A service level contract is an agreement between two or more parties, one being the customer and other service providers. It may be a formal or informal legally binding ”treaty” (for example. B internal relations within the department). The agreement may include separate organizations or different teams within an organization. Contracts between the service provider and other third parties are often referred to as SLAs (wrongly) – the level of service having been set by the (main) customer, there can be no ”agreement” between third parties; these agreements are simply ”contracts.” However, operational agreements or olea agreements can be used by internal groups to support ALS. If an aspect of a service has not been agreed with the customer, it is not an ”ALS.” Since the late 1980s, SLAs have been used by fixed-line operators. Today, ALS is so widespread that large organizations have many different ALSs within the company itself. Two different units in an organization script an ALS, one unit being the customer and another the service provider. This helps maintain the same quality of service between different units of the organization and in several sites within the organization. This internal ALS script also compares the quality of service between an internal service and an external service provider.  The fundamental advantage of cloud computing is the sharing of resources, supported by the underlying nature of a common infrastructure environment.
SLAs therefore extend to the cloud and are offered by service providers as a service-based contract and not as a customer-based agreement. Measuring, monitoring and covering cloud performance is based on the final UX or its ability to consume resources. The disadvantage of cloud computing compared to ALS is the difficulty of determining the cause of service outages due to the complex nature of the environment. Because applications are moved from dedicated hardware to the cloud, they must reach the same level of service, or even more sophisticated than conventional installations.