Cloud testing and support to the software lifecycle

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Politecnico

di Milano

Cloud testing and support to the software lifecycle

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The software lifecycle and the cloud

!

PaaS/IaaS approaches seen so far mostly dedicated

to offer run-time features

!  

Google App Engine and MS Azure also offer

programming features

!  

IDEs

!  

Programming models (e.g., web role/worker role in

Azure, parallelism managed through task queues in

GAE)

!  

Coverage of other aspects of the software lifecycle

!  

Cloud testing and testing Cloud applications

!

CloudBees

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Software testing

!  

Software testing is the process of assessing, through

execution, the functional and non-functional

characteristics of a program

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For large systems:

!  

High number of test cases (thousands)

!  

Need to execute the same tests several times during

the day

!  

Need to handle testing for multiple configurations (e.g.,

multiple browsers, various operating systems, various

versions/types of databases,

…

)

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Software testing and the Cloud

Cloud characteristics

Testing problems

Possibility to have a large

number of parallel executions

è

Large test suites

Possibility to exploit resources

(and pay for them) only when

needed

è

Execute tests along the day

Possibility to build virtual

machines each one with a

different configuration

è

Handle different

configurations

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Cloud testing

!  

Cloud testing means using the Cloud to support the

testing phase

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Risks of Cloud testing

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Testing artifacts need to be migrated to the cloud

even though still kept in synch with other

development activities

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Artifacts to be migrated

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Test cases/test suites

!  

Scaffolding

!  

Software to be tested

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Testing tools

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Specific Cloud issues, e.g., security, should be taken

into account

!  

Test code, libraries, dependencies may not be

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Characteristics of applications that can

be tested in the Cloud

!  

Test case independence

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If test cases are temporally dependent from each other,

they cannot be run in parallel

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Standard operating environment

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Otherwise incompatibilities may arise

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Availability of programmatic interfaces

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GUI-based testing could be less convenient on the

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Types of testing suitable for the Cloud

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Unit testing

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Easy to automatize

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A killer application of Cloud testing

!  

High Volume Automated Test

!  

Looks for failures that happen only after a prolonged test

(e.g., deadlock, race conditions,

…

)

!  

Resource intensive

!  

It can rely on the large number of resources offered by the

Cloud

!  

Performance testing

!  

Used to determine application throughput, resolving

concurrency issues, tuning server response time, assessing

availability

!  

In a Cloud environment it is possible to emulate load on

demand

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What do we install on the Cloud?

!  

The entire system to be tested, together with all it is

needed for performing testing

ç

This is what we have

assumed so far

!  

We use the Cloud for hosting/emulating part of the

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Examples of testing tool: D-Cloud

!  

Support execution of tests with fault injection

machine using the fault injection facility implemented in the virtual machine layer.

• The computing resources can be managed flexibly. If

resources are available, then test cases can be executed quickly by simultaneously using the resources.

• D-Cloud automates testing using descriptions of the

sys-tem configuration and the test scenario to execute tests on cloud computing systems.

A. Fault injection in a virtual machine

D-Cloud uses a virtual machine to execute system tests. The virtualized hardware device can simulate failures on the guest OS, and fault injection using virtual machines allows system tests to be executed without changing the program. Using the virtual machine, D-Cloud can test software running in not only the userland layer but also in the kernel layer. When software bugs on the kernel layer are detected during a system test, the OS may hang-up automatically due to a kernel panic. When the system runs on real machine, it is difficult to obtain helpful information for the bug fix in this case, because the user cannot manipulate the OS under the kernel panic. However, when using a virtual machine, a bug in the OS running on the virtual machine does not affect the host OS running on a physical machine. Therefore, the tester can continue system tests, and the tester can collect information for debugging even if the guest OS crashes. Furthermore, the snapshot of the previous state in the guest OS permits the operation to return until the desired state repeatedly.

B. Management of computing resources

For developing reliable systems, it is important that system tests must be executed for as many cases as possible in order to find and fix as many bugs as possible. In addition, in order to execute many tests, a large amount of resources must be managed efficiently and flexibly. In D-Cloud, resources are managed by a cloud computing system. For example, a number of systems that require high reliability and dependability consist of multiple nodes linked by a network. In this case, D-Cloud can test such distributed systems using several guest OSes.

C. Automating system configuration and testing

D-Cloud automates the system setup process of the tested system and the test process, including the fault injection, based on a scenario written by a tester. When the tester writes a number of configurations of system test environments in a scenario description file, D-Cloud sets up appropriate test environments and executes appropriate tests automatically. Therefore, D-Cloud enables the behavior of dependability functions on the system to be tested exhaustively and enables system tests to be executed quickly.

III. DESIGN OF D-CLOUD

D-Cloud uses QEMU as virtualization software and Euca-lyptus, which is an open-source implementation having the same API as AmazonEC2[3]. Figure 1 shows an overview of D-Cloud. D-Cloud consists of the following components:

Fig. 1. Configuration of D-Cloud

1) QEMU nodes, which are available with the fault injec-tion facility.

2) The controller node, which manages the QEMU nodes using Eucalyptus.

3) D-Cloud frontend, which issues test and fault injection commands and transfers input/output data with QEMU nodes.

A. Fault injection using QEMU

D-Cloud uses QEMU as a virtualization software. The advantages of using QEMU are described following.

• QEMU can emulate a number of hardware devices. Thus,

QEMU may control several hardware faults in the guest OS.

• The QEMU source codes are available as open-source

software. This allows modification to the hardware emu-lation codes in order to add the fault injection function.

• QEMU can isolate the host OS from the guest OS. In

addition, QEMU may insulate the computing host from anomalous behavior of the guest OS during various tests. 1) Type of fault injection: Table I lists the types of fault injection . Here, we implement the fault injection mechanism for the hard disk controller, the network controller, and the memory as target devices.

2) Reproducibility in fault injection: Reproducibility is important in fault tolerant testing using fault injection. If a testing environment has reproducibility, then the tester can find errors that occur under specific conditions and can fix such bugs. In particular, in many cases of hardware device errors, we cannot predict the effects of bugs, and these effects are usually not repeatable. However, since hardware errors can be emulated anytime and anywhere using a virtual machine, the costs associated with using a virtual machine are lower than those associated with using physical machines.

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TABLE I

TYPES OF FAULT INJECTION

device contents value Hard disk Error of specified sector badblock

Specified sector is read-only readonly Error detection by ECC ecc Received data contains error corrupt Response of disk becomes slow slow Network 1bit error of packet 1bit 2bit error of packet 2bit Error detection by CRC crc

Packet loss loss NIC is not responding nic Memory Bit error bit Byte at specified address contains error byte

B. Managing resources using Eucalyptus

D-Cloud manages virtual machine resources using Euca-lyptus. Eucalyptus is a cloud computing infrastructure that manages machine resources flexibly using a virtual machine. D-Cloud consists of multiple QEMU nodes, which execute guest OSes, and a controller node, which controls all of the guest OSes.

The procedures to manage machine resources are shown as follow.

1) A tester uploads OS images to the controller node and registers the machine images to the D-Cloud frontend. 2) The controller node transfers OS images to QEMU

nodes.

3) The OS images are booted as a guest OS on QEMU nodes.

After the controller node receives the request to boot a guest OS, the controller node transfers the OS images to QEMU nodes, which are available to run the OS images. Thus, the tester does not need to be aware of computing resources on D-Cloud.

C. D-Cloud frontend

D-Cloud frontend manages guest OSes, configures system test environments, and transfers various data from the tester to a guest OS executed for the purpose of system testing.

D-Cloud frontend performs its function as follows:

1) D-Cloud frontend receives a test scenario, a test pro-gram, input data, and an execution script from a tester. 2) D-Cloud frontend then issues a request to boot a guest

OS to the controller node.

3) D-Cloud frontend then transfers the test program, the input data, and the execution script to the guest OS. 4) D-Cloud frontend then issues the fault injection

com-mand to the target guest OS.

5) Finally, D-Cloud frontend collects the output data, logs, and snapshots.

Since D-Cloud frontend collects data obtained in the test, the tester can download these data anytime. If the tester checks the output and traces the operation using saved snapshots, the tester can discover some bugs and investigate these bugs in detail.

Fig. 2. Example XML scenario

IV. SYSTEM CONFIGURATION AND SCENARIO DESCRIPTION

D-Cloud executes system tests according to a scenario written in XML. By describing the scenario, the tester si-multaneously executes various system tests. Figure 2 shows a complete example of a scenario statement. The scenario statement consists of four parts defining the test as follows:

• Description for hardware environment • Description for software environment • Definition of faults for injection

• Procedure of the entire test

A. Configuration for the hardware environment

The definition of the hardware environment is given in the “machineDefinition” element. Table II lists the contents of the “machineDefinition” element. Next, the definition of the hardware environment is described in the following. The “machineDefinition” element can hold multiple “machine” el-ements. The “machine” element includes five elements (name, cpu, mem, nic, and id), and these elements are needed for each definition of a hardware environment. The “name” element

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Using the Cloud for emulating part of the

system

!  

Emulation of large traffic in stress and performance

testing

!  

Application-Behavior Virtualization to replace

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SOASTA CloudTest

!  

Use the Cloud to inject large traffic hitting the

application under test

!  

Testing

can happen

also in

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Application-Behavior Virtualization

!  

Focuses on enabling testing when the software under

test includes

!  

Missing/unstable components

!  

Non fully accessible third-party/partner systems and

services

!  

Systems that are too complex for test labs

!  

Enables testers to rapidly isolate and virtualize just

the behavior of the specific dependent components

that they need to exercise in order to complete their

end-to-end transactions.

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Application-Behavior Virtualization

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Steps

!  

Identify the components to virtualize

!  

Capture the behavior of the associated transactions,

messages, services in

virtual assets

!  

Configure the virtual assets parameterizing conditional

behavior, performance criteria, test data

!  

Use the virtual assets to emulate the actual behavior of

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Test environments in the Cloud (1)

Test Environment in Cloud

Attributes of Cloud

solutions

Characteristics Benefits

Advanced virtualization Test resources (infra, tools and

people) are pooled and virtualized

Providing efficient

implementation of independent infrastructure

Rapid Provisioning Test resources are provisioned

on demand

Reducing test setup and

execution time and eliminating errors

Service Catalog ordering Test environment are readily

available

Enabling visibility, control and automation

Elastic scaling Test environment can be

scaled up or down by large factor as the need emerges

Optimizes, infra and software license usage

Flexible pricing Test resources are priced on

supported topology and project phases

Offering pricing options tailored to user resource need

Metering and billing Test resources used in

reserved are charged back to LOBs

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Test environments in the Cloud (2)

Test Environment in Cloud (Contd..)

Attributes of cloud solutions

Characteristics Benefits

Re-platform ability (Compatibility Testing)

Platform based configurations (for testing) can be created and managed

Comprehensive assurance on product / service

Maintenance of multiple test beds based for multiple release testing

Release based configurations (for testing) can be created and managed

Complete assurance on maintenance of product / service

Test factories and TCoE Setups Emerging alternative models for supporting client testing needs

Collaborative platform enables collective productivity

Service virtualization In a multi component

architecture, availability of a dependant component(s) managed for testing

Effective completion of component level testing, despite the dependencies on Critical components

ALM (Application Lifecycle Management) / TLM (Test Lifecycle Management) support

In a multi component

architecture, availability of a dependant component(s) managed

Effective completion of component level testing, despite the dependencies on Critical components

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Test environments in the Cloud (3)

Past

–

Present and future (Test Environment)

Capability Past Present and future

Server / Storage utilization 10-20% 70-90%

Cost Reduction Nil 20-30%

Self Service None Unlimited

Test Provisioning Weeks Minutes

Change Management Months Days / Hours

Release Management Weeks Minutes

Metering / Billing Fixed cost model Granular

Re-platform ability (Compatibility Testing) Prohibitively expensive

Engineering possibility with affordable cost

Maintenance of multiple test best beds for multiple release testing

Prohibitively expensive

Engineering possibility with affordable cost

Multiple Tools testing (Application Security –for false positives –false negatives triangulations)

Prohibitively expensive

Affordable because of utility pricing and improved coverage New Alternate for BCP (Business Continuity

Plan) and DR (Disaster Recovery)

Not Applicable A Distinct possibility

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Testing as a Service (TaaS)

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Potential benefits

!  

Tool license and infrastructure costs on a pay-per-use

basis

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Flexibility and wide range

!  

No setup and procurement time wastage

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No need of hiring expert people

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The landscape of current offering [CSC]

Cloud Based Testing Service Offerings under TaaS Ecosystem

Platforms

Windows (Multilingual, Multi

CPUs) Linux (Red hat, Linux, Debian)

MS-SQL. Oracle, DB2,

Informix, MySQL, Teradata Sun Solaris

Elastic servers (Tomcat, My

SQL combination s)

Borland ES, Cold fusion, Tomcat, Web logic, Web Sphere, Web Application server

(SAP), ATG Dynamo, JBOSS

Tools Sandbox

Apps

& Services Client / Server

Enterprise Applications – SAP, Oracle, Cadence, PTC, Sugar CRM CSC TRUSTED CLOUD Powered by Web Application Performance Testing Web Applications Industrialized Solution – CAT / SAPT FUTURE OFFERINGS CSC OPEN SOURCE CLOUD

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TaaS experience at CSC

CSC Client

Test Requirements & Application Components

CSC On-Demand Testing in Cloud

FTP / URL

Virtual Test lab using SkyTap

Database servers Web Server Application Servers

Application Under Test Automated Software Quality Tools

Infrastructure Stabilization

Test Strategy & Planning

Test Execution Test Summary Reports

Certify Application Customer requests Testing from CSC Online portal / Telesales Provisioning / Scheduling of Tests CSC conducts Testing CSC publishes Test Results &

Reports Collaboration Customer Sign-off Cloud Orchestration CSC Client CSC & Client SOASTA Cloud

Typical Engagement Model

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TESTING CLOUD-BASED

APPLICATIONS

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What things are the same about

testing cloud solutions?

From Paul Selway and Scott Rostal, Testing in the Cloud,

http://www.tcqaa.org/documents/Testing in the Cloud.ppt

C 

Requirements coverage based testing

C 

Risk-based structured test approach

C 

Test Plan / Test Phases

C 

Test Cases / Test Data / Test Automation

C 

Defect Management / Functional Test

C 

Use of off-shore resources / Virtualization

C 

Politics {Quality / Schedule / Resources}

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What is different about testing

cloud solutions?

From Paul Selway and Scott Rostal, Testing in the Cloud,

http://www.tcqaa.org/documents/Testing in the Cloud.ppt

D 

Shared multi-tenant test environments

D 

Security (Test User IDs / SSO)

D 

Integration of on/off premise systems

D 

Performance / volume test

D 

Defect isolation

D 

Documentation of

“

Out Of the Box

”

reqs

D 

Release Management

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What is harder than expected?

!  

Isolating the architectural components for a performance

test

!  

Understanding that a cloud solution vendor delivers new

releases which you have to take!

!  

Accepting that you have a

“

black box

”

in your environment

!  

Determining who owns defects

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What is easier than expected?

!  

Overlapping Test phases

!  

End User Adoption

!  

Use of off-shored test resources

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Functional

!  

Performance

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Enhancements to testing methodology

for cloud testing

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Test planning

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Test design

!

Cloud setup

!  

Requires familiarity of the target Cloud environment and of

its key functions

!  

Understanding of Cloud monitoring tools is essential

!

Test execution

!  

Requires usage of additional resources (computational units,

storage, communication channels), possibly TaaS

!  

Remediation

!

Closure

!  

All used resources need to be released

!  

Storage resources could be used for archiving test cases,

results, used VMs could be saved as images and for later

use

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Testing focuses when migrating an

application in the Cloud

!  

Test application changes needed to adapt the

application to the Cloud

!  

Check on-premise interfaces

!  

Check data migration and backup mechanisms

!  

Focus on new security aspects that may have added

!  

Encrypted data in cloud storage

!  

New secure channels

!  

Performance and scalability

!  

Compare with on-premise setting

!  

Make sure that you are making good use of the

features offered by the Cloud

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CloudBees main characteristics (1)

!  

Differently from GAE (and Azure), relies on well-known, state of

the art components

!  

Tomcat

!

Jboss 6 Application Server

!  

MySQL

!  

Can execute any standard Java web application

!  

An application built for CloudBees can be moved to any other

environment, provided that you install the state of the art

components it uses

!  

No vendor lock-in

!  

Offers a load balancer and manages an application cluster

!  

The developer, however, is in charge of maintaining HTTP

session on some repository

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CloudBees main characteristics (2)

!  

Supports a continuous integration process through an

on-demand Jenkins (Hudson) service

!  

Each time a new version of a software component is

released, the system is automatically built and verified

against an array of tests

!  

The build process can take into account the definition

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CloudBees partners eco-system

!  

Examples

!  

New Relic: performance monitoring service

!

Papertrail: aggregation and analysis of log files

!  

Sauce Labs (Selenium): automated in-browsed testing

of web applications

!

MongoHQ (MongoDB): noSql database

!

SendGrid: SMTP service

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References

!  

Cloud testing

!

Parveen, T.; Tilley, S.; , "When to Migrate Software Testing to the

Cloud?," Software Testing, Verification, and Validation Workshops

(ICSTW), pp.424-427, 6-10 April 2010

!  

Banzai, Takayuki et al., "D-Cloud: Design of a Software Testing

Environment for Reliable Distributed Systems Using Cloud

Computing Technology," Cluster, Cloud and Grid Computing

(CCGrid), 2010 10th IEEE/ACM International Conference on , pp.

631-636, 17-20 May 2010

!  

SOASTA website

http://www.soasta.com/

!

Lef Grant Briefing, H.KOTHANDARAMAN, Testing applications n

Cloud,

http://assets1.csc.com/lef/downloads/

LEFBriefing_TestingApplicationsCloud_021011.pdf

!  

WAYNE ARIOLA, The Next Generation of Test Environment

Management: Application-Behavior Virtualization,

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References

!  

Testing cloud-based applications

!  

Paul Selway and Scott Rostal, Testing in the Cloud,

http://www.tcqaa.org/documents/Testing in the Cloud.ppt

!  

RAJAGOPAL SATTALURI, Testing Considerations for Application Migration

to Cloud Computing, http://cloudcomputing.sys-con.com/node/1703085

!