Definition
Cluster hardening is the process of securing a group of interconnected computers, known as a cluster, against unauthorized access and cyber threats. This involves implementing a series of security controls and configurations to minimize the attack surface and protect shared resources and data. In practice, it entails applying security best practices to each node within the cluster, as well as the network interconnecting them, ensuring consistent protection. This is crucial for maintaining the availability and integrity of critical applications and services that rely on cluster technology. For example, hardening a high availability cluster for a database involves restricting network access to only necessary ports and implementing strong authentication for all cluster management operations. Unlike general system hardening, cluster hardening specifically addresses the unique vulnerabilities of distributed systems and inter-node communication. This concept is particularly relevant for security certifications like CompTIA Security+ and CySA+.