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Presented by: Prof Mark Baker
ACET, University of Reading Tel: +44 118 378 8615
E-mail: [email protected] Web: http://acet.rdg.ac.uk/~mab
An overview of Cloud Computing and its Services
16th September, 09
OpenCirrus
Outline• Origins of Clouds,• Cloud definition and characteristics,• Service and deployment models,• Architecture,• Taxonomy and Characteristics,• Cloud Hyperbola,• Issues that need to be Understood!,• Cloud Security Risks,• Virtualization,• Green IT,• Advantages/disadvantages/issues/problems,• The Future.
16th September, 09
Origins of Clouds• The idea of an "intergalactic computer network"
was introduced in the sixties by J.C.R. Licklider, who was responsible for enabling the development of ARPANET (Advanced Research Projects Agency Network) in 1969:– His vision was for everyone on the globe to be inter-
connected and accessing programs and data at any site, from anywhere.
• Other experts attribute the cloud concept to the computer scientist John McCarthy, who proposed the idea of computation being delivered as a public utility, similar to the service bureaus that date back to the sixties.
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Origins of Clouds• Since the sixties, cloud computing has developed
along a number of lines, with Web 2.0 being the most recent evolution!
• Since the Internet started to offer significant bandwidth in the 1990s, cloud computing for the masses has been something of a late developer.
• The firm Salesforce.com in 1999, which pioneered the concept of delivering enterprise applications via a simple web site:– The services provided paved the way for both specialist
and mainstream software firms to deliver applications over the Internet.
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Origins of Clouds• The next development was Amazon Web Services
in 2002that provided cloud-based services including storage, computation and even human intelligence through the Amazon Mechanical Turk:– https://www.mturk.com/mturk/welcome
• In 2006, Amazon launched its Elastic Compute cloud (EC2) as a commercial web service that allowed companies and individuals to rent computers on which to run their own computer applications.
• Amazon EC2/S3 was the first widely accessible cloud computing infrastructure service.
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Cloud-based Systems
• Users purchase an entire solution:– salesforce.com
• Users interface with resources through programming interface:– Google AppEngine, and AppScale
• Users access resources through service interface: – Microsoft Azure
• Users provision entire infrastructure:– Amazon EC2, OpenNebula, Nimbus, Enomalism,
Eucalyptus, Open Cirrus, GoGrid…
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A Definition of Cloud Computing• Cloud computing is a model for enabling
convenient, on-demand network access to a shared pool of configurable resources:– e.g. networks, servers, storage, applications, and
services.
• These resources can be provisioned and released with minimal management effort or service provider interaction.
• A cloud model promotes availability and is composed of five essential characteristics, three service models, and deployment models.
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Cloud Characteristics• On-demand self-service:
– A consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service’s provider.
• Ubiquitous network access:– Services are available over the network and accessed
through standard mechanisms that promote the use of heterogeneous platforms, such as mobile phones, laptops, and PDAs.
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Cloud Characteristics• Resource pooling:
– The computing resources are pooled using a homogenous infrastructure to serve consumers using a multi-functional model, with different physical/virtual resources dynamically assigned and reassigned according to consumer demand.
– There is a sense of location independence as the customer generally has no control or knowledge over the exact location of the provided resources but may be able to specify a location at a higher level of abstraction (e.g., country, state, or datacenter).
– Examples of resources include storage, processing, memory, network bandwidth, and virtual machines.
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Cloud Characteristics• Elasticity:
– Capabilities can be quickly and elastically provisioned, and in some cases automatically.
– This allows a scale up /down for resource use. – To the consumer, the capabilities available for
provisioning often appear to be infinite and can be purchased in any quantity at any time.
• Measured service:– Cloud systems automatically control and optimise the
resources used, by leveraging a metering capability at some level of abstraction for the type of service, e.g., storage, processing, bandwidth, and active user accounts.
– Resources use can be monitored, controlled, and reported providing transparency for both the provider and consumer of the utilised service.
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Cloud Service Models
• Cloud Software as a Service (SaaS): – The capability provided to the
consumer is to use the provider’s applications running on a cloud infrastructure, which is accessible from various client devices, such as a Web browser.
– The consumer does not manage or control the underlying cloud infrastructure, or even individual application capabilities, with the possible exception of initial user-specific application configuration settings.
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Cloud Service Models• Cloud Platform as a
Service (PaaS):– The consumer deploys their
the applications onto the cloud using programming languages and tools supported by the provider, such as Java, python, .Net.
– The consumer does not manage/control the underlying cloud infrastructure, but has control over the deployed applications and possibly application hosting environment configurations.
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Cloud Service Models• Cloud Infrastructure as a Service
(IaaS):– The capability is provided to the
consumer, who can use processing, storage, networks, and resources.
– The consumer is able to deploy and run arbitrary software, which can include an operating systems and applications.
– The consumer does not manage or control the underlying cloud infrastructure; they have control over operating systems, storage, deployed applications, and possibly select networking components, e.g., firewalls, load balancers.
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Different Cloud Computing Layers
Application Service(SaaS)
Application Platform
Server Platform
Storage Platform Amazon S3, Dell, Apple, ...
3Tera, EC2, SliceHost, GoGrid, RightScale, Linode
Google App Engine, Mosso,Force.com, Engine Yard,Facebook, Heroku, AWS
MS Live/ExchangeLabs, IBM, Google Apps; Salesforce.comQuicken Online, Zoho, Cisco
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Cloud Service Layers
Cloud Infrastructure Services (IaaS)
Cloud Platform Services (PaaS)
Cloud End-User Services (SaaS)
Physical Infrastructure
Service Users
Clo
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Clo
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Serv
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Pro
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Serv
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Pro
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Services
Application
Development
Platform
Storage
Hosting
Cloud Computing Service LayersDescriptionServices – Complete business services such as PayPal, OpenID, OAuth, Google Maps, Alexa
Services
Application
Focused
Infrastructure
Focused
Application – Cloud based software that eliminates the need for local installation such as Google Apps, Microsoft Online
Storage – Data storage or cloud based NAS such as CTERA, iDisk, CloudNAS
Development – Software development platforms used to build custom cloud based applications (PAAS & SAAS) such as SalesForcePlatform – Cloud based platforms, typically provided using virtualization, such as Amazon ECC, Sun Grid
Hosting – Physical data centers such as those run by IBM, HP, NaviSite, etc.
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Deployment Models• Private cloud:
– The cloud infrastructure is operated solely by an organisation.
• Community cloud:– The cloud infrastructure is shared by several organisations
and it supports a specific community that has shared concerns
• Public cloud:– The cloud infrastructure is made available to the general
public or a large industry group and is owned, potentially, by an organisation selling cloud services.
• Hybrid cloud:– The cloud infrastructure is a composition of two or more
clouds (e.g. private, community, or public) that remain unique entities but are bound together by standardised or proprietary technologies that enables data and application portability.
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Cloud Characteristics• Large scale,• Virtualization,• Non-stop computing,• Free software,• Geographic distribution,• Service oriented architecture,• Autonomic computing,• Security technologies.
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Cloud Characteristics• Large Scale:
– Cloud implementations, regardless of the deployment model, tend to be as large in order to take advantage of economies of scale:
• Large deployments can often be located next to cheap power and real estate to lower costs!
– They often take advantage of bulk commodity hardware purchases and streamlined data-centre.
– To improve effectiveness, large cloud deployments may be located near a high speed Internet hubs..
• Virtualization:– This is critical, it provides the essential characteristics of
location independent resource pooling and rapid elasticity. – Virtualization enables data centres to increase their server
utilisation from a typical 10% to an ideal 80% that can produce significant cost savings.
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Cloud Characteristics• Non-stop computing:
– Clouds enables the characteristics of non-stop computing. – This means that applications can take advantage of the
cloud-based distributed software.– The hardware enables an application to remain active at all
times even through upgrades.
• Free Software:– The scale of many clouds combined with the need for
many software licenses encourages the use of free software in the development of clouds.
– By free software we refer to Open source products that are potentially free to the cloud developer, otherwise the software is cheaply licensed.
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Cloud Characteristics• Geographic Distribution:
– Cloud systems that are built on the concept of resource pooling may not have separate backup sites!
– Cloud providers rely on unused cloud capacity to provide disaster recovery capabilities.
– The providers not only need significant unused capacity, but must have their resource pool geographically distributed so that a single data centre disaster will not cause an outage or overcapacity situation.
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Cloud Characteristics• Service Oriented Architecture:
– “Cloud software takes full advantage of this paradigm with a focus on statelessness, low coupling, modularity, and semantic interoperability.”
– An important characteristic for cloud applications so that they use the location independent resource pool and provide elasticity capabilities.
– Clouds can run applications that do not have this characteristic, but such applications will be isolated workloads so the provider gives reliability and scalability.
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Cloud Characteristics• Autonomic Computing:
– Cloud implementations often have automated systems to enable their management and security.
– This enables them to be large, sophisticated, and be cost effective.
– IBM definition - autonomic computing has four properties: self-healing, self-configuration, self-optimization, and self-protection.
– Clouds may exhibit all of these properties. – These properties do not commonly exist in advanced forms
that are not always available using traditional computing models.
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Cloud Characteristics• Security Technologies.
– Cloud implementations should contain advanced security technologies.
– The resource pooled nature, enables providers to focus all their security resources on potentially securing the cloud architecture.
– At the same time, the automation capabilities within a cloud combined with the large focused security resources should result in advanced security capabilities.
– These capabilities are necessary because the multi-functional nature of clouds increases the threat exposure compared to traditional computing models.
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Increasing use of Clouds• Cloud computing is increasingly being used for
what was known as “on-demand” and “utility computing”.
• The services provided, the APIs and the applications that can be hosted by these Cloud providers have superseded the use of the Grid, and are increasingly becoming popular with users.
• There are obviously two sides to the services that are provided by Cloud providers: those that are supplied by commercial entities, such as Amazon and Google, as well as those that are open-source systems, such as provided by OpenCirrus and Eucalyptus.
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Cloud Hyperbola!• Unfortunately, much of the information and news
about Cloud-based systems are related to publicity and hyperbola.
• What is needed is a fair and unbiased review of these systems so that people who want to use Cloud-based systems know what they get!
• The consumers needs to understand the architecture, the services provided, the protocols used, security implications, and applications that can be executed, as well as factors such inter-operability, performance and scalability.
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Cloud Security Risks• Trusting the service provider’s security model:
– The data owner bears ultimate responsibility regardless!
• Inability to respond to audit findings:– Cloud customers cannot force security remediation on
service providers without contractual guarantees.
• Obtaining support for investigations:– Airing dirty laundry and notifications for security events.
• Loss of physical control:– In a virtual world, do you know where your data is
processed and stored?
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Potential Security Issues1. Privileged user access:
– Sensitive data provides an inherent level of risk, because out sourced services by pass the "physical, logical and personnel controls” exert over in-house resources.
– You need as much information as you can about the people who remotely manage your data.
2. Regulatory compliance:– Consumers are responsible for the security and integrity
of their own data, even when it is held by a service provider.
– Service providers should be subject to external audits and security certifications.
– Providers who refuse to undergo this scrutiny level are "signaling that customers can only use them for the most trivial functions”.
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Potential Security Issues3. Data location:
– When using a cloud, you will not know exactly where your data is hosted - it could be in stored in many countries
– Need to know if the providers will commit to storing and processing data in specific jurisdictions, and whether they will make a contractual commitment to obey local privacy requirements on behalf of their customers.
3. Data segregation:– Data in the cloud is typically in a shared environment
alongside data from other customers. – The cloud provider should provide evidence that
encryption schemes were designed and tested by specialists.
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Potential Security Issues5. Recovery:
– Even if you do not know where your data is, a provider should tell you what will happen to your data in case of a failure!
– Any provider that does not replicate the data and application infrastructure across multiple sites is vulnerable to a total disaster.
5. Investigative support:– Need to investigate illegal activities may be impossible in
clouds, – The services are difficult to investigate, because logging and
data for multiple customers may be co-located and may also be spread across an ever-changing set of hosts and data centres.
– Need a contractual commitment to support specific information.
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Potential Security Issues7. Long-term viability.
– Ideally, your cloud provider will never go broke or get acquired and swallowed up by a larger company.
– You need to be sure your data will remain available even after such an event.
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Virtualization• Virtualization disconnects software from a specific
piece of dedicated hardware. • Physical resources such as servers and storage
devices appear as single logical resources, and virtualization software determines how many of these physical devices to employ.
• This can result in increased utilisation of computing assets, lowered power and cooling costs, easier lifecycle management, and less sophisticated backup/disaster recovery.
• Although many associate the word "virtualization" with just server virtualization, there are in fact many opportunities within the software stack to beneficially introduce virtualization concepts.
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Virtualization• Various system currently offer solutions to
address various areas: server, storage, and application/desktop virtualization.
• Permits a “guest” operating system to be executed as a process on a “host” operating system.
• Achievable through several mechanisms:– Operating system containers,– Traditional virtual machine monitors,– Para-virtualization systems,– Hardware-assisted virtualization.
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Virtualization• Virtual workspaces:
– An abstraction of an execution environment that can be made dynamically available to authorised clients by using well-defined protocols,
– Resource quota (e.g. CPU, memory share),– Software configuration (e.g. O/S, provided services).
• Implement on Virtual Machines (VMs): – Abstraction of a physical host machine,– Hypervisor intercepts and emulates instructions from
VMs, and allows management of VMs,– VMWare, Xen, etc.
• Provide infrastructure API:– Plug-ins to hardware/support structures
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Hardware
OS
App App App
Hypervisor
OS OS
Virtualized Stack
Virtual Machines• VM technology allows multiple virtual machines to
run on a single physical machine.
Hardware
Virtual Machine Monitor (VMM) / Hypervisor
Guest OS(Linux)
Guest OS(NetBSD)
Guest OS(Windows)
VM VM VM
AppApp AppAppAppXen
VMWare
UML
Denali
etc.
Performance: Para-virtualization (e.g. Xen) is very close to raw physical performance!
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Green Computing
• Why?– Computer energy is often wasteful:
• Leaving the computer on when not in use (CPU and fan consume power, screen savers consume power).
– Pollution:• Manufacturing techniques,• Packaging,• Disposal of computers and components.
– Toxicity:• Toxic chemicals used in the manufacturing
of computers and components which can enter the food chain and water!
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Energy Use of PCs• CPU uses 120 Watts.• Cathode Ray Tube (CRT) uses 150 Watts:
– 8 hours of usage, 5 days a week = 562 Kwatts:• If the computer is left on all the time without proper power saver
modes, this can lead to 1,600 Kwatts.
– For a large institution, say a university of 40,000 students and faculty, the power bill for just computers can come to £1.5 million / year
• Energy use comes from:– Electrical current to run the CPU, motherboard, and
memory,– Running the fan and spinning the disk(s),– Monitors - CRTs consume more power than any other
computer component.
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Reducing Energy Consumption• Turn off the computer when not in use, even if just
for an hour.• Turn off the monitor when not in use (as opposed to
running a screen saver).• Use power saver mode:
– In power saver mode, the top item is not necessary, but screen savers use as much electricity as any normal processing, and the screen saver is not necessary on a flat panel display.
• Use hardware/software with the Energy Star label– Energy Star is a “seal of approval” by the Energy Star
organization of the government (the EPA)
• Use LCDs instead of CRTs as they are more power efficient.
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Green IT and Virtualization• Energy saving benefits:
– VM allows the possibility to control the applications.– Lower management costs,– Significantly lower replacement costs,– More flexible and responsive to requests,– Additional Disaster Recovery Capabilities.
• Reduce the number of systems consuming power!• Improve average utilisation, potentially more
efficient than on bare-metal!– Many HPC applications are only 15 – 20% efficient, VM
provide the opportunity to be around 75 – 80%.– Need further evidence and proof still.
• Improved management capabilities across the board.
Cloud Use• Popular cloud apps:
• Facebook: 64K UW users; now big in classes,• Google Gmail, Docs, Calendar,• Windows Live (esp. Messenger),• Doodle (meeting scheduler),• Blackboard online used by Biz School & UW-
Bothell.• Platform services
• Amazon EC2/S3,• Slicehost.
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Basic Cloud Characteristics• The “no-need-to-know” in terms of the underlying
details of infrastructure, applications interface with the infrastructure via the APIs.
• The “flexibility and elasticity” allows these systems to scale up and down at will – utilising the resources of all kinds (CPU, storage, server capacity, load balancing, and databases).
• The “pay as much as used and needed” type of utility computing and the “always on!, anywhere and any place” type of network-based computing.
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What is the purpose and benefits?• Cloud computing enables companies and
applications, which are system infrastructure dependent, to be infrastructure-less.
• By using the Cloud infrastructure on “pay as used and on demand”, all of us can save in capital and operational investment!
• Clients can:– Put their data on the platform instead of on their own
desktop PCs and/or on their own servers.– They can put their applications on the cloud and use
the servers within the cloud to do processing and data manipulations etc.
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Opportunities and Challenges
• The use of the cloud provides a number of opportunities: – It enables services to be used without any understanding of
their infrastructure.– Cloud computing works using economies of scale:
• It potentially lowers the outlay expense for start up companies, as they would no longer need to buy their own software or servers.
• Cost would be by on-demand pricing. • Vendors and Service providers claim costs by establishing an
ongoing revenue stream.
– Data and services are stored remotely but accessible from “anywhere”.
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Cloud-Sourcing• Why is it becoming a Big Deal:
– Using high-scale/low-cost providers,– Any time/place access via Web browser,– Rapid scalability; incremental cost and load
sharing,– Can forget need to focus on local IT.
• Concerns:– Performance, reliability, and SLAs,– Control of data, and service parameters,– Application features and choices,– Interaction between Cloud providers,– No standard API – mix of SOAP and REST!– Privacy, security, compliance, trust…
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Some Commercial Cloud Offerings
Problem: Commercial offerings are proprietary and usually not open for cloud systems research and development
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Advantages of Cloud Computing• Lower computer costs:
– You do not need a high-powered and high-priced computer to run cloud computing's web-based applications.
– When you are using web-based applications, your PC can be less expensive,
• Reduced software costs: – Instead of purchasing expensive software applications,
you can get most of what you need for free-ish!– Most cloud computing applications today, such as the
Google Docs suite, are totally free. – That is a lot better than paying $200+ for similar
Microsoft Office software - which alone may be justification for switching to cloud applications.
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Advantages of Cloud Computing• Instant software updates:
– Another advantage is that cloud computing is that you are no longer faced with choosing between obsolete software and high cost upgrades.
– When you access a web-based application, you get the latest version - without needing to pay for or download an upgrade.
• Unlimited storage capacity:– Cloud computing offers virtually limitless storage. – Your computer's current 200 Gbyte hard drive is small
compared to the hundreds of Pbytes available in the cloud. – Whatever you need to store, you can.
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Disadvantages of Cloud Computing• Requires a constant Internet connection:
– You need a decent Internet connection!– A dead Internet connection means no work and in areas
where Internet connections are few or inherently unreliable, this could be a deal-breaker.
– When you are offline, cloud computing simply does not work.
• Does not work well with low-speed connections: – Similarly, a low-speed Internet connection, such as that
found with dial-up services, makes cloud computing painful at best and often impossible.
– Web-based applications require a lot of bandwidth to download, as do large documents.
– In other words, cloud computing is not for the broadband-impaired!
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Disadvantages of Cloud Computing• Stored data might not be secure:
– With cloud computing, all your data is stored remotely. – Can un-authorised users gain access to your confidential
data? – Cloud providers say that data is secure, but it is too early
to be completely sure of that.
• Data can be lost:– Theoretically, data stored in the cloud is safe, but it
should be replicated across multiple systems. – But on the off chance that your data goes missing, you
have no physical or local backup. – Put simply, relying on the cloud puts you at risk if the
cloud lets you down.
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Disadvantages of Cloud Computing• HPC Systems:
– Not clear that you can run compute-intensive HPC applications that use MPI/OpenMP!
– Scheduling is important with this type of application – as you want all the VM to be co-located to minimise communication latency!
• General Concerns:– Each cloud systems uses different protocols and different
APIs… so it may not be possible to run applications between cloud based systems.
– Amazon has created its own DB system (not SQL 92), and workflow system (many popular workflow systems out there) – so your normal applications will have to be adapted to execute on these platforms.
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Issues that need to be Understood!• An architectural view of the systems and a good
understanding of the services that are provided, as well as the protocols that are used.
• Knowledge about capacity planning and resource allocation mechanisms.
• Security including the technologies, policies and mechanisms used, and issues related to the possession and ownership of data.
• The use of virtualization and the abilities to use legacy and new applications on these VMs.
• Potential use of fault-tolerance mechanisms to provide reliable applications – failure could be a disaster for ones applications!
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Issues that need to be Understood!• Knowledge about the distributed programming
abstractions that can be used, plus information about the types of applications executed, ranging from simple client/server through to sophisticated HPC applications: – Can these systems efficiently run MPI, OpenMP and threads?
• Information about application development and the potential for debugging and profiling on these systems.
• Scheduling is an important feature:– It is essential to ensure that applications are co-located
together to reduce latency and increase bandwidth.
• Monitoring and logging capabilities to help understand application performance, resource use, failures, faults bottlenecks and other potential problems + low overheads too!
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Issues that need to be Understood!• Service Level Agreements (SLAs) and Quality of
Service (QoS) agreements, are needed so that the resources reserved, provided and the services are assured.
• Need to create a range of benchmarks that can be used to help assess the performance and potential scalability of Cloud-based systems.
• Inter-operability needs to be assessed and addressed because it will be clear that users may want to execute their applications on or across multiple cloud systems.
• “Green IT” on clouds where applications and the infrastructure can be optimised to minimise energy consumption.
• Information about storage, information preservation and back-ups.
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The Future• Many of the activities grouped together under clouds
have already been happening and centralised computing activity is an increasing phenomena.
• Grid Computing is dying off fast – applications are more important than middleware!
• However, there are concerns that the mainstream adoption of using cloud-based system can potentially cause problems for users.
• Need in-depth reviews about the capabilities, components, security and implications of clouds.
• Many new open source systems appearing that you can install and run on your local cluster – should be able to run a variety of applications on these systems – not clear HPC applications are appropriate yet!
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