3.1 CLOUD SIM

CloudSim: Introduction to Simulator, understanding CloudSim simulator, CloudSim Architecture(User code, CloudSim, GridSim, SimJava) Understanding Working platform for CloudSim,

CloudSim
CloudSim is an open-source framework, which is used to simulate cloud computing infrastructure and services. 
It is developed by the CLOUDS Lab organization in 2009 and is written entirely in Java. 
It is used for modelling and simulating a cloud computing environment as a means for evaluating a hypothesis prior to software development in order to reproduce tests and results.

For example, if you were to deploy an application or a website on the cloud and wanted to test the services and load that your product can handle and also tune its performance to overcome bottlenecks before risking deployment, then such evaluations could be performed by simply coding a simulation of that environment with the help of various flexible and scalable classes provided by the CloudSim package, free of cost.  

Open source and free of cost, so it favours researchers/developers working in the field.

Easy to download and set-up.

It is more generalized and extensible to support modelling and experimentation.

Does not require any high-specs computer to work on.

Provides pre-defined allocation policies and utilization models for managing resources, and allows implementation of user-defined algorithms as well.

The documentation provides pre-coded examples for new developers to get familiar with the basic classes and functions.

Tackle bottlenecks before deployment to reduce risk, lower costs, increase performance, and raise revenue.

Benefits of Simulation over the Actual Deployment:

1. No capital investment involved. With a simulation tool like CloudSim there is no installation or maintenance cost.
2. Easy to use and Scalable. You can change the requirements such as adding or deleting resources by changing just a few lines of code.
3. Risks can be evaluated at an earlier stage. In Cloud Computing utilization of real testbeds limits the experiments to the scale of the testbed and makes the reproduction of results an extremely difficult undertaking. With simulation, you can test your product against test cases and resolve issues before actual deployment without any limitations.
4. No need for try-and-error approaches. Instead of relying on theoretical and imprecise evaluations which can lead to inefficient service performance and revenue generation, you can test your services in a repeatable and controlled environment free of cost with CloudSim.
5. CloudSim provides support for simulation and modelling of:
   Large scale virtualized Datacenters, servers and hosts.
6. Customizable policies for provisioning host to virtual machines.
7. Energy-aware computational resources.
8. Application containers and federated clouds (joining and management of multiple public clouds).
9. Datacenter network topologies and message-passing applications.
10. Dynamic insertion of simulation entities with stop and resume of simulation.
11. User-defined allocation and provisioning policies.
    
    

CloudSim Architecture(User code, CloudSim, GridSim, SimJava)

CloudSim is built on top of SimJava, a discrete event simulation library in Java. It provides a framework for modeling and simulating cloud computing environments. The architecture of CloudSim involves several key components, including the user code, CloudSim core, and optional GridSim integration.
a. USER CODE
Users develop their simulation scenarios and experiments using Java programming language. They define the cloud infrastructure, workload characteristics, resource provisioning policies, and simulation parameters according to their research or educational objectives.

b. CloudSim Core:

The CloudSim core provides the foundation for modeling and simulating cloud computing environments. It includes several modules and classes for simulating various components of cloud infrastructure, such as datacenters, hosts, virtual machines (VMs), and cloudlets (workload tasks).

CloudSim core also includes support for modeling and simulating cloud computing concepts, such as resource provisioning, scheduling algorithms, energy consumption, and network communication.

The core provides APIs for users to interact with the simulation environment, create and configure cloud infrastructure components, and monitor simulation progress and results.

c. GridSim Integration (Optional):

GridSim is an earlier version of CloudSim that focused on modeling and simulating grid computing environments. While CloudSim is primarily designed for cloud computing, it includes optional integration with GridSim for backward compatibility and interoperability.
Users can leverage GridSim functionalities within CloudSim simulations to model grid computing scenarios, such as resource sharing, job scheduling, and federation of distributed resources.
GridSim integration allows users to reuse existing GridSim-based models, algorithms, and experiments in CloudSim simulations, providing a seamless transition from grid computing to cloud computing research.

d. SimJava

SimJava is a discrete event simulation library written in Java. It provides a framework for building simulations of dynamic systems where events occur at discrete points in time. SimJava is designed to be flexible, efficient, and easy to use, making it suitable for a wide range of simulation applications, including modeling computer systems, networks, manufacturing processes, and more.