A cluster is a group of interconnected computers or nodes that work together to provide higher availability, more computing power, or distributed storage. Instead of relying on a single server, a cluster allows workloads to be spread across multiple machines, improving fault tolerance and scalability. Clusters are used for container orchestration, databases, analytics workloads, and large-scale applications.
Why it matters
Clusters ensure that if one node fails, others can continue handling work. This improves reliability for applications that require continuous uptime. Many modern systems—including Kubernetes, distributed databases, and caching systems—depend on clustering to coordinate large workloads.
Examples
A Kubernetes cluster running multiple containers across worker nodes is a typical example. Distributed systems like Redis Cluster or Elasticsearch also rely on cluster architectures. See the lesson Finding Bottlenecks to understand how distributed setups improve throughput.