The service needs to be fit for use, it needs to provide a consistent level of service, in terms of service hours, in terms of capacity and also availability. We need to set aside some design time to develop internal processes, such as change management that lies on top of business value. We need to think about the actual business process and the tools. By tools we mean system management tools, monitoring, asset management, patch management, configuration management, ticketing systems and so on and so forth..
When we think of warranty, we usually think of a 'guarantee' that certain features of an entity or service sold is as accurately stated or legally implied by the seller. In ITIL we associate warranty with the actual service being provided. If we describe a service to a consumer, then the consumer will expect exactly that level of service. They will expect certain conditions to happen or be true. As consumers, we always expect what we pay for will be delivered. The SLA is an example of a particular warranty - its a binding agreement on the level of service the service provider will provide.
A breach of warranty occurs when the level of service agreed, falls short of the mark. Consumers also expect warranty of fitness for a particular purpose. For example, the consumer will trust the provider to select the goods or service to fit a particular request.