As you consider partnering with a cloud-service provider, you should identify early on who will be responsible for which operations. You may not, for example, want to administer the underlying operating system or database-management system. In such cases, you would select as platform as a service (PaaS) solution or database as a service (DBaaS) solution. At other times, you may want to perform such operations, for which you would select an infrastructure as a service (IaaS) solution. In any case, your responsibilities will break down as follows:
Customer responsibilities
Cloud-service responsibilities
Shared responsibilities
Within your service-level agreement, you should clearly state the responsibility breakdown.