Using Clones to Streamline Development
Contents
1. Set the virtual machine to template mode Select VM gt Settings and select the Options tab Select Advanced and select Enable Template mode to be used for cloning Virtual Machine Settings Hardware Uptions Settings Summary Process priorities Gj General Windows 2000 Professional Input grabbed e Power 9 Shared Folders Enabled Input ungrabbed E Snapshots These settings overde the global values specified in S Guest isolation Crag and drop enabled Edit gt Preferences gt Priority m Advanced Normal oral Settings C Run with debugging information Disable acceleration C Log virtual machine progress periodically Enable Template mode to be used for cloning Using Clones to Streamline Development E vmware Cloning a Virtual Machine from the Repository To access and use the repository open the virtual machine you want and clone the appropriate snapshot to the local test or development machine 1 Open the virtual machine with the environment you want In the Snapshot Manager Snapshot gt Snapshot Manager select the snapshot with the specific operating system version service pack level or applications you want and select Clone BI Windows 2000 Professional Snapshot Manager P 0 0 Windows Winzk Pro Win k Pro 2000 Prof Base SP1 a Wink Pro Wink Pro Wink Pro You 4re SP 4 Here Snapshot created 6 3 2005 4 34 10 AM Name wWinZk Pro SPS Description Windows 2000 P2. and install VMware Tools as described in the Workstation 5 User s Manual Power off the virtual machine You are about take a snapshot of the virtual machine in its current state a clean Windows 2000 installation with no Service Packs loaded Since users will be making clones from the snapshot you want the snapshot of the machine in a powered off state you cannot clone a snapshot that is taken while the virtual machine is powered on Of course a user could always restore the desired snapshot power off the virtual machine and then clone it But by powering off before you take the snapshot you save your users from going through the extra steps of restoring and powering off the virtual machine every time they want to clone it Take a snapshot VM gt Snapshot gt Take Snapshot and give it an appropriate name and description such as Win2k Pro Base Windows 2000 Professional Take Snapshot Winzk Pro Base Description Windows 2000 Professional installed Cancel 4 Power on the machine and install SP1 Power off the virtual machine and take a snapshot naming it Win2k Pro SP1 Using Clones to Streamline Development E vmware 5 Power on the machine and open the Snapshot Manager VM gt Snapshot gt Snapshot Manager ER Windows 2000 Professional Snapshot Manager tl i gt Fo Windows Winegk Pro Win k Pro You Are 2000 Prof Base SP1 Here Snapshot details aes Tele Snot pers
3. Delete Planning Snapshots for Best Performance The next step is to load SP2 and take another snapshot We could do that from the current You Are Here position building the SP2 snapshot on the SP1 snapshot and then the SP3 snapshot on the SP2 snapshot and so on producing a chain of snapshots like this Ei Gi gt G G GF Windows Winek Pro WinekPro Wingk Pro Win k Pro Winek Pro You re 2000 Prof Base SFI SP2 SPS oP 4 Here However for this scenario a linear chain of snapshots is not the best strategy for performance As the chain of snapshots gets longer each succeeding snapshot takes longer for Workstation to work with since it must read all the prior images in the chain to construct the current snapshot As you proceed farther along the chain performance can degrade In some situations this may be an acceptable tradeoff If you want to preserve a historical trail of a particular sequence of actions a chain of snapshots may be necessary For our current task however to improve performance we want to minimize the number of preceding snapshots that any snapshot is based on To do this we need a snapshot tree that looks like this Hi Gi amp Windows Winegk Pro Winzk Pro 2000 Prof Base Winzk Pro SP Q winzk Pro Winek Pro You Ore SF4 Here Using Clones to Streamline Development E vmware 1 Select the Win2k Pro Base snapshot and select Go To We want to base the next sn
4. machines on every desk However while this strategy guarantees developers access to the machines they need the hardware costs can quickly become prohibitive Using Clones to Streamline Development E vmware Perhaps even more significantly this strategy does little to reduce the huge overhead associated with setting up and tearing down development and test configurations The burden on IT may be reduced somewhat but only because the setup and teardown work has been assumed by the individual developers and testers The overhead remains it has merely been distributed over a wider range of personnel Virtualization VMware Workstation Provides an Efficient Alternative In recent years virtualization has changed this landscape considerably VMware Workstation enables developers to store any number of standard x86 based configurations as virtual machines already loaded with any of a wide range of Windows and Linux operating systems browsers and other applications Engineers can use these virtual machines instead of physical hardware to develop and test multitiered applications on a single piece of hardware Because virtual machines are software entities they can be easily copied cloned reset and reused with a few mouse clicks A company can create a repository of pre loaded virtual machines in every desired configuration Each machine requires just a single setup From these template virtual machines individual developers can downlo
5. virtual machine can be stored on the network Then any developers with network access can download a lightweight linked clone in minutes When the problem is solved teardown is as simple as deleting the clone Of course if the clone will be used in a laptop or some other setting where it will not have access to the parent virtual machine you can make a full clone which is independent of the parent machine You might also choose to make a full clone if performance is more important than conserving disk space or speeding the cloning process Because a full clone s virtual disk is local and not shared with the parent virtual machine across a network it can perform better Using Clones to Streamline Development E vmware Scenario Creating and Using a Repository of Test Environments in Virtual Machines One way you can use clones to make your development environment more efficient is by creating a repository of test environments You can store a range of environments as a series of snapshots in virtual machines Then your engineers can clone any of those snapshots as a separate virtual machine that they can download and use For this scenario suppose that you want to establish a repository of Windows 2000 environments at each Service Pack level that you develop and test in Create a Virtual Machine and Snapshots In Workstation 5 1 Begin by creating a new virtual machine Install Windows 2000 as the guest operating system
6. 8 2005 VMware Inc All rights reserved Protected by one or more of U S Patent Nos 6 397 242 6 496 847 6 704 925 6 711 672 6 725 289 6 735 601 6 785 886 6 789 156 and 6 795 966 patents pending VMware is a registered trademark and the VMware boxes logo GSX Server ESX Server Virtual SMP VMotion and VMware ACE are trademarks of VMware Inc Microsoft Windows and Windows NT are registered trademarks of Microsoft Corporation Linux is a registered trademark of Linus Torvalds All other marks and names mentioned herein may be trademarks of their respective companies Revision 20050608 Item NP ENG Q205 105
7. How do you want to clone this virtual machine Clone method Create a linked clone A linked clone ts a reference to the original virtual machine and requires less disk space to store However it cannot run without access to the original virtual machine Create a full clone A full clone is a complete copy of the original virtual machine at its current state This virtual machine is fully independent but requires more disk space to store Using Clones to Streamline Development E vmware 2 Name the clone and save it to your local machine Remember if the clone is linked the clone must be able to access the parent virtual machine Clone Virtual Machine Wizard Name of the New Virtual Machine What name would you like to use for this virtual machine Virtual machine name Clone of Windows 2000 Professional SP3 Location C Wirtual Machines Clone of Windows 2000 Professional SP3 3 Click Finish If you are creating a full clone the cloning process may take a few minutes The virtual machine is ready to use One thing to remember the clone you have just made is from a single snapshot of the parent machine The clone does not retain the multiple snapshots of the parent Before working with the clone you should take a snapshot so you can restore the virtual machine to its clean just installed state at any time VMware Inc 3145 Porter Drive Palo Alto CA 94304 www vmware com Copyright 199
8. Using Clones to Streamline Development E vmware VMware Workstation Using Clones to Streamline Development In recent years the trend in software development has been toward applications that are configured on multitier platforms and delivered via Web browser across the Internet or an intranet While this model with browser based delivery of applications and services offers irresistible cost savings in delivering and supporting products it also greatly increases the complexity involved in creating those products To produce applications for this environment software developers and testers now require a multitiered platform under their control deployed maintained and readily available to Development and QA Browser based multitier applications must be developed and tested against an ever wider variety of hardware platforms operating systems and browsers all with multiple versions Many software companies report that the overhead involved in IT setup and teardown of lab machines consumes 25 to 30 percent of the development budget a staggering cost This technical note shows one way to address this challenge through virtualization by using Workstation 5 with its linked clones and multiple snapshots features to set up a repository of clean development environments in a series of virtual machines from which developers can quickly clone and download a desired setup in minutes e Traditional Approaches to Providing Developmen
9. ad a clean just installed configuration they need simply by cloning the appropriate virtual machine Workstation 5 Cloning and Multiple Snapshot Features The new Workstation 5 linked clone and multiple snapshot features make it easy to set up a repository of development environments in virtual machines For example you can create a virtual machine install an operating system and load various service packs saving each as a separate snapshot a scenario discussed in detail in this tech note A developer can then open the virtual machine from your repository go to the appropriate snapshot and clone it to a local drive in a few minutes Using linked clones makes it even faster to download a clean environment into a virtual machine When you make a linked clone from a virtual machine the clone uses the virtual disk of the parent virtual machine it was cloned from Since virtual machines can be large this dramatically reduces the time it takes to clone a virtual machine and the amount of disk space the clone uses By making it so easy to quickly create a lightweight clone of an existing environment linked clones also facilitate collaboration among developers and testers For example suppose a developer is working on a bug and wants help from other developers or testers The entire setup containing the bug including the operating system and all applications involved can be captured in a snapshot or a series of snapshots and the
10. apshot image for SP2 on the Base image instead of the SP1 image Reopen the Snapshot Manager which closed when you selected Go To Note the You Are Here position Now changes you make will be based on the Base snapshot m i Windows 2000 Professional Snapshot Manager 0 0 Windows wWinzk Fro Winzk Pro 2000 Prof Base SP 1 You 4re Here 2 Close the Snapshot Manager power on the VM and install SP1 and SP2 Power off the virtual machine and take a snapshot naming it Win2k Pro SP2 Bh i Windows 2000 Professional Snapshot Manager TGG Windows Winzk Pro Winek Pro 2000 Prof Base SP1 B Winzk Pro You Ore SP Here 3 Open the Snapshot Manager select the Win2k Pro Base snapshot and select Go To Again we want to base the next snapshot for SP3 on the Base snapshot not on the SP2 snapshot to minimize the length of the snapshot chain and maximize performance Power on the virtual machine and install SP1 SP2 and SP3 Power off the virtual machine and take a snapshot naming it Win2k Pro SP3 ER Windows 2000 Professional Snapshot Manager A G Windows Winegk Pra Win k Pro 2000 Prof Base SP1 Winzk Pro Winzk Pro You Are SPS Here 5 Continue in this way until you have snapshots of each Service Pack level you want in the repository Using Clones to Streamline Development E vmware The virtual machine now contains a clean
11. installation of Windows 2000 at each SP level You could use the same procedure to create virtual machines containing any number of standard development environments with any of the operating systems supported by Workstation You could also create virtual machines with applications various Web browsers for example already installed Once you have created a repository of virtual machines any developer and tester with network access can set up a clean installation of any of the environments stored in the repository in minutes simply by cloning a virtual machine as described in Cloning a Virtual Machine from the Repository on page 7 Setting the Virtual Machine to Template Mode Next set the virtual machine to template mode This ensures that users will not change the virtual machine This is especially important because users will often make linked clones from the virtual machine Since linked clones share and depend upon the virtual disk of the parent virtual machine it is especially important that virtual machines in the repository are not changed When the virtual machine is in template mode it cannot be deleted and none of the template s snapshots can be deleted Note The system administrator should make sure that users do not have write permissions for the virtual machine s files This precaution prevents users from disabling template mode for a virtual machine or inadvertently deleting a virtual machine through the file system
12. rofessional SP3 2 The Clone Virtual Machine Wizard opens with the snapshot you selected as the clone source Click Next Clone Virtual Machine Wizard Clone Source Which state do you want to create a clone from Clone source From current state Creating a linked clone from the current state will create a new snapshot From snapshot win k Pro SP3 wt Description Windows 2000 Professional SPS Using Clones to Streamline Development E vmware Selecting the Type of Clone Full or Linked You can create a full clone or a linked clone e A linked clone is a copy of a virtual machine that shares virtual disks with the parent virtual machine This conserves disk space and allows multiple virtual machines to use the same software installation A linked clone must be able to access the parent virtual machine e A fullclone is an independent copy of a virtual machine and does not need access to the parent virtual machine Creating a full clone is an appropriate choice if you want to create a totally independent clone to use on a laptop for example Also because a full clone accesses its virtual disk locally instead of across a network to the parent virtual machine it may be preferable to a linked clone when performance is more important than conserving disk space Follow these steps to create a clone 1 Select the type of clone you want and click Next Clone Virtual Machine Wizard Clone Type
13. t Environments on page 1 e Virtualization VMware Workstation Provides an Efficient Alternative on page 2 e Workstation 5 Cloning and Multiple Snapshot Features on page 2 e Scenario Creating and Using a Repository of Test Environments in Virtual Machines on page 3 e Cloning a Virtual Machine from the Repository on page 7 Traditional Approaches to Providing Development Environments One traditional way to create a development and test environment is to set up a lab with a pool of machines shared by Development and QA and maintained by an IT department This saves money in hardware but at a great cost in efficiency Typically in this arrangement a developer must request access to a particular configuration of hardware operating system and browser which in turn must be set up by IT In essence the software engineer must make an appointment to gain access to the necessary development environment and IT personnel must set up and tear down again and again every possible configuration needed by each developer and tester For the developer and tester this arrangement is frustrating and inefficient they must contend and wait for restricted access to a limited number of machines Inevitably this results in dead time for the engineer delays in production and an increase in the time to market for the product Alternatively some companies have chosen to provide each developer and tester with a separate hardware setup with servers and client
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