Which technique does a virtualization vendor use to allow host clusters to scale and manage computing resources without service disruption?

The technique of distributed resource scheduling is crucial for virtualization vendors because it enables the seamless allocation and management of computing resources across multiple hosts in a cluster. This method allows for a dynamic adjustment of resources based on demand while maintaining service availability.

When employing distributed resource scheduling, the system continuously assesses workload requirements and can redistribute resources in real-time. This means that as workloads fluctuate, computing power can be scaled up or down without interrupting ongoing services. By efficiently balancing the load across available servers, this technique helps avoid bottlenecks that can occur if one server becomes overutilized while others are underutilized.

In contrast, while resource scheduling can refer to allocating resources based on predefined rules, it might not effectively handle dynamic workloads across multiple hosts. Resource optimization focuses on improving the efficiency of resource usage but does not necessarily address the need for continuous operation during scaling. Resource sharing generally refers to the concept of multiple systems or users utilizing the same resources but does not specifically pertain to the proactive management of resources in a virtualized environment.

Therefore, distributed resource scheduling stands out as the most effective approach for scaling and managing computing resources in host clusters without causing service disruption.