Collegenote
- Defining the Cloud
- Cloud Computing
- Emergence of Cloud Computing
- Cloud Based Service Models
- Grid Computing or Cloud Computing
- Components of Cloud Computing
- Cloud Computing Deployment Models
- Benefits of using cloud models
- Legal Issues in Using Cloud Models
- Ethical issues in cloud computing
- Characteristics of Cloud Computing
- Evolution of cloud computing
- Challenges for cloud computing
- Grid Computing
- Distributed Computing in Grid and Cloud
- Cloud Communication
- Communication-as-a-Service (CaaS)
- Advantages of CaaS
- Infrastructure-as-a-Service (IaaS)
- Popular IaaS solutions
- Modern On-Demand Computing
- Amazon’s Elastic Cloud
- Amazon EC2 Service Characteristics
- Elastic IP Addressing
- Monitoring-as-a-Service (MaaS)
- The Traditional On-Premises Model
- Platform-as-a-Service (PaaS)
- Key Characteristics of PaaS
- Software-as-a-Service
- SaaS Implementation Issues
- The key characteristics of SaaS
- Benefits of SaaS Model
- Jericho Cube Model
- XaaS
- Evolution from Managed service providers (MSP) to Cloud Computing
- Single Purpose architectures to multi-purpose architectures
- Service Oriented Architectures (SOA)
- Combining Cloud and SOA
- Characterizing SOA
- Open Source Software in Data Centers
- Data center virtualization
- Cloud data center
Challenges for cloud computing #
The development of efficient cloud applications inherits the challenges posed by the natural imbalance between computing, I/O, and communication bandwidths of physical systems; these challenges are greatly amplified due the scale of the system, its distributed nature, and by the fact that virtually all applications are data-intensive. Though cloud computing infrastructures attempt to automatically distribute and balance the load, the application developer is still left with the responsibility to place the data close to the processing site and to identify optimal storage for the data. One of the main advantages of cloud computing, the shared infrastructure, could also have a negative impact as perfect performance isolation is nearly impossible to reach in a real system, especially when the
system is heavily loaded. The performance of virtual machines fluctuates based on the load, the infrastructure services, the environment including the other users. Reliability is also a major concern; node failures are to be expected whenever a large numbers of nodes cooperate for the computations. Choosing an optimal instance, in terms of performance isolation, reliability, and security, from those offered by the cloud infrastructure is another critical factor to be considered. Of course, cost considerations play also a role in the choice of the instance type. Many applications consist of multiple stages; in turn, each stage may involve multiple instances running in parallel on the systems of the cloud and communicating among them. Thus, efficiency, consistency, and communication scalability of communication are major concerns for an application developer. Indeed, due to shared networks and unknown topology, cloud infrastructures exhibit inter-node latency and bandwidth fluctuations which affect the application performance.
The following are some of the notable challenges associated with cloud computing, and although some of these may cause a slowdown when delivering more services in the cloud, most also can provide opportunities, if resolved with due care and attention in the planning stages.
- Security and Privacy — Perhaps two of the more “hot button” issues surrounding cloud computing relate to storing and securing data, and monitoring the use of the cloud by the service providers. These issues are generally attributed to slowing the deployment of cloud services. These challenges can be addressed, for example, by storing the information internal to the organization, but allowing it to be used in the cloud. For this to occur, though, the security mechanisms between organization and the cloud need to be robust and a Hybrid cloud could support such a deployment.
- Lack of Standards — Clouds have documented interfaces; however, no standards are associated with these, and thus it is unlikely that most clouds will be interoperable. The Open Grid Forum is developing an Open Cloud Computing Interface to resolve this issue and the Open Cloud Consortium is working on cloud computing standards and practices. The findings of these groups will need to mature, but it is not known whether they will address the needs of the people deploying the services and the specific interfaces these services need. However, keeping up to date on the latest standards as they evolve will allow them to be leveraged, if applicable.
- Continuously Evolving — User requirements are continuously evolving, as are the requirements for interfaces, networking, and storage. This means that a “cloud,” especially a public one, does not remain static and is also continuously evolving.
- Compliance Concerns — The Sarbanes-Oxley Act (SOX) in the US and Data Protection directives in the EU are just two among many compliance issues affecting cloud computing, based on the type of data and application for which the cloud is being used. The EU has a legislative backing for data protection across all member states, but in the US data protection is different and can vary from state to state. As with security and privacy mentioned previously, these typically result in Hybrid cloud deployment with one cloud storing the data internal to the organization.