Cloud computing is a set of IT services that are provided to a customer over a network based on SLA. Cloud services can scale up or down their service as per requirements. Using cloud computing, Customer can use computer resources through internet based on service level agreement. In cloud computing customer does not aware about cost of hardware deployment, software licenses and system maintenance etc. There are various research challenges for adopting cloud computing such as Service Level Agreement (SLA), security, interoperability and reliability.