The aim of this guide is to provide a practical reference to help enterprise information technology (IT) and business decision makers as they analyze and consider service level agreements (SLA) from different cloud service providers. The paper gives guidance to decision makers on what to expect and what to be aware of as they evaluate SLAs from their cloud computing providers. A checklist of key criteria for evaluating and comparing SLAs from different providers is included. Additionally, this paper highlights the role that standards play to improve interoperability and comparability across different cloud providers, and identify areas where future standardization could be effective.
SLAs are important to clearly set expectations for service between the cloud consumer (buyer) and the cloud provider (seller). Each cloud entity engaged by the enterprise should have a cloud SLA defined, including: cloud provider, cloud carrier, cloud broker and even cloud auditor. Consideration must also be given to the different models of service delivery: Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS) as each model brings different requirements. This paper focuses primarily on the SLA details between the cloud consumer and cloud provider, and focuses on the requirements that are common across the various service models (emphasis is given to the IaaS service model since SLAs are more advanced in this area).
This paper prescribes a series of ten steps that cloud consumers should take to evaluate cloud SLAs in order to compare public cloud service providers or negotiate terms with a provider. The following steps are discussed in detail:
- Understand roles and responsibilities
- Evaluate business level policies
- Understand service and deployment model differences
- Identify critical performance objectives
- Evaluate security and privacy requirements
- Identify service management requirements
- Prepare for service failure management
- Understand the disaster recovery plan
- Define an effective management process
- Understand the exit process
This document is an extension of the Practical Guide to Cloud Computing white paper.