CLOUDSIM TOOLKIT: INTRODUCTION

CloudSim Toolkit

CloudSim is an extensible simulation toolkit or framework that enables modeling, simulation and experimentation of Cloud computing systems and application providing environments. The CloudSim toolkit supports both system and behavior modeling of Cloud system components. 

Basic components of CloudSim

1. Datacenter
   Data center is used to model the core services at the system level of a cloud infrastructure. It consists of a set of hosts which manage a set of virtual machines whose tasks are to handle "low level" processing, and at least one data center must be created to start the simulation.Datacenter class is a CloudResource whose hostList are virtualized. It deals with processing of VM queries instead of processing Cloudlet-related queries. So, even though an AllocPolicy will be instantiated in the init() method of the superclass, it will not be used, as processing of cloudlets are handled by the CloudletScheduler and processing of VirtualMachines are handled by the VmAllocationPolicy.
2. Host
   This component is used to assign processing capabilities (which is specified in the milion of instruction per second that the processor could perform), memory and a scheduling policy to allocate different processing cores to multiple virtual machines that is in the list of virtual machines managed by the host.
3. Virtual Machines
   This component manages the allocation of different virtual machines different hosts, so that processing cores can be scheduled (by the host) to virtual machines. This configuration depends on particular application, and the default policy of the allocation of virtual machines is "first-come, first-serve".
4. Datacenter broker
   The responsibility of a broker is to meditate between users and service providers, depending on the requirement of quality of service that the user specifies. In other words, the broker will identify which service provider is suitable for the user based on the information it has from the Cloud Information Service, and negotiates with the providers about the resources that meet the requirement of the user. The user of CloudSim needs to extend this class in order to specify requirement in their experiments.
5. Cloudlet
   This component represents the application service whose complexity is modeled in CloudSim in terms of the computational requirements.
6. CloudCoordinator
   This component manages the communication between other CloudCoordinator services and brokers, and also monitor the internal state of a data center which will be done periodically in terms of the simulation time.