Pregunta de System Administration #019e3a4f

Horizontal scaling, also known as scaling out, refers to adding or removing instances of the same application to handle changes in demand. This is typically done by increasing or decreasing the number of application replicas running across a cluster of nodes. The correct description is "adding/removing application instances of the same application to meet demand."

How it Works

In a horizontally scaled architecture, each application instance is a separate process, often running in its own container or on a separate virtual machine. A load balancer distributes incoming traffic across these instances. When demand increases, new instances are started; when demand decreases, excess instances are terminated. This approach improves fault tolerance and allows for near-linear scalability.

Why the Correct Value is Right

The phrase "adding/removing application instances of the same application" precisely captures the essence of horizontal scaling. It emphasizes that the application itself remains unchanged, but the number of its running copies is adjusted. This is the standard definition used in cloud computing and container orchestration platforms like Kubernetes, where scaling a deployment means changing the replica count.

Why the Incorrect Values are Wrong

• "Adding/removing node instances to the cluster" describes scaling the infrastructure (cluster nodes), not the application. While adding nodes can enable horizontal scaling, it is not the direct act of scaling the application deployment.
• "Adding/removing applications" is ambiguous and could refer to deploying different applications, not scaling a single application.
• "Adding/removing resources to application instances" describes vertical scaling (scaling up), where you increase CPU, memory, or other resources to an existing instance, rather than adding more instances.