes ³⁴.

OpenSSL 3.0 Compatibility

Full compatibility with OpenSSL 3.0 ensures modern encryption standards and security protocols ¹⁶.

Keyring Vault Integration

Support for keyring_vault plugin enables secure key management for encryption at rest ¹⁶.

Monitoring and Management

Atomic wsrep_ready Status

The wsrep_ready variable is now atomic, providing more reliable cluster status monitoring ¹¹.

GTID Handling

Improved Global Transaction Identifier (GTID) handling enhances replication tracking and recovery procedures ¹³.

Migration and Upgrade Strategies

From Galera Cluster to Enterprise Edition

Organizations can upgrade from standard Galera Cluster to Enterprise Edition for additional features like enhanced ARM64 support and advanced GCache encryption ³.

Version Compatibility

Ensure proper testing when upgrading between major versions, as protocol changes may affect cluster behavior ¹¹¹².

Best Practices

Cluster Sizing

Deploy odd-numbered node clusters (3, 5, 7) to avoid split-brain scenarios and ensure proper quorum management.

Network Configuration

Configure dedicated network interfaces for cluster communication to minimize latency and maximize throughput.

Backup Strategies

Implement regular backup procedures using tools compatible with Galera’s multi-master architecture.

Troubleshooting Common Issues

Transaction Conflicts

Monitor for certification failures and implement proper retry logic in applications to handle optimistic concurrency control conflicts.

Node Recovery

Utilize the improved node leave and shutdown mechanisms to ensure clean cluster operations during maintenance windows.

Conclusion

Galera Cluster for MySQL 8.0.42-26.23 and 8.4.5-26.23 represents a significant advancement in MySQL high-availability clustering technology. With enhanced security features, improved node management, and support for both current and LTS MySQL versions, this release provides enterprise-grade solutions for mission-critical database deployments.

The combination of synchronous replication, multi-master capabilities, and advanced features like streaming replication and encrypted GCache makes Galera Cluster an excellent choice for organizations requiring zero-downtime database operations with strong consistency guarantees.