Welcome!

Cloud Expo Authors: JP Morgenthal, Craig Ferril, Michael Bushong, Peter Silva, Ed Featherston

Related Topics: Cloud Expo, SOA & WOA, Virtualization

Cloud Expo: Article

Challenges and Best Practices for Load Testing with the Cloud

Part 2: The key is to think of cloud testing as the delivery mechanism

In Part 1 I described how the cloud is revolutionizing load testing and the advantages it provides to ensure that your web applications perform well in production. We also looked at what capabilities you should seek out when selecting a load testing solution.

In Part 2, I will offer the limitations of a test strategy that relies solely on cloud-based testing, highlighting the need for a complementary internal load testing solution. I will also discuss several best practices for load testing in the cloud. Understanding how to apply the right tools and practices to make the most of the cloud is fundamental to cloud-based testing and vital to ultimately going live with total peace of mind.

The advantages to load testing with the cloud are clear, but internal testing still has its place in the overall test plan, particularly when testing from outside the firewall is not feasible. Internal testing also helps you to isolate effects that are due to your own application or infrastructure from those that are outside your firewall and potentially beyond your control.

The advantages to load testing with the cloud are clear, but internal testing still has its place in the overall test plan, particularly when testing from outside the firewall is not feasible. Internal testing also helps you to isolate effects that are due to your own application or infrastructure from those that are outside your firewall and potentially beyond your control.

Isolating Root Cause
When load testing uncovers a problem, the next step is identifying which layer in the delivery chain is causing the problem. You can use monitors to check performance metrics such has hits, average response time per request, and average bandwidth for each layer or piece of equipment in the chain. You can also employ application performance management (APM) solutions to identify bottlenecks in the code. These techniques work reasonably well when there is a single source for the performance slow-down.

When there are multiple problems, both inside and outside the firewall, it can be difficult to sort out the root causes because the symptoms are often commingled, making them difficult to isolate and resolve individually. For this reason it's important to have a cloud load testing solution that you can also apply within the firewall. You can then separate the problems that exist within the firewall from those caused by layers outside it. The ability to test a subset of the delivery chain in this way makes it much easier to find the root causes of performance problems.

Reproducing Tests
Often, you need to precisely measure the effect of changes made to the application code or settings. For example, you may need to determine the performance improvement that results from resolving a specific defect or evaluate performance for a range of cache sizes and other settings.

With cloud load testing, such precise measurements are difficult because of variations in Internet traffic and bandwidth availability at the data center level. Such variations can make it almost impossible to duplicate conditions from day to day or even within the same day.

As with isolating root causes, this situation also highlights the need for internal testing, in which you can better manage the conditions of the test, stabilize the testing environment, and take precise measurements to get more reliable performance metrics for comparison.

Conducting Small Scale Tests
Not all load testing requires hundreds of load generators. Even applications that anticipate many thousands of concurrent users are initially tested with a small population. These smaller scale tests require only a few machines may be easier and less expensive to conduct internally if the machines have already been purchased and are available for use. These tests can be carried out within the firewall to conduct tests that don't require a heavy load or the full delivery chain. To keep cloud expenses down, use available real machines when they can provide the information you need, and employ load testing with the cloud when necessary for larger scale, more realistic tests.

Testing Inside the Firewall
Of course, some testing use cases preclude the use of the cloud. If you're developing an enterprise web application that was not designed to be accessed from the Internet, then it's not a good idea to expose it outside the firewall solely for the purpose of load testing with the cloud. Likewise, if your pre-production environment is not set up to be accessed from the Internet, you'll want to have an internal testing solution that can be used within the firewall. Ideally, you want to use the same load testing solution for both internal testing and testing with the cloud, so that the scripts you developed for internal pre-production testing can be reused in production cloud-based testing. Using different tools for internal and cloud testing would not only require a rewrite of the scripts, it would also increase licensing and training costs.

Best Practices
The following best practices can help you maximize the advantages - and minimize the challenges - of load testing with the cloud.

Employ a Two-Stage Process
A two-stage process for load testing enables engineers to employ internal and cloud testing in the situations for which they are most effective and appropriate. In the first stage of the process you conduct internal tests with a medium load to quickly identify and resolve preliminary performance issues. Then increase the load incrementally with one or more load generators in the test lab. After the performance has been validated internally, proceed to the second stage, cloud-based load testing, for large scale tests that validate the entire delivery chain of the application.

This hybrid approach addresses the key challenges facing organizations that attempt to rely on testing from the cloud only:

  • It enables teams to isolate problems. The source of any performance issue identified in the first stage is clearly within the firewall (because no other systems are involved in the test). It's easier to pinpoint and fix internal problems when they are not being compounded by other issues that originate outside the firewall.
  • It enables earlier testing. With the two-stage process, you don't have to wait for the application to be deployed and accessible from the Internet to test it. You can test internally earlier in the application lifecycle when defects are easier and less expensive to fix.
  • It enables reproducible tests. With internal testing you have much more control over the environment, so you can precisely measure the effect of code or configuration changes on application performance.
  • It provides a better understanding of each major area of the delivery chain. You can compare the results of the same test scenario run internally and from the cloud to get a clearer picture of how the application server and network infrastructure contribute to overall response times.
  • It lowers costs. Cloud testing is based on a pay-per-use model. When you can test internally on hardware you already have, you can reduce the amount of testing that you need to perform from the cloud and cut costs.

Use Different Cloud Providers
There are several advantages to using multiple cloud providers. First, it helps you test from more geographical regions, which provides more realistic results that capture the effects of various third-party servers and content delivery networks. Second, it's more scalable. For exceptionally large scale tests, you can engage multiple providers simultaneously to bypass limitations that a single provider may place on bandwidth or the number of machines in use. Third, it enables you to detect potential network issues at the cloud provider level. If test results from virtually all providers show acceptable performance, but you're seeing significantly worse performance from machines on a particular provider, then you can safely conclude that there is a temporary problem with only that provider, not your application. Load testing solutions that are locked into a single provider limit the test engineer's ability to conduct realistic, reliable, large-scale tests.

Secure Your Data
In internal pre-production testing, the data used is often fake - not actual customer or user information. Further, you can be reasonably assured that any real data used is safe because testing is being conducted within the firewall. This is not the case when testing from the cloud on production data. You'll need to take steps to ensure that any accounts, scenarios, detailed error messages, and other sensitive data involved in your tests are secured.

Encrypt the communication between your controller and load generators. This helps secure data sent to the load generators during the test (including account information) as well as the data that is retrieved (including error messages). If possible, use SSL to secure the communication between the browser and the tested server. Last, ensure your load generators are secured with their own firewalls to protect them from outside threats.

Tune Load Generators
To ensure that your load generator machines in the cloud are capable of generating large loads, you must properly tune the system to support the creation of a high number of sockets and threads per process. In addition, allocate an appropriate heap size for Java-based load generators. The default settings for a typical machine allow all programs to share its resources fairly. In the case of load generators, the machine is dedicated to a single task, so you can improve performance by allocating a significantly larger share of the available resources to the load generation tasks.

Monitor Your Servers
Once you've identified a performance bottleneck, you need information to track down its root cause. This information should be gathered during the test by monitoring each component of the infrastructure including application servers and database servers. Specifically, you want to monitor both the system - including the operating system, disks, and network - and the server software - including connection pools, threads, cache hits, and indexes.

Linking all the information gathered during the tests with the tests themselves is much easier when the monitoring is integrated with your load testing tool. This enables you to correlate the response times and errors generated by load testing with the monitored data to track down the cause of problems quickly. A cloud testing solution that has no ability to monitor activity inside the firewall cannot integrate and correlate the tests it initiates from the outside with what is happening on the inside. With such a setup, test engineers will not have all the information they need to quickly identify the sources of performance problems.

Summing It Up
Even with all its potential benefits, cloud testing cannot meet all the challenges facing performance test engineers. In practice, cloud testing is most effective when combined with internal load testing in a two-stage process that makes use of multiple cloud providers and both internal and external infrastructure. You can be optimistic about using the cloud, but don't get caught up in all the hype. The key is to think of cloud testing as the delivery mechanism that is just one (albeit an important one) part of an overall load and performance test strategy.

More Stories By Steve Weisfeldt

Steve Weisfeldt is a Senior Performance Engineer at Neotys, a provider of load testing software for Web applications. Previously, he has worked as the President of Engine 1 Consulting, a services firm specializing in all facets of test automation. Prior to his involvement at Engine 1 Consulting, he was a Senior Systems Engineer at Aternity. Prior to that, Steve spent seven years at automated testing vendor Segue Software (acquired by Borland). While spending most of his time at Segue delivering professional services and training, he was also involved in pre-sales and product marketing efforts.

Being in the load and performance testing space since 1999, Steve has been involved in load and performance testing projects of all sizes, in industries that span the retail, financial services, insurance and manufacturing sectors. His expertise lies in enabling organizations to optimize their ability to develop, test and launch high-quality applications efficiently, on-time and on-budget. Steve graduated from the University of Massachusetts-Lowell with a BS in Electrical Engineering and an MS in Computer Engineering.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@CloudExpo Stories
SYS-CON Events announced today that Windstream, a leading provider of advanced network and cloud communications, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Windstream (Nasdaq: WIN), a FORTUNE 500 and S&P 500 company, is a leading provider of advanced network communications, including cloud computing and managed services, to businesses nationwide. The company also offers broadband, p...
The 4th International DevOps Summit, co-located with16th International Cloud Expo – being held June 9-11, 2015, at the Javits Center in New York City, NY – announces that its Call for Papers is now open. Born out of proven success in agile development, cloud computing, and process automation, DevOps is a macro trend you cannot afford to miss. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the world's large...
Verizon Enterprise Solutions is simplifying the cloud-purchasing experience for its clients, with the launch of Verizon Cloud Marketplace, a key foundational component of the company's robust ecosystem of enterprise-class technologies. The online storefront will initially feature pre-built cloud-based services from AppDynamics, Hitachi Data Systems, Juniper Networks, PfSense and Tervela. Available globally to enterprises using Verizon Cloud, Verizon Cloud Marketplace provides a one-stop shop fo...
Leysin American School is an exclusive, private boarding school located in Leysin, Switzerland. Leysin selected an OpenStack-powered, private cloud as a service to manage multiple applications and provide development environments for students across the institution. Seeking to meet rigid data sovereignty and data integrity requirements while offering flexible, on-demand cloud resources to users, Leysin identified OpenStack as the clear choice to round out the school's cloud strategy. Additional...
The major cloud platforms defy a simple, side-by-side analysis. Each of the major IaaS public-cloud platforms offers their own unique strengths and functionality. Options for on-site private cloud are diverse as well, and must be designed and deployed while taking existing legacy architecture and infrastructure into account. Then the reality is that most enterprises are embarking on a hybrid cloud strategy and programs. In this Power Panel at 15th Cloud Expo (http://www.CloudComputingExpo.com...
We are all here because we are sold on the transformative promise of The Cloud. But what good is all of this ephemeral, on-demand infrastructure if your usage doesn't actually improve the agility and speed of your business? How must Operations adapt in order to avoid stifling your Cloud initiative? In his session at DevOps Summit, Damon Edwards, co-founder and managing partner of the DTO Solutions, will highlight the successful organizational, process, and tooling patterns of high-performing c...
The definition of IoT is not new, in fact it’s been around for over a decade. What has changed is the public's awareness that the technology we use on a daily basis has caught up on the vision of an always on, always connected world. If you look into the details of what comprises the IoT, you’ll see that it includes everything from cloud computing, Big Data analytics, “Things,” Web communication, applications, network, storage, etc. It is essentially including everything connected online from ha...
Software-driven innovation is becoming a primary approach to how businesses create and deliver new value to customers. A survey of 400 business and IT executives by the IBM Institute for Business Value showed businesses that are more effective at software delivery are also more profitable than their peers nearly 70 percent of the time (1). DevOps provides a way for businesses to remain competitive, applying lean and agile principles to software development to speed the delivery of software that ...
Docker offers a new, lightweight approach to application portability. Applications are shipped using a common container format and managed with a high-level API. Their processes run within isolated namespaces that abstract the operating environment independently of the distribution, versions, network setup, and other details of this environment. This "containerization" has often been nicknamed "the new virtualization." But containers are more than lightweight virtual machines. Beyond their small...
The move in recent years to cloud computing services and architectures has added significant pace to the application development and deployment environment. When enterprise IT can spin up large computing instances in just minutes, developers can also design and deploy in small time frames that were unimaginable a few years ago. The consequent move toward lean, agile, and fast development leads to the need for the development and operations sides to work very closely together. Thus, DevOps become...
Cloud Expo 2014 TV commercials will feature @ThingsExpo, which was launched in June, 2014 at New York City's Javits Center as the largest 'Internet of Things' event in the world.

ARMONK, N.Y., Nov. 20, 2014 /PRNewswire/ --  IBM (NYSE: IBM) today announced that it is bringing a greater level of control, security and flexibility to cloud-based application development and delivery with a single-tenant version of Bluemix, IBM's

An entirely new security model is needed for the Internet of Things, or is it? Can we save some old and tested controls for this new and different environment? In his session at @ThingsExpo, New York's at the Javits Center, Davi Ottenheimer, EMC Senior Director of Trust, reviewed hands-on lessons with IoT devices and reveal a new risk balance you might not expect. Davi Ottenheimer, EMC Senior Director of Trust, has more than nineteen years' experience managing global security operations and asse...
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at Internet of @ThingsExpo, James Kirkland, Chief Ar...
Technology is enabling a new approach to collecting and using data. This approach, commonly referred to as the "Internet of Things" (IoT), enables businesses to use real-time data from all sorts of things including machines, devices and sensors to make better decisions, improve customer service, and lower the risk in the creation of new revenue opportunities. In his General Session at Internet of @ThingsExpo, Dave Wagstaff, Vice President and Chief Architect at BSQUARE Corporation, discuss the ...
The security devil is always in the details of the attack: the ones you've endured, the ones you prepare yourself to fend off, and the ones that, you fear, will catch you completely unaware and defenseless. The Internet of Things (IoT) is nothing if not an endless proliferation of details. It's the vision of a world in which continuous Internet connectivity and addressability is embedded into a growing range of human artifacts, into the natural world, and even into our smartphones, appliances, a...
"BSQUARE is in the business of selling software solutions for smart connected devices. It's obvious that IoT has moved from being a technology to being a fundamental part of business, and in the last 18 months people have said let's figure out how to do it and let's put some focus on it, " explained Dave Wagstaff, VP & Chief Architect, at BSQUARE Corporation, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
"Our premise is Docker is not enough. That's not a bad thing - we actually love Docker. At ActiveState all our products are based on open source technology and Docker is an up-and-coming piece of open source technology," explained Bart Copeland, President & CEO of ActiveState Software, in this SYS-CON.tv interview at DevOps Summit at Cloud Expo®, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
DevOps Summit 2015 New York, co-located with the 16th International Cloud Expo - to be held June 9-11, 2015, at the Javits Center in New York City, NY - announces that it is now accepting Keynote Proposals. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete...
What do a firewall and a fortress have in common? They are no longer strong enough to protect the valuables housed inside. Like the walls of an old fortress, the cracks in the firewall are allowing the bad guys to slip in - unannounced and unnoticed. By the time these thieves get in, the damage is already done and the network is already compromised. Intellectual property is easily slipped out the back door leaving no trace of forced entry. If we want to reign in on these cybercriminals, it's hig...