The Cloud computing is the architecture in which the host, virtual machines, virtual server, and brokers are involved in communication. The Cloud computing has various challenges due to its dynamic architecture. These challenges are virtual machine migration, load balancing, task scheduling and security. The brokers are responsible to assign the cloudlets to the appropriate virtual machine. The selection of the appropriate virtual machine will be decided on the basis of cloudlet which needs to be executed and resources of the virtual machines. The broker is the intermediated party between the virtual machine and the host. The virtual machines are responsible to execute the cloudlets, verify the identity of the host.
The data of the host will be uploaded, deleted or updated on the virtual servers. In the recent time various techniques has been purposes which improved security of the cloud architecture. These proposed techniques are based on encryption, secure authentication mechanism. The challenges of task allocation and load balancing are accomplished by the techniques which are based on genetic algorithm and bio inspired techniques. In the recent times many users are involved in using cloud services due to which the number of virtual servers, virtual machines are increased to satisfy the demand of users. This leads to increase the energy consumption of the cloud architecture. Much research is required to make the cloud architecture energy efficient.