Cloud computing is all the rage. "Itsbecome the phrase du jour,“ -Gartner (senior analyst Ben Pring)
COMPARISON Cloud computing shares characteristics with:• Autonomic computing — Computer systems capable of self-management.• Client–server model — Client–server computing refers broadly to any distributed application that distinguishes between service providers (servers) and service requesters (clients).• Grid computing — "A form of distributed and parallel computing, whereby a super and virtual computer is composed of a cluster of networked, loosely coupled computers acting in concert to perform very large tasks."• Mainframe computer — Powerful computers used mainly by large organizations for critical applications, typically bulk data processing such as census, industry and consumer statistics, police and secret intelligence services, enterprise resource planning, and financial transaction processing.• Utility computing — The "packaging of computing resources, such as computation and storage, as a metered service similar to a traditional public utility, such as electricity."• Peer-to-peer — Distributed architecture without the need for central coordination, with participants being at the same time both suppliers and consumers of resources (in contrast to the traditional client–server model).
Characteristics• Agility improves with users ability to re-provision technological infrastructure resources.• Application programming interface (API) accessibility to software that enables machines to interact with cloud software in the same way the user interface facilitates interaction between humans and computers. Cloud computing systems typically use REST-based APIs.• Cost is claimed to be reduced and in a public cloud delivery model capital expenditure is converted to operational expenditure. This is purported to lower barriers to entry, as infrastructure is typically provided by a third-party and does not need to be purchased for one-time or infrequent intensive computing tasks. Pricing on a utility computing basis is fine-grained with usage-based options and fewer IT skills are required for implementation .• Device and location independence enable users to access systems using a web browser regardless of their location or what device they are using (e.g., PC, mobile phone). As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet, users can connect from anywhere.• Virtualization technology allows servers and storage devices to be shared and utilization be increased. Applications can be easily migrated from one physical server to another.• Multi-tenancy enables sharing of resources and costs across a large pool of users thus allowing for: – Centralization of infrastructure in locations with lower costs (such as real estate, electricity, etc.) – Peak-load capacity increases (users need not engineer for highest possible load-levels) – Utilization and efficiency improvements for system
Continued… (2)• Reliability is improved if multiple redundant sites are used, which makes well-designed cloud computing suitable for business continuity and disaster recovery.• Scalability and Elasticity via dynamic ("on-demand") provisioning of resources on a fine- grained, self-service basis near real-time, without users having to engineer for peak loads.• Performance is monitored, and consistent and loosely coupled architectures are constructed using web services as the system interface.• Security could improve due to centralization of data, increased security-focused resources, etc., but concerns can persist about loss of control over certain sensitive data, and the lack of security for stored kernels. Security is often as good as or better than other traditional systems, in part because providers are able to devote resources to solving security issues that many customers cannot afford. However, the complexity of security is greatly increased when data is distributed over a wider area or greater number of devices and in multi-tenant systems that are being shared by unrelated users. In addition, user access to security audit logs may be difficult or impossible. Private cloud installations are in part motivated by users desire to retain control over the infrastructure and avoid losing control of information security.• Maintenance of cloud computing applications is easier, because they do not need to be installed on each users computer and can be accessed from different places.
• Hybrid cloud: It is a composition of two or more clouds (private, community or public) that remain unique entities but are bound together, offering the benefits of multiple deployment models.• Private cloud: Private cloud is cloud infrastructure operated solely for a single organization, whether managed internally or by a third-party and hosted internally or externally.
Whats In The Cloud OS?• An operating system that spans & controls a set of connected servers: – Abstract execution environment – Shared file system – Resource allocation – Programming environments• And more: Utility computing – 24/7 operation – Pay for what you use – Simpler, transparent administration
What Is Windows Azure?• It is an operating system for the cloud• It is designed for utility computing• It provides facilities to: – Write your apps (developer experience) – Host your apps (compute) – Manage your apps (service management) – Store your data (storage)
Storage S c a l a b l e & A va i l a b l e• Simple, essential storage abstractions: – Large items of data: Blobs, file streams, … – Service state: Simple tables, caches, … – Service communication: Queues, locks, …• With an emphasis on: – Massive scale, availability and durability – Geo-location and geo-replication• This is not a relational database in the cloud• cloud services running on Windows Azure will have access to co-located relational database in the cloud – There are multiple target scenarios
Putting It All Together• Example: n m LB Web Role Worker Role Cloud Storage
Windows Azure Is• Designed to encourage best practices – Stateless compute + durable storage – Co-location of computation and data – Queues for asynchronous processing• An open platform – Connect outbound to any server – Open protocols and APIs on all components
Amazon EC2• EC2is a central part of Amazon.coms cloud computing platform, Amazon Web Services (AWS).• EC2 allows users to rent virtual computers on which to run their own computer applications.• A user can create, launch, and terminate server instances as needed, paying by the hour for active servers, hence the term "elastic". EC2 provides users with control over the geographical location of instances that allows for latency optimization and high levels of redundancy
Elastic Compute Unit (ECU)• The Elastic Compute Unit (ECU) was introduced by Amazon EC2 as an abstraction of computer resources.• Amazon’s Definition of ECU notes “We use several benchmarks and tests to manage the consistency and predictability of the performance of an EC2 Compute Unit.• One EC2 Compute Unit provides the equivalent CPU capacity of a 1.0-1.2 GHz 2007 Opteron or 2007 Xeon processor.• It is also the equivalent to an early-2006 1.7 GHz Xeon processor referenced in our original documentation”
Amazon S3• Amazon S3 (Simple Storage Service) is an online storage web service offered by Amazon Web Services. Amazon S3 provides storage through web services interfaces.• S3 is designed to provide 99.999999999% durability and 99.99% availability of objects over a given year.• S3 stores arbitrary objects (computer files) up to 5 terabytes in size, each accompanied by up to 2 kilobytes of metadata.
Operating systems: When it launched in August 2006, the EC2 service offered Linux and later Sun Microsystems Open Solaris and Solaris Express Community Edition. In October 2008, EC2 added the Windows Server 2003 and Windows Server 2008 operating systems to the list of available operating systems. As of December 2010 it has also been reported to run FreeBSD; in March 2011, NetBSD AMIs became available.
Persistent Storage: An EC2 instance may be launched with a choice of two types of storage for its boot disk or root device. The first option is a local "instance-store" disk as a root device (originally the only choice). The second option is to use an EBS volume as a root device EBS volumes provide persistent storage independent of the lifetime of the EC2 instance, and act much like hard drives on a real server. Users can set up and manage storage volumes of sizes from 1GB to 1TB. EBS volumes can be attached or detached from instances while they are running, and moved from one instance to another.
Elastic IP Addresses:* Amazons Elastic IP Address feature is similar to static IP address in traditional data centers, with one key difference. A user can programmatically map an Elastic IP Address to any virtual machine instance without a network administrators help and without having to wait for DNS to propagate the new binding.* In this sense an Elastic IP Address belongs to the account and not to a virtual machine instance* It exists until it is explicitly removed. It remains associated with the account, even while it is associated with no instance.
Amazon Cloud Watch: Amazon Cloud Watch is a Web service that provides real-time monitoring to Amazons EC2 customers on their resource utilization such as CPU, disk and network. Cloud watch does not provide any memory, disk space, or load average metrics. An Amazon engineer has stated that this is due to the requirement to install software in the VM - something they wish to avoid.
Automated Scaling: Amazons Auto Scaling feature of EC2 allows it to automatically adapt computing capacity to site traffic
ISSUES ON CLOUDPrivacy• The cloud model has been criticized by privacy advocates for the greater ease in which the companies hosting the cloud services control, thus, can monitor at will, lawfully or unlawfully, the communication and data stored between the user and the host company• Using a cloud service provider (CSP) can complicate privacy of data because of the extent to which virtualization for cloud processing (virtual machines) and cloud storage are used to implement cloud service.• Cloud computing poses privacy concerns because the service provider at any point in time, may access the data that is on the cloud. They could accidentally or deliberately alter or even delete some info.
Open source:Open-source software has provided thefoundation for many cloud computingimplementations, one prominent examplebeing the Hadoop frameworkOpen standards:Most cloud providers expose APIs that aretypically well-documented (often under aCreative Commons license) but also unique totheir implementation and thus notinteroperable
Security:• As cloud computing is achieving increased popularity, concerns are being voiced about the security issues introduced through adoption of this new model. The effectiveness and efficiency of traditional protection mechanisms are being reconsidered as the characteristics of this innovative deployment model can differ widely from those of traditional architectures.• An alternative perspective on the topic of cloud security is that this is but another, although quite broad, case of "applied security" and that similar security principles that apply in shared multi-user mainframe security models apply with cloud security.• The relative security of cloud computing services is a contentious issue that may be delaying its adoption.
Sustainability:• Although cloud computing is often assumed to be a form of "green computing", there is no published study to substantiate this assumption. Citing the servers affects the environmental effects of cloud computing.• In areas where climate favors natural cooling and renewable electricity is readily available, the environmental effects will be more moderate. (The same holds true for "traditional" data centers.)• Countries with favorable conditions, such as Finland, Sweden and Switzerland, are trying to attract cloud computing data centers.• Energy efficiency in cloud computing can result from energy-aware scheduling and server consolidation.• However, in the case of distributed clouds over data centers with different source of energies including renewable source of energies, a small compromise on energy consumption reduction could result in high carbon footprint reduction.
Abuse:• As with privately purchased hardware, customers can purchase the services of cloud computing for nefarious purposes.• This includes password cracking and launching attacks using the purchased services.• In 2009, a banking Trojan illegally used the popular Amazon service as a command and control channel that issued software updates and malicious instructions to PCs that were infected by the malware