OVERCOMING THE CHALLENGES OF TODAY S CLOUD REALITY

Transcription

1 OVERCOMING THE CHALLENGES OF TODAY S CLOUD REALITY May 2011 Rev. B 05/11

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3 SPIRENT 1325 Borregas Avenue Sunnyvale, CA USA Web: AMERICAS SPIRENT EUROPE AND THE MIDDLE EAST +44 (0) ASIA AND THE PACIFIC Spirent. All Rights Reserved. All of the company names and/or brand names and/or product names referred to in this document, in particular, the name Spirent and its logo device, are either registered trademarks or trademarks of Spirent plc and its subsidiaries, pending registration in accordance with relevant national laws. All other registered trademarks or trademarks are the property of their respective owners. The information contained in this document is subject to change without notice and does not represent a commitment on the part of Spirent. The information in this document is believed to be accurate and reliable; however, Spirent assumes no responsibility or liability for any errors or inaccuracies that may appear in the document.

4 Main Title Style Subtitle Style CONTENTS Executive Summary Background Introduction The State of Cloud Computing Moving Ahead Within Today s Cloud Reality Overcoming the Challenges Conclusion SPIRENT WHITE PAPER i

5 EXECUTIVE SUMMARY Cloud computing is one of the most hyped approaches to IT today. While it has great potential for cost savings, efficiency and agility, it also introduces some new challenges. Market adoption models like Crossing the Chasm and the Hype Cycle indicate cloud computing is gaining momentum and seeing increased adoption. They also suggest that more organizations will encounter challenges and even failures in deploying cloud computing environments. The reality of Cloud today is a combination of high potential and hidden surprises. Major cloud service interruptions are likely to make headlines, particularly in this stage of cloud computing adoption. One notable service interruption began on April 21st, 2011 when Amazon Web Services (AWS) experienced a network event that resulted in a cascade of issues that impacted customers for several days. Reports from AWS indicated network congestion caused storage volumes to be re-mirrored leading to even more network congestion as well as a shortage of storage resources. Could this have been prevented? In order to improve the odds of success in deploying an Infrastructure as a Service (IaaS) environment, leaders of enterprise IT and service provider organizations must: Be familiar with the unique challenges of cloud computing Confirm that the right technical and business questions are asked Ensure that these questions are answered based on hard data Proper testing and validation of cloud computing environments is not easy. Leaders of organizations that are building and operating cloud environments must make certain their teams have the resources needed for success. These include: 1. Performance, availability, security, scalability (PASS) testing methodologies with detailed procedures and test cases 2. Test equipment that supports the latest networking specifications 3. Automated tools designed for cloud testing Together, these resources can be used to help design, build and validate clouds that meet the performance, availability, security and scalability requirements of customers. After all, no one wants to be responsible for a cloud failure. 1 SPIRENT WHITE PAPER

6 BACKGROUND Cloud computing is one of the most popular topics in the IT world today. Yet, there is still confusion on what it really means. There are at least a couple of good explanations for this. First, vendors and service providers continue to introduce competing definitions, often emphasizing the unique strengths of their own offerings. Second, media organizations tend to over-simplify definitions in hopes of making cloud computing understandable to the masses. Unfortunately, these approaches generate more confusion than clarity. What is needed is an intelligent, vendor neutral explanation of cloud computing that maintains the substance, breadth and nuances of its meaning. The Information Technology Laboratory of the National Institute of Standards (NIST) has done much of that with the following high level definition: Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. The NIST definition goes on to cover some other important elements of cloud computing by defining three related service models: Software as a Service (SaaS) - Applications run on a cloud infrastructure and are accessible from various client devices, typically via a web browser. Platform as a Service (PaaS) - Application development occurs in a cloud-based development platform and typically enables creation of web-enabled applications. Infrastructure as a Service (IaaS) - Infrastructure components including servers, storage and networks are available on demand through network connection. Many of the challenges in today s cloud reality are best explained at the Infrastructure as a Service (IaaS) layer and that is where the remainder of this white paper will focus. Since some form of Infrastructure as a Service (IaaS) is often used as a foundation for PaaS and SaaS environments, the issues that will be discussed still apply to most cloud computing environments. SPIRENT WHITE PAPER 2

7 INTRODUCTION Leaders across the IT industry are seeking the benefits of cloud computing. Enterprise IT organizations are building private clouds while service provider organizations are building public clouds. Enterprise IT organizations are seeking benefits that include efficiency, cost savings, agility and control. Service provider organizations are looking to cloud services for new sources of revenue and competitive advantage, as well as increased efficiency. Cloud computing seems to be the answer for everything. Don t Ignore the Challenges Of course cloud computing is not a silver bullet that solves every problem faced by IT. Leaders of enterprise IT and service provider organizations are still responsible for meeting the needs of all their stakeholders including...the harsh reality [is] that cloud computing introduces new challenges of its own. customers, users, business organization, investors. They must deliver on service level agreements (SLA) and quality of service (QoS) / quality of experience (QoE) objectives. They must ensure security, performance and reliability. They must also face the harsh reality that cloud computing introduces new challenges of its own. Public and private Infrastructure as a Service (IaaS) clouds both create similar challenges. Intensive utilization of infrastructure resources pushes existing technology to its limits. Granular resource sharing introduces security threats to multiple systems and users at the same time rather than one by one. Rapid changes in consumption levels drive increased competition for resources. Movement of applications adds complexity to troubleshooting. All these challenges can dramatically impact the performance, availability, security and scale of IT services. Those responsible for building and operating Infrastructure as a Service (IaaS) clouds must understand not only each new challenge, but also what can be done to overcome them. 3 SPIRENT WHITE PAPER

8 THE STATE OF CLOUD COMPUTING Most would agree that cloud computing has been overhyped for several years. Yet cloud is real, evidenced by increasing numbers of private cloud deployments and growing adoption rates for public cloud services. Two well known models for understanding technology markets provide additional insight to the current state of cloud computing. Crossing the Chasm The Crossing the Chasm model was introduced and popularized by bestselling author and consultant Geoffrey Moore. It begins with the idea that new technologies are first purchased by a group called early adopters. They are willing to endure the problems associated with fundamentally new products and services. Then, for the technology to reach mainstream adoption, a Chasm must be crossed. The Chasm is a figurative reference to technologies that fail to meet the needs of the majority of target buyers. Offerings that fail to cross the Chasm are destined to serve small markets or simply fail. Infrastructure as a Service (IaaS) is currently moving from the early adopter phase to the early majority phase in the Chasm model. In other words, Infrastructure as a Service (IaaS) is in the process of crossing the Chasm. The good news is that this indicates Infrastructure as a Service (IaaS) is proving to be valuable and is gaining traction. The bad news is that there is still a lot of variation in how clouds are built and few reference models for building clouds properly. This means, unfortunately, that some clouds will succeed while others will fail. Hype Cycle The Hype Cycle was developed by Gartner, a leading IT research and advisory company. It suggests that new technologies rapidly gain awareness and just as quickly become over-hyped. When a technology achieves it utmost hype, it has reached what the model calls the peak of inflated expectations. While new technologies may have long term potential in line with the hype, they must first pass through what is called the trough of disillusionment. In this stage, which begins after the peak of hype is reached, the realities and challenges associated with the new technology become apparent and opinions become overly negative. According to Gartner, the overall notion of cloud computing was hitting the peak of inflated expectations in It is now moving through the trough of disillusionment. As with the chasm model, this stage suggests good news and bad news. Once again, there is clear value to be found in cloud computing. However, an increasing number of public failures and other issues will cause backlash. Rather than just hype, there will also be condemnation and criticism SPIRENT WHITE PAPER 4

9 Proceed with Caution While both models indicate some concerns, there are also risks associated with not moving ahead. For instance, relying on old approaches or technology for too long can lead to competitive gaps or stagnation. The expected rewards from cloud adoption and the risks of not moving forward indicate continued market growth. Mainstream adoption is on its way. However, given the current state of cloud computing, IT leaders should proceed with caution MOVING AHEAD WITHIN TODAY S CLOUD REALITY As mentioned, enterprise IT organizations and service providers have some slightly different reasons for moving to cloud. Similarly, the benefits they seek for themselves and for their users are also slightly different. Whether you are building and operating a private cloud or a public cloud, it is important to clarify the expected benefits for users and customers. Business Drivers and Benefits Service Providers For service providers, the addition of cloud computing services may be done for several different reasons. Managed service providers (MSP) use Infrastructure as a Service (IaaS) clouds to increase efficiency, lower costs and increase profits. MSPs often provide fixed price contracts to their customers, so increases in efficiency during the life of a given contract flow straight to their bottom line. Hosting providers are adding Infrastructure as a Service (IaaS) in response to new competitors that are focused exclusively cloud services. Communications service providers (CSP) are leveraging existing investments in network infrastructure to gain a new source of revenue. Regardless of why service providers build clouds, they must deliver value to their customers. By supporting new business models such as pay-per-use, service providers let their customers shift capital investments to expenses. By pooling large amounts of resources, service providers give customers access to what appears to be an unlimited amount of IT capacity. Service providers also take responsibility for space, power, cooling and certain IT management tasks, performing those activities more efficiently than individual customers could on their own. 5 SPIRENT WHITE PAPER

10 Enterprise IT Many enterprise Infrastructure as a Service (IaaS) cloud deployments are initially designed to save money. Physical servers have been under-utilized, typically just seeing 10-15% average CPU consumption rates. This has driven IT organizations to consolidate servers using virtualization, bringing average CPU consumption closer to 40% or even 50% utilization. Cloud computing is now seen as the next step in efficiency and can produce utilization levels as high as 75% or more. Users of enterprise IT clouds enjoy many of the benefits of public clouds and cite some additional advantages. Accurate or not, some organizations simply feel security is greater when infrastructure, applications and data are located on premise. When digging deeper into this perspective, the underlying concern often turns out to be a desire for control rather than specific risks. In any case, private clouds are a viable alternative. They also serve as the foundation for hybrid clouds where certain applications and data always remain on premise and other applications may access public resources in times of peak demand. The Benefit of Agility Agility is sometimes a surprise benefit. IT leaders may initially focus on the financial benefits of cloud computing. Then, once users are taking advantage of the cloud services, agility is often listed as the top outcome. Both public and private clouds let their users become far more agile. For example, users get selfservice access to IT resources the moment they are needed. This eliminates a long series of delays involving purchase orders, approvals, shipment and setup. Without these delays, users can more quickly adapt to changes in demand or in the competitive environment. Infrastructure as a Service (IaaS) is not just Server Virtualization Cloud computing provides some obvious benefits. Still, challenges remain. One source of problems stems from equating Infrastructure as a Service (IaaS) with server virtualization. Any organization can deploy virtualized servers. Enterprises have done plenty of this through server consolidation. Similarly, hosting providers have offered virtual private servers (VPS) for years. However, it is important to realize that Infrastructure as a Service (IaaS) is not simply server virtualization. Infrastructure as a Service (IaaS) adds characteristics such as on-demand selfservice, allowing users to provision resources by leveraging automation rather than involving administrators. Further, large amounts of resources are pooled together and shared in Infrastructure as a Service (IaaS) environments. Resource pooling enables rapid elasticity or the ability to quickly gain access to additional resources and just as quickly return them for use by others. Infrastructure as a Service (IaaS) clouds may also support application awareness and dynamic resource optimization. This is where building and operating cloud environments becomes more difficult. SPIRENT WHITE PAPER 6

11 High-level Challenges Increased resource sharing creates a number of challenges. When done properly, it means higher utilization and greater efficiency. When done poorly it leads to resource contention and failed SLAs. Resource sharing also requires diligent enforcement of security. Applications using the same server or database must not have access to data from other applications. Cloud providers must also ensure that noisy neighbors applications attempting to consume more than their fair share of resources do not impact other applications. Cloud providers have plenty of other challenges to consider. Infrastructure as a Service (IaaS) environments tend to have an API which provides programmatic control over resources. This can lead to extremely fast changes in resource consumption as well as rapid modifications to infrastructure configurations. Cloud providers must have intelligence and automation to move virtual machines (VM) from one server to another in response to changes in demand and resource utilization. All this must be handled transparently to the applications that are running on highly utilized servers with densely packed VMs. Cloud environments tend to have a greater reliance on virtualized resources with server virtualization as the most obvious. Another example is storage virtualization through SANs which enables VMs to run on any server. Network virtualization including virtual switches, load balancers and firewalls is also predominant. Even applications themselves are becoming more virtualized. For example, as the web tier or application tier encounters more demand, elastic applications can self-provision additional resources to maintain SLA commitments. Of course virtual components have different performance and scalability attributes which adds a number of design challenges. Technology Decisions At some point, the right technology decisions must be made in order to overcome the challenges and deliver the value promised by cloud computing. Not surprisingly, architecture, design and implementation decisions have a huge impact on how cloud environments behave. This includes performance, availability, scale and security, also known as PASS. Making the right technical decisions requires many complex questions to be answered accurately: How many 10Gbps connections can my servers potentially saturate? Is 10Gbps or 40Gbps Ethernet the best choice? What about Fibre Channel over Ethernet (FCoE) for a converged LAN / SAN? Is a non-blocking SAN required or can it be over-provisioned? Does one vendor or another have a better core network fabric solution? 7 SPIRENT WHITE PAPER

12 Should low-end 8-core servers or high-end 20-core servers be used? Which configuration supports more VMs or generates the most revenue? How well does a particular hypervisor / server combination work? What does a shared virtual switch mean to server performance? How does the security of a software appliance compare to a hardware device? Are security profiles properly moving along with the VMs? Depending on the requirements of a given cloud environment, there may be many more considerations. These technical questions raise an even more important question for IT leaders. Does your team have the appropriate tools for answering all these questions? More Questions for IT Leaders While architects and other senior technical staff must ultimately answer the technical questions, IT managers, including the CIO, remain responsible for the overall outcome of cloud implementations. IT managers are accountable for ensuring good answers to all of these questions: Has the team come up with the right architecture? Are we using the right components? Will we meet performance and SLA requirements once it is built? What will happen during periods of peak demand? How will we determine the underlying cause when something goes wrong? IT managers do not want to become victims of the Chasm or the trough of disillusionment. They want to realize the benefits of cloud computing and reap the accompanying rewards. To do this, they must ensure that the answers to all of these important questions are based on hard data. SPIRENT WHITE PAPER 8

13 OVERCOMING THE CHALLENGES The hard data needed to ensure success comes from PASS testing which includes assessments of performance, availability, security and scalability. PASS testing is done on infrastructure components such as servers, network elements, storage devices and virtual appliances. It is also performed at the system level to ensure the assembled components still perform correctly when used together by applications. PASS Testing for Cloud Computing Environments As discussed, cloud computing environments are different than traditional datacenter environments and create an array of new challenges. Some of the challenges show up in PASS testing Performance Measuring the performance of a cloud computing environment is not sufficiently done with one or even a dozen tests. Many hundreds of individual measurements including throughput and latency of virtual switches, virtual appliances, converged network adapters (CNA), top of rack switches, datacenter cross-connects and various applications are required to fully characterize cloud performance. Then, a good portion of these tests must be repeated under a variety of different conditions. What happens, for instance, when server and storage traffic are simultaneously reaching peaks? Will virtual switches within hypervisors keep up with high network traffic when applications are competing for the same CPU? Availability White-Papers/Broadband/ PAB/EANTC_CloudComputing_Whitepaper.aspx Availability in Infrastructure as a Service (IaaS) clouds is enhanced by capabilities such as live migration, dynamic resource scheduling and automatic restarts. Yet these same features have the potential to create problems of their own. Since live migrations happen when load on the infrastructure is high, they place additional demand on resources that are already scarce. The net result may actually be further performance or availability degradation. PASS testing must be used to measure VM downtime during live migrations. Testing should include moving VMs, along with their running applications, from heavily loaded servers. It should also include measuring failover time for dozens of simultaneous high availability restarts due to a physical server failure. 9 SPIRENT WHITE PAPER

14 Security Multi-tier applications consisting of web, application and database tiers produce network traffic multiple times during each transaction. Since security is required at every layer, including the hypervisor, virtual and physical appliances may impact application performance. Attempts at tuning performance may result in accidental vulnerabilities. With cloud computing, security must address targeted attacks, viruses and other risks while maintaining the performance, availability and scalability for all cloud tenants. PASS testing helps uncover vulnerabilities and can also be used to determine the right mix of physical and virtual security appliances. This is an important consideration since every CPU cycle spent checking security cannot be sold to customers. Scalability Cloud environments tend to be quite large, from hundreds of servers to tens of thousands. Consider a cloud infrastructure with a thousand servers. It will have many thousands of cores supporting tens of thousands of VMs. This type of density leads to a huge increase in network traffic. Scalability testing must not only validate that tens of thousands of VMs can operate simultaneously, it must confirm they can do so with peak traffic rates across all layers of the network. Tools and Procedures Homegrown tools and scripts are insufficient for testing and validating complex systems such as cloud computing environments. In fact, testing in general typically requires automated test tools that are just as complex and powerful as the system under test. The selection of commercial testing products must be done carefully. Cloud networks take advantage of the newest equipment, built with the latest network specifications. Be sure to select testing products that are continually updated to support leading edge cloud networks. Test cases and procedures must also be properly developed in order to accomplish the desired results. The Spirent Journal of PASS Test Methodologies by Spirent Communications is an element of the Spirent test ecosystem that defines and documents the most critical PASS test cases. It includes the Spirent Catalogue of Test Methodologies which are intended to help development engineers and product verification engineers rapidly develop and test complex scenarios. Sections like Testing Cloud Application and Security Services help clarify what should be tested and provide step-by-step procedures for doing so. SPIRENT WHITE PAPER 10

15 Using PASS test methodologies along with automated tools and test cases greatly improves the odds of success for any cloud environment. Hard data from PASS testing should be gathered and used during the architecture and design phase, deployment phase and during the ongoing operation of the cloud environment. A faulty assumption on virtual switch performance should not be the cause of a bad architecture. When problems do arise in an operational cloud, a single mis-configured box must be quickly found among thousands and fixed before widespread SLA violations occur. CONCLUSION Cloud computing has great potential for cost savings, efficiency, agility and more. These compelling benefits are driving higher adoption rates for public cloud services and increased deployments of private clouds. Models like Crossing the Chasm and the Hype Cycle indicate cloud computing is in the process of moving toward mainstream adoption. They also suggest that more organizations will encounter challenges and even failures in deploying cloud computing environments. The reality of cloud today is a combination of high potential and hidden surprises. In order to improve the odds of success in deploying an IaaS environment, leaders of enterprise IT and service provider organizations must be familiar with the unique challenges of cloud computing. They must confirm that the right technical and business questions are asked. They must also make certain that these questions are properly answered, based on hard data derived from testing and validation. Proper testing and validation of cloud computing environments is not easy. Leaders of organizations that are building and operating cloud environments must ensure their teams have the resources needed for success. The three key points to remember are: 1. PASS testing methodologies with detailed procedures and test cases 2. Test equipment that supports the latest networking specifications 3. Automated tools designed for cloud testing 11 SPIRENT WHITE PAPER

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