I point this out about script packages because recently I put one together that is not a WebSphere Application Server administration task, but does provide configuration logic common to many WAS deployments. Specifically, I put together a script package that configures an IBM HTTP Server to be a reverse proxy server. This of course, allows clients to send requests to the IBM HTTP Server and have those requests pass through to a specified back-end destination (i.e. a service hosted on WebSphere Application Server) based on URI paths.
The script package is not all that different from many of the ones I put together. It contains a shell script (which provides configuration and orchestration logic) as well as a cbscript.json file that defines the script package's characteristics when I upload it into WebSphere CloudBurst. The notable difference in this script package is that I include a Perl script that modifies the IBM HTTP Server configuration file. This just reiterates the point that you are not limited to only wsadmin and shell scripts within your script packages.
The workings of the script package are quite straightforward. It starts with a call to the shell script that modifies the IBM HTTP Server's configuration file to ensure the loading of a couple proxy modules:
sed -i s/"#LoadModule proxy_module modules\/mod_proxy.so"/"LoadModule proxy_module modules\/mod_proxy.so"/g $HTTP_CONF
sed -i s/"#LoadModule proxy_http_module modules\/mod_proxy_http.so"/"LoadModule proxy_http_module modules\/mod_proxy_http.so"/g $HTTP_CONF
As you can see, the createProxy.pl script accepts a single argument. This argument represents the reverse proxy configuration information provided by the user during deployment. The Perl script parses the single argument and creates the appropriate proxy directives in the IBM HTTP Server's configuration file:
After the invocation of the script above, control returns to the shell script. The shell script restarts the IBM HTTP Server so that the configuration changes take place. The result is an up and running IBM HTTP Server acting as a reverse proxy based on information supplied during deployment. The listings here do not show the full script package, but I hope to have it up on our WebSphere CloudBurst Samples Gallery soon.
If the script above provides some configuration logic you can use, that is good. However, my main point for bringing it up here is to point out that WebSphere CloudBurst script packages can be more than shell and wsadmin scripts that perform WebSphere Application Server configuration tasks. You can use them to do any sort of scripted activity that is essential to your application middleware deployment process. Happy scripting!
If you follow this blog often, you know that from time to time I like to post frequently asked questions. Well, it's been a while since I have done that, and since then I have added some new questions to my list -- along with some regulars. Take a look below, and if I don't answer your question feel free to leave a comment!
Can IBM Workload Deployer deploy software that is not IBM software? Yes. You can use one of the included images as a springboard and customize them with your own software via extend and capture. Additionally, you can use the IBM Image Construction and Composition Tool (I'm getting ahead of myself here) to create your own custom images from the ground up and use those within IBM Workload Deployer.
Can I use VMotion for the systems I deploy with IBM Workload Deployer? Yes. IBM Workload Deployer has tolerated the use of VMotion since the WebSphere CloudBurst days (see the Additional Considerations section on this page for more information). IBM Workload Deployer v3 introduced the notion of virtual machine mobility initiated directly from the appliance. This capability takes advantage of VMotion in the case of VMware-based cloud environments.
Can IBM Workload Deployer deploy just a base operating system? Yes. IBM Workload Deployer v3 introduced a base operating system image that contains 64-bit Red Hat Enterprise Linux. Internally, IBM Workload Deployer uses this as the foundation on top of which virtual application patterns are deployed. You can use it to deploy virtual machines containing just the base OS, or you can customize it to deploy software of your choosing. (As an aside, IBM Workload Deployer v3.1 will include a base operating system image for AIX)
Can I automate the process of calling/using IBM Workload Deployer? Yes. IBM Workload Deployer is built to fit a specific need -- creating and managing a cloud of middleware and middleware-based workloads. In that light, it would be a shortcoming if IBM Workload Deployer did not to fit well into more holistic or enterprise-wide cloud management systems. The REST API and CLI allow you to automate the use of IBM Workload Deployer, thereby allowing it to be mashed up into other processes.
Can I group two appliances together for high availability? Yes. IBM Workload Deployer v3.1 introduces the ability to configure appliances in a master/slave setup. You can connect two appliances, allow them to share a floating IP address, and be confident that data is continuously replicated between the two. If one appliance fails, the other appliance picks up the floating IP ensuring continuous service.
Are images created using the Image Construction and Composition Tool supported for use within IBM Workload Deployer? Yes. Part of the new IBM Workload Deployer 3.1 announcement was a statement of support for using images created by the Image Construction and Composition Tool as a component of your virtual system patterns. This is a very important enhancement as it allows you to extend the set of content deployed by IBM Workload Deployer while being sure that you are operating within the boundaries of intended use.
Can I use IBM Workload Deployer to provision to public clouds? No... and yes. If you install an IBM Workload Deployer appliance in your datacenter, you cannot use it to deploy to a public cloud environment. However, you may have recently heard about the IBM SmartCloud Application Services portfolio. IBM has announced that the pattern-based provisioning that one gets with IBM Workload Deployer will also be available as part of this portfolio. This means that you will be able to build and deploy patterns using a service hosted on the IBM SmartCloud. Further, your deployed systems will run on the IBM SmartCloud. Check out this demo for more information.
** IBM Workload Deployer 3.1 firmware is available on 11/18.
I spent most of my time growing up doing two things, going to school and playing sports. I made many fond memories -- mostly from the latter :) -- and learned more than a few lessons over that time. Of all of those lessons, there was one in particular that stuck out in both the classroom and on the baseball diamond: Sometimes you have to get back to the basics.
In that vein, I think it is time to revisit the basics of WebSphere CloudBurst. In revisiting the basics, I am not talking about the technical basics of the appliance. Rather, I am talking about revisiting exactly why WebSphere CloudBurst exists in the first place. In other words, let's take a look at the problem domains WebSphere CloudBurst addresses, and let's discuss a little bit about how the appliance does so.
Application-centric cloud computing is the main thrust behind the new capabilities of IBM Workload Deployer v3.0. But what does that really mean? After all, application-centricity is really just a concept. Granted, it is an important concept, but it is fairly meaningless until it is put into action or implemented. IBM Workload Deployer does just that with its new Virtual Application Patterns (VAPs).
VAPs are the embodiment of the workload pattern approach I briefly discussed in an overview post a few weeks back. The idea with a VAP is to give the user an interface through which they can provide their application, specify dependencies, declare functional and non-functional requirements and then deploy. Of course application middleware is a part of the overall solution, but IBM Workload Deployer has the smarts to build, configure, and integrate the necessary infrastructure in order to support the user's application. This is completely hidden from the user, so they are liberated to focus on the application and its requirements.
If we scratch a bit further beneath the surface of a VAP, we see that these patterns contain three primary pieces. These primary pieces are components, links, and policies, and they are fundamental to understanding how virtual application patterns work. Let's start with the building blocks of VAPs, components. Put simply, components represent different resources and functionality profiles that make up your application environment. As an example, the IBM Workload Deployer Pattern for Web Applications is a VAP that contains components for an EAR file, WAR file, message queue, and any number of other components that are typical requirements for a web application. The components will certainly vary based on the workload type (i.e. the components included in a web application VAP would be different than those included in a batch application VAP), but they are the foundation of any VAP.
From the ground up, the next logical element we come to in the VAP is a link. A link is a way to declare a dependency or integration point between two components. As an example, consider a VAP with a WAR file component and a database component. You might draw a link between the WAR component and the database component to indicate that your web application uses or otherwise depends on the database. IBM Workload Deployer interprets this link, and takes it as a directive to configure the integration between the two components as a part of deployment. In this case, that may mean configuring a data source in the application's container. This is just a simple example, and an application may have any number of links between components.
Finally, we come to the policy element within the VAP. A policy is a way for a user to specify functional and non-functional requirements for their application environment. Users attach policies to the VAP, or to components in their VAP, and IBM Workload Deployer interprets and enforces those policies. In the context of a web application, one example of a policy could be a scaling policy. The scaling policy might indicate scaling requirements for the application that included minimum application instances, maximum application instances, and conditions that triggered scaling activities. IBM Workload Deployer would use the information in a scaling policy within a VAP to appropriately manage the deployed, running environment. Other examples of a scaling policy may include a JVM policy that provides configuration directives for the java virtual machines in your application environment or a logging policy that defines logging configuration options. In any case, the policy element allows VAP builders to influence the configuration and management of the application environment.
In the example VAP below you can see the use of components (Enterprise Application, Database, User Registry, Messaging Service), links (blue lines between components), and policies (Scaling Policy, JVM Policy):
In total, when I look at a VAP a particular word sticks out to me: declarative. VAPs really enable declarative, application-centric cloud computing. What do I mean? By declarative, I mean you are telling IBM Workload Deployer what you want, but not necessarily how you want it done. It is the job of IBM Workload Deployer to take care of the how. This shift in approach to application environments enables the potential for significant savings, and more importantly to me, lays the foundation for a more agile, flexible approach to deploying and managing application environments.
There will be more in the weeks and months to come on IBM Workload Deployer, so stay tuned. I also want to put a plug in for a new blog from Jason McGee. For those that do not know Jason, he is an IBM Distinguished Engineer, and the lead architect behind IBM Workload Deployer. Be sure to check out his blog for insights on this new offering, as well as for all things cloud.
In my last post, I concentrated on the new enhancements to WebSphere CloudBurst 22.214.171.124. One of the major new additions was the introduction of Environment Profiles, and I promised a developerWorks article would be forthcoming. The article is now live along with a demo that showcases the capability of environment profiles.
As I mentioned in my last post, environment profiles center around giving you more customization capability during the pattern deployment process. In WebSphere CloudBurst, the pattern deployment process consists of the five main steps depicted below.
Traditionally, WebSphere CloudBurst controlled the entire deployment process, thus closing it off to the deployer. Environment profiles extend the customization reach of users to be able to effect steps 1-3 in the above diagram. Specifically, environment profiles give you the following control:
Control over the assignment of IP addresses and hostnames to pattern parts: Instead of having WebSphere CloudBurst automatically assign IP addresses, and thus hostnames, to virtual machines during deployment, you can explicitly set both values during the deployment process.
Ability to deploy single patterns to multiple cloud groups: Previously, when deploying a pattern you selected a single cloud group and WebSphere CloudBurst deployed all the parts in the pattern to machines within that cloud group. While this may be okay for many cases, other cases may require you to deploy some parts of the pattern to one group of machines while other parts map to a separate set of machines. Before environment profiles, you could accomplish this with multiple patterns. With environment profiles, you can accomplish it with a single pattern.
Ability to supply virtual machine naming standards: As part of deploying a pattern, WebSphere CloudBurst creates one to many virtual machines with distinct names. Environment profiles allow you to supply a naming standard that WebSphere CloudBurst will use when creating the machines as opposed to default naming schemes previously used.
It is important to note that the use of environment profiles is completely optional, and you can continue to use the traditional deployment process, thereby leaving WebSphere CloudBurst in control. That said, the introduction of environment profiles is a direct response to consistent user feedback we received regarding the need for more control during the deployment process. Based on my user conversations, these profiles address many of said needs in an easy to use, straightforward manner. We are, of course, eager to know what you think. As always, you can let me know right here, through email, or on Twitter (@damrhein).
The 1.1.1 version of WebSphere CloudBurst is now available on the IBM support site, and you can read a bit about it here. I have not blogged about each and every point release of WebSphere CloudBurst here, but this particular one is significant. The 1.1.1 release adds support for IBM's z/VM hypervisor platform as a deployment target.
Quite simply this means that you can now create virtualized WebSphere application environments on the z/VM platform using WebSphere CloudBurst. This starts by first defining target hypervisors, instances of Linux Master Systems, that WebSphere CloudBurst can communicate with to setup virtual machines on z/VM. Coupled with support for the z/VM infrastructure components, there is a new version of the WebSphere Application Server Hypervisor Edition virtual image. While this new image contains the same basic components as the previous hypervisor edition images, it is packaged for the z/VM platform, and it includes a zLinux operating system.
Once you upgrade to WebSphere CloudBurst 1.1.1, you can define your z/VM infrastructure and use the new WebSphere Application Server Hypervisor Edition image to build custom patterns targeted for the z/VM platform. I put together a demonstration that provides a very brief overview of these new capabilities. As always, please reach out if you have any questions about this or any other WebSphere CloudBurst topic.
A couple of weeks ago, I dropped by the Intel Developer Forum to present a session and listen in on a few others. As always in these types of shows, I learned quite a bit. Most strikingly though, I was reminded of something that is probably quite obvious to many of you: Consumer interest in cloud computing will not be letting up any time soon.
Based on this, and some of the other things I heard at the show, I decided to catch up with fellow IBMer Marc Haberkorn. Marc is an IBM Product Manager and is responsible for IBM Workload Deployer amongst other things. I asked him about IBM Workload Deployer, the competition, and cloud in general. Check out what Marc had to say below:
Me:IBM Workload Deployer is one among many of a growing wave of cloud management solutions. How do you differentiate the focus and business value of it versus the myriad of other solutions out there?
Marc: To sum it up, we offer a combination of depth and breadth. IWD delivers both workload aware management and general purpose management. Workload aware management differentiates IWD from its competition, as it can deliver more value for the set of products for which it has context. There is a set of actions that workload aware management tools can do that is normally left to the user by general purpose management tools. This list includes configuring a middleware server to know its hostname/IP address, configuring multiple middleware servers to know of one another, arranging clusters, applying maintenance, and handling elasticity. By handling more of these activities in the automated flow, there are fewer chances for manual errors and inconsistencies to enter a managed environment.
That said, without infinite resource or time, it’s impossible to deliver this context-aware management for everything under the sun. As such, in order to allow IWD to deliver differentiated value AND allow it to handle a customer's entire environment, we offer a mix of workload-aware management and general purpose management.
Me:VMware is a good example of a company active in the cloud space, and they seem to keep a consistent pace of new product delivery. What do you think of their product development focus?
Marc: I think VMware has built a very compelling set of capability in the virtualization space. I think the main difference between VMware's suite and IBM Workload Deployer is the perspective from which the environments are managed. VMware puts the administrator in the position of thinking about infrastructure from the ground up. The administrator is thinking about virtual images, hypervisors, and scripts. In IBM Workload Deployer, we think about things from the perspective of the app, because that's ultimately what the business cares about. By providing a declarative model through which an application can be instantiated and managed, we feel we deliver a deeper value proposition to clients, through workload-aware management.
Me:The 'one tool to do it all' approach is a popular, if not hard to achieve goal. What is your advice to users when it comes to choosing between breadth and depth for cloud management solutions?
Marc: The advantages of a "one tool to do it all" are many: less integration, more uniformity, less complexity. As such, customers will always prefer a single tool when possible. This is why IBM Workload Deployer has focused on not only providing differentiated, deeper value for common use cases but also providing a way to handle the "everything else." As such, my advice to users is not to choose between breadth and depth - use IBM Workload Deployer which offers both.
Me:To close, I'm curious to know where you think we are heading in the cloud market. What do you think users will be most readily adopting over the next one to two years? Where does the cloud industry need the most innovation?
Marc: I think most users are currently looking at the broad picture of cloud computing, and have been adopting primarily in the private cloud realm. There are several reasons for this. One reason is that many customers have a large set of hardware resources which amount to sunk cost that needs to be leveraged. Another reason is around data security concerns in off-premises clouds, and still another reason is around the human factor of comfort, which has taken time to develop around off-premise cloud models. However, businesses have become increasingly comfortable with various sources of outsourcing in recent years, especially in mission critical areas involving very sensitive data. Just look at IBM's Strategic Outsourcing business, which handles entire IT operations for many large businesses. I think that trend will (and really, has already begun to) continue in the area of cloud computing, and will lead to more public and ultimately hybrid cloud computing adoption. In order to get to hybrid cloud computing, I see much of the focus and innovation being associated with data security, workload portability (across private and public, in a seamless fashion), and license transferability between private and public. When this space reaches fruition, clients will be able to enjoy true elastic economics in a computing model that allows a mixture of owning and renting compute resources and software licenses.
Virtual image parts play a huge role in WebSphere CloudBurst. When crafting your own customized patterns, you include anywhere from 1 to n parts from as many different virtual images as is necessary. These parts represent the different node types or personalities within a given Hypervisor Edition image, and form the basis of your pattern. When you deploy a pattern, such as the one pictured below, WebSphere CloudBurst creates a distinct virtual machine for each part.
This means that after deploying the above WebSphere Application Server pattern, you will have four virtual machines comprising your virtual system. This gives you a clean separation of concern by providing a unique container for each of your application environment nodes. This can attribute to performance optimization, increased availability, and much more. However, this approach is not suitable to all use cases. In some scenarios, especially when trying to control costs and increase consolidation, you may want to deploy a multi-node WebSphere Application Server environment within a single virtual machine. Based on what I showed you above, you might think our approach in WebSphere CloudBurst makes this impossible, but you would be overlooking an important component of patterns.
That component is of course the second building block of patterns... script packages. As you probably know, script packages allow you to supply just about any customization you want. In the case that you want a single virtual machine to host a number of WebSphere Application Server nodes, maybe even an entire cell, all you need to do is supply a script package that constructs the necessary nodes during deployment. In fact, you don't even have to write the script package. You can use the free sample in our samples gallery. As seen in the pattern below, you include this script package on a sole deployment manager part in a pattern.
The script script package provides parameters that define the node name, number of custom nodes, and number of web server nodes you want in your cell. During the deployment process, the script takes this information and constructs the cell you define. This includes creating the custom and web servers nodes and federating the custom nodes, thus completing the creation of your WebSphere Application Server cell. In this case, the script package provides deployment flexibility that is sometimes a necessity, and it is just another example of the many degrees of flexibility enabled by the script package design.
I should point out that a part in a pattern does not always map to a single node. For instance, in the case of WebSphere Process Server, there is a part that represents a complete, multi-node golden topology encapsulated within a single virtual machine. However, if you find yourself using images that do not contain these multi-node parts, rest easy knowing script packages provide you the flexibility you need.
The ability to package custom maintenance packages and upload them as emergency fixes is perhaps a lesser known feature of WebSphere CloudBurst, but nevertheless something that's been around since the product's initial release. This is a powerful feature that allows you to build your own fix packages that you can then apply the same way you would use WebSphere CloudBurst to apply a PAK file or fixpack shipped by IBM.
Since IBM is delivering fixes and updates to all of the contents within WebSphere Application Server Hypervisor Edition virtual images (including the OS and IBM software components), you may wonder why you would even want to create your own maintenance packages. One reason would be if you switched out the SUSE Linux operating system shipped with the VMware ESX based images in favor of your own Red Hat operating system. In that case you would be responsible for maintenance to the operating system, and custom maintenance packages would be of interest to you. Another scenario where these custom maintenance packages come in handy would be if you created your own customized images that include non-shipped third-party software in addition to the software shipped in the images. If at some point you have the need to fix or update this software in a running virtual machine, custom maintenance packages provide you the vehicle with which to do just that.
What do these custom maintenance packages look like? In short, they are simply archives or ZIP files. The contents of the archive are largely decided by you, but there is one piece of metadata that is necessary if you want to use WebSphere CloudBurst to apply the maintenance. A file called service.xml is inserted into the root of the archive and tells WebSphere CloudBurst critical information about the custom fix archive. Here's an example of a service.xml file:
Most notably, this metadata tells WebSphere CloudBurst what module or script to invoke to apply the maintenance (Command, this executable is supplied by you), what image versions the fix is applicable to (ImagePrereqs), and the location of the working directory on the virtual machine (Location). In addition to the service.xml file and the executable, you can package up anything else, such as product binaries, which are needed to successfully apply the fix/upgrade/maintenance.
If you haven't noticed, this is an extremely flexible mechanism and can be used for just about anything. I should point out that you can only apply a given fix once per virtual machine, so it's not good for something that you want to run repeatedly against a given machine (check out user-initiated script packages instead). Also, there is a 512MB size limit on the archives. Keep these restrictions in mind when you are deciding how to use custom maintenance packages. If you are interested in learning a bit more about custom maintenance packages or other maintenance techniques, check out this article I co-authored along with Xiao Xing Liang from the IBM SOA Design Center in the China Development Lab.
It's really hard to complain about my work week right now. As I write this blog, I'm sitting in the Congress Center in Düsseldorf, Germany looking out over the Rhine River. As an aside, in Germany it is the Rhein River, and I have a historical connection to this body of water. My surname, Amrhein, translates (loosely) to 'on the Rhein'. It does not take an expert in genealogy to conclude that I have ancestors who at one time or another lived very close to this important German waterway.
Okay, putting the family tree aside for a minute, there is a good reason that I am in Düsseldorf this week. The city, and specifically the Congress Center, is playing host to the IBM European WebSphere Technical Conference. I am here presenting sessions that include a WebSphere CloudBurst overview, a WebSphere CloudBurst hands-on lab, and an up-close look at one of our internal team's use of the appliance. I have done each of these sessions once so far, and attendance was great, audience participation high, and feedback forthcoming. I am hearing and seeing the same thing in other sessions, which is of course, ideal for us presenters.
Now, to focus in on WebSphere CloudBurst for a bit, it seems that I am hearing a recurring question this week from the mostly European audience: "Why is WebSphere CloudBurst delivered as an appliance?" I am sure that I addressed this question in a previous blog post, but I believe it bears revisiting. There are various reasons I could give for the appliance form factor, but I like to distill all of that down into three major reasons: Consumability, Performance, and Security.
From a solution consumability perspective, nothing beats the appliance approach. WebSphere CloudBurst is an integrated hardware and software solution that delivers a specific set of function. You do not have to install software, procure and maintain storage for resources on the appliance (images, patterns, scripts, etc.), and maintain software components over time. You simply drop the appliance in to your data center, perform a one-time initialization, hook it up to the network, and you are ready to start leveraging WebSphere CloudBurst to build out your private cloud. While there is definitely work to setup the cloud infrastructure that WebSphere CloudBurst deploys environments to, we can completely eliminate a significant portion of solution implementation lead time by delivering everything you need in the appliance.
The performance benefits of an appliance approach are a natural result of building an integrated hardware and software stack. Design and development teams provide optimizations in both the hardware and software based on the fact that both the hardware and software have intimate knowledge of each other's design. In other words, this is not a 'least common denominator' tuning approach. Rather, the integrated design leads to enhanced performance for the specific set of functionality provided by WebSphere CloudBurst.
Finally, appliances enable us to deliver a very hardened, secure device. We provide private key encryption of every resource stored on the appliance. That private key is unique to each appliance and cannot be modified. In addition, the physical casing is tamper-resistant. If someone removes the casing, a 'Get Smart' style kill switch puts the appliance in a dormant state. You must send the appliance to IBM so we can reset it before further use, thus providing an additional layer of physical protection on top of the encryption. These security features, plus more, like a shield that prevents anyone from executing code on the appliance, come right out of the box and require no end-user configuration activity. In this way, you can simply focus on leveraging the user security and access controls provided by WebSphere CloudBurst.
If you had any questions on the rationale behind the appliance form factor of WebSphere CloudBurst, I hope this helps. I am off for now... back to the conference and the wonderful city of Düsseldorf.
I was at a customer meeting the other day, and someone asked me if they could query WebSphere CloudBurst for an inventory of all of their virtual system deployments. This person was of course aware that he could go to the web console and very quickly view all of the virtual systems. What he wanted though was something that he could run to generate a report that contained all of this information. For a purpose like this, harnessing the WebSphere CloudBurst CLI is exactly the way to go.
I thought I'd write a simple CLI script that provides an example of how you could do this.
from datetime import datetime
outFile.write("WebSphere CloudBurst Virtual System Inventory\n")
outFile.write("Total virtual systems: " + str(len(cloudburst.virtualsystems)))
def writeVSDetails(outFile, virtualSystem):
outFile.write("\tVirtual system name: " + virtualSystem.name)
outFile.write("\tCreated from pattern: " + virtualSystem.pattern.name)
outFile.write("\tVirtual system status: " + virtualSystem.currentstatus_text)
created = datetime.fromtimestamp(virtualSystem.created)
outFile.write("\tVirtual system creation date: " + created.strftime("%B %d, %Y %H:%M:%S"))
outFile.write("\tTotal virtual machines: " + str(len(virtualSystem.virtualmachines)))
def writeVMDetails(outFile, virtualMachine):
outFile.write("\t\tVirtual machine name: " + virtualMachine.name)
outFile.write("\t\tVirtual machine display name: " + virtualMachine.displayname)
outFile.write("\t\tCreated from image: " + virtualMachine.virtualimage.name)
outFile.write("\t\tVirtual machine hypervisor: " + virtualMachine.hypervisor.name + " | " + virtualMachine.hypervisor.address)
outFile.write("\t\tVirtual machine IP address: " + virtualMachine.ip.ipaddress)
outFileLoc = sys.argv
outFile = open(outFileLoc, 'w')
for virtualSystem in cloudburst.virtualsystems:
for virtualMachine in virtualSystem.virtualmachines:
As a result of invoking this script using the CLI's batch mode, content is written to the file location supplied by the caller.
WebSphere CloudBurst Virtual System Inventory
Total virtual systems: 3
Virtual system name: Single server
Created from pattern: WebSphere single server
Virtual system status: Started
Virtual system creation date: January 15, 2010 16:37:20
Total virtual machines: 1
Virtual machine name: Standalone 0
Virtual machine display name: Single server cbvm-110 default
Created from image: WebSphere Application Server 126.96.36.199
Virtual machine hypervisor: Ruth ESX | https://<hypervisor_host>/sdk
Virtual machine IP address: <ip_address>
Virtual system name: Development WAS Cluster
Created from pattern: Custom WAS Cluster - Development
Virtual system status: Started
Virtual system creation date: January 18, 2010 14:08:46
Total virtual machines: 2
Virtual machine name: DMGR 0
Virtual machine display name: Development WAS Cluster cbvm-112 dmgr
Created from image: WebSphere Application Server 188.8.131.52
Virtual machine hypervisor: Ruth ESX | https://<hypervisor_host>/sdk
Virtual machine IP address: <ip_address>
Virtual machine name: Custom Node 1
Virtual machine display name: Development WAS Cluster cbvm-111 custom
Created from image: WebSphere Application Server 184.108.40.206
Virtual machine hypervisor: Ruth ESX | https://<hypervisor_host>/sdk
Virtual machine IP address: <ip_address>
Virtual system name: DB2 for development use
Created from pattern: DB2
Virtual system status: Started
Virtual system creation date: January 18, 2010 14:09:58
Total virtual machines: 1
Virtual machine name: DB2 Enterprise Server 32bit Trial 0
Virtual machine display name: DB2 for development use cbvm-113
Created from image: DB2 Enterprise 220.127.116.11 32-bit Trial
Virtual machine hypervisor: Ruth ESX | https://<hypervisor_host>/sdk
Virtual machine IP address: <ip_address>
I withheld IP addresses and host names above for obvious reasons, but if you ran the script against your environment you would see actual host name and IP address values. The script above is written once, and it can be subsequently run anytime you want an inventory of virtual systems running in your WebSphere CloudBurst cloud. There's other information available for virtual systems and virtual machines that I didn't show here, and you can retrieve it if necessary for your inventory report. In addition, I chose to print this information as regular text in a file supplied by the caller, but you might choose to generate the report in another format including XML, JSON, or anything else for that matter.
-- Dustin Amrhein
p.s. As with any sample code or script I provide here, the above is only a sample and offered as-is.
I write a lot about WebSphere CloudBurst script packages. Typically, I write about what they are, how to create them, and even provide some samples from time to time. I find that most of the time I'm either writing or talking about script packages from the standpoint that they allow you to automate the delivery of customizations to environments you deploy with WebSphere CloudBurst. More specifically, I usually explain how you can include these script packages in your patterns to ensure that your custom scripts execute as part of every pattern deployment. The truth is, that is not the whole story. In fact, it's only 1/3 of the story.
In WebSphere CloudBurst, when you define a script package you also define its execution mode. The execution mode can be one of three values, and it indicates the invocation time for the script. The default value is at virtual system creation, and that tells WebSphere CloudBurst to automatically invoke the script as part of the deployment process. This seems to be the most commonly used execution mode, and in the original version of WebSphere CloudBurst it was the only available mode (which probably attributes to why I only usually tell 1/3 of the story here). As you may expect, there is a wide range of usage scenarios for this class of script packages including installing applications, activating monitoring agents, registering cells with an externally managed DNS server, and much more.
If you are like me (and many humans), you enjoy and actually expect symmetry. In that regard, it probably comes as no surprise that there is a script package execution mode called at virtual system deletion. As the name indicates, this class of script packages executes as an automatic part of the virtual system deletion process. When a user tells WebSphere CloudBurst to remove a virtual system, before it shuts down the machines in the system, it will run each script package marked to execute at virtual system deletion. Typical use cases for these scripts include removing information about the cell from externally managed DNS servers, freeing up connections with external systems, and other external 'clean up' activities.
So this leaves the final execution mode for script packages, the when I initiate it mode to be precise. This class of script packages executes when explicitly triggered by a user. In the virtual machine detail section for a deployed virtual system, you can see a list of user-initiated script packages for a given machine. There is a start button by each of the user-initiated script packages that allows you to invoke the script when, and as many times as you need to. While these script packages have many different use cases, the most common use case is to deploy application updates. Users build these application update scripts, attach them to a pattern, and invoke them whenever they want to deliver an updated application into their already deployed environment.
WebSphere CloudBurst script packages are one of the main vehicles for delivering your customizations to your cloud environments. The three execution modes mentioned above allow you to determine when the right time to deliver those customizations is.
If you've read anything I've written about WebSphere CloudBurst up to this point you know all about patterns. Using the appliance you can easily and quickly build, deploy, and manage these representations of your middleware application environments. Today, I want to focus in on the deployment piece in particular and take a look at how you can easily automate this process.
You can use the WebSphere CloudBurst web console to deploy patterns, and when doing so you can even schedule the deployment to happen at a later date. This scheduling capability certainly gets you on the road to an automated deployment process, but what if you want to take it one step further and eliminate the need for someone to login and manually move around the web console to schedule automated deployments? In this case, you can use either the CLI or the REST interface that WebSphere CloudBurst offers.
In this post I thought I'd take a look at using the CLI interface in order to set the stage for some nice automation around pattern deployment. It starts out with a properties file that provides details about my deployment. This includes the cloud to deploy to, the pattern to deploy, password information, and the time at which the virtual system should start.
SYSTEM_NAME_PREFIX=New App Development
TARGET_CLOUD=Default ESX group
TARGET_PATTERN=WebSphere single server
Imagine that the properties file above gets written as the result of some other action, such as the completion of your application's build process. With the properties file in place, and I'll point out that your properties file can and probably will be more robust than above, let's move on to the code that handles the deployment process based on the information in said file. First, we have a small amount of CLI code to retrieve and parse the input data (I omitted the straight-forward properties retrieval for space):
from datetime import datetime, timedelta
from java.util import Properties
from java.io import FileInputStream
// read in and retrieve properties using java.util.Properties API (i.e. props.getProperty('DEPLOYMENT_DATE'))
parsedParts = deploymentDate.split(" ")
systemName = systemName + "_" + deploymentDate
dateParts = parsedParts.split("/")
timeParts = parsedParts.split(":")
monthPart = int(dateParts)
dayPart = int(dateParts)
yearPart = int(dateParts)
hourPart = int(timeParts)
minutePart = int(timeParts)
Next is the code that actually schedules the pattern deployment:
First we get the desired deployment time and current time as datetime objects. After that, assuming the desired deployment time has not already elapsed, we calculate the difference between the desired deployment time and current time. This difference, in seconds, is then added to the result of the time.time() value to come up with a start time. After that is done, we simply retrieve the cloud that was indicated in the properties file, and then we call the runInCloud method for the pattern indicated. When calling the runInCloud method we supply the name of the virtual system that will be created, password information, and the start time we calculated earlier. As a result of this method call, a task will be generated in the target WebSphere CloudBurst Appliance and the virtual system will be started at the specified time. This will happen in an automated fashion with no human intervention required.
That's really all there is to automating the pattern deployment process using the CLI. In a more complete, end-to-end scenario you may envision the completion of one process, such as an application build process mentioned above, result in the writing of the properties file and in turn the call into the CLI to deploy a pattern. As always, feel free to send me any comments or questions.
It's about the time of year when we all look back and try to determine exactly how we spent the past twelve months. Whether we do it because we have to as part of year-end job reviews or because we like to take stock in what we've done and figure out where to improve next year, it's a time for reflection and recall. For me, this exercise made me take a look at various things we have done to deliver WebSphere CloudBurst technical collateral (articles, demos, blogs, etc.) in 2009.
For all practical purposes, our mission and efforts for such technical collateral for WebSphere CloudBurst started when it was announced at Impact in May of this year. Though there was certainly some preparatory work being done on this front, there was nothing we could really push to the public until after the announcement, and in some cases even after the appliance's release in June. Given that most of the content was produced over a six month stretch, I really think we put forth a strong effort, and I hope that this technical material has helped to both raise awareness of and educate users on the WebSphere CloudBurst Appliance.
Seeing as I already went back and rounded up this content, I thought I'd provide you a centralized look at the information. To start, I accounted for the articles that we published to the IBM developerWorks site over the six month stretch. All together I counted 8 articles and a special column entry:
As you can see the articles cover quite a bit of content and range from general level overview articles to technical in-depth "how-to" style articles. In general they seem to have been received well with over 26,000 views to this point. Our goal is to keep the pace up for 2010, and we already have a few articles on our plate for early in the new year (including an overview of what's new in WebSphere CloudBurst 1.1).
Another main medium we utilized to spread the word about WebSphere CloudBurst was YouTube. On our YouTube channel at http://youtube.com/websphereclouds, we currently have 17 different videos that demonstrate how to use certain features of the WebSphere CloudBurst Appliance. Though I think each demo provides value depending on exactly what a viewer is looking for, 3 of them really stick out for me.
Check out our videos if you get a chance. We've made an effort to keep them as short as possible while still providing value to viewers.
We have some WebSphere CloudBurst content spread around other places as well including this blog and my personal blog. Over the next few weeks we'll be taking a look at what worked and didn't work with respect to getting information out to the public. Of course at any time we very much appreciate your feedback on how you like to see content delivered because you are our target audience! If you have a comment, idea, or suggestion, leave a comment on the blog or send me a tweet to @WebSphereClouds.
When it comes to managing users and user groups within WebSphere CloudBurst, you can choose to manage all aspects of those resources within the appliance. Mainly this means that you can define and store user information (including login passwords) within the appliance, and you can define and maintain user groups and their associated membership list on the appliance. While you can do this and be sure that your information is extremely secure, you may instead want to integrate with an existing LDAP server that has some of this user and user group data. WebSphere CloudBurst certainly allows you to integrate with LDAP servers, but what does that mean for you?
For starters, when you integrate WebSphere CloudBurst with an LDAP server and enable the LDAP authentication feature, you no longer specify password information when defining users of the appliance. When users login, the password they specify will be authenticated against information stored in the LDAP server. Naturally, if you add a new WebSphere CloudBurst user with LDAP authentication enabled, that user must be defined in the LDAP server. Otherwise, WebSphere CloudBurst will prevent you from adding the user because it has no way to authenticate that person.
From a user groups standpoint, integrating with LDAP means you can no longer modify user group membership. User membership in groups is determined by information in the LDAP server. As a result, the same rule concerning adding new users applies when adding new user groups: You cannot define new user groups that do not exist in the LDAP server.
If you want to take a look at what LDAP integration looks like with WebSphere CloudBurst, I put together a short video. Let me know what you think.
If you frequently find yourself setting up and tearing down application environments that run on offerings from the WebSphere portfolio (like WebSphere Application Server or WebSphere Process Server), I have little doubt that you see the benefit of WebSphere CloudBurst. The appliance allows you to setup these environments with unprecedented speed and extreme simplicity. In fact, WebSphere CloudBurst makes it so simple and fast to setup these environments, it would be surprising if you did not spin up more WebSphere application environments with WebSphere CloudBurst than you did before your adoption of the appliance. Soon, you will find yourself faced with another challenge: that of managing and governing an increasingly growing ecosystem of your application environments.
From the beginning, WebSphere CloudBurst focused on the complete lifecycle for WebSphere application environments in an on-premise cloud. Therefore, in addition to easily creating and deploying these environments, the appliance delivers many features that help you manage and govern the dispensed virtual systems. This includes capabilities such as usage monitoring, fix and upgrade application, and virtual system state management. In the recently announced WebSphere CloudBurst 2.0, management capabilities go a step further, and now you can manage software license usage for your on-premise cloud.
What does it mean to be able to manage your software licenses? Well, in the new version of the appliance (firmware released planned for June 18th), as you dispense environments, WebSphere CloudBurst will keep track of the PVUs you are consuming for the particular IBM software you are instantiating. In doing this, it accounts for the physical machine architecture on which the supporting hypervisor sits, and it takes into account the IBM subcapacity/virtualization licensing policy. This means you can get an accurate view of your PVU usage at any point, and the appliance can produce a highwater mark report for any product over a date period you specify. This is license counting made easy!
In addition to simply tracking your PVU usage, you can optionally configure enforcement behavior. Enforcement behavior tells the appliance what to do when you exceed your PVU threshold for a particular product. You have three basic options: Ignore, Warn, Enforce. In Ignore mode, nothing happens when you exceed your PVU entitlement for a given product. Deployments that use those products continue to deploy as usual. In Warn mode, deployments for products for which you have exceeded your PVU entitlement continue as usual, but appliance administrators receive an email warning them of the situation. Lastly, in Enforce mode deployments that will put you over your PVU threshold for a given product simply fail. This prevents you or deployers using your appliance from overstepping your entitlement.
The software license management features in WebSphere CloudBurst 2.0 really add to the overall management capabilities of the appliance. I want to be sure to reiterate that the configuration of enforcement behavior, specifically the Warn and Enforce modes, is optional. It is not required from IBM. The software license management capabilities delivered in WebSphere CloudBurst 2.0 are purely meant to enhance your capability to manage and govern environments in your on-premise cloud. If you are interested in seeing this in action, check out this short video.
Over the past several months industry focus on cloud computing seems to have only intensified. Within IBM and for the purposes of this blog, WebSphere, there have been several announcements and offerings that indicate our commitment and belief in the cloud computing approach.
To further highlight WebSphere's focus and offerings in the cloud computing realm, we are embarking on a "WebSphere in the Clouds" campaign during the months of September and October. Our intent is to virtually deliver information about our cloud strategy and offerings directly from the experts to you, our WebSphere users.
The event will be kicked off by WebSphere's Director of Product Management, Kareem Yusuf, on September 23rd from 9-10 EDT. Kareem will talk about cloud computing in the enterprise, and its unique relationship to SOA thoughts and principles. In addition, he'll give an overview of what WebSphere has been doing in the cloud computing space. This will be followed by sessions from technical experts that detail WebSphere offerings in both the public and private clouds, as well as sessions that discuss enablers of application and application infrastructure elasticity.
To find out more about the "WebSphere in the Clouds" campaign, you can check out the main announcement page. To sign up for the series of virtual events visit the registration page. We hope you will join us for the series of webcasts to learn all about WebSphere's work in the clouds.
The concepts that govern users and user groups in WebSphere CloudBurst are fairly basic, but I get asked about them enough that I believe they warrant a short discussion. First things first, you can define users in WebSphere CloudBurst and optionally define user groups to assemble users into logical collections. For both users and user groups, you can assign roles that define the actions a particular user or group of users can take using the appliance.
All of that is straight forward, but it can get a bit tricky once we start considering the effects of user permissions when managing at the user group level. The basic premise is that when a user belongs to a group or groups, the user's effective permissions are a sum of the permissions to all of the groups to which they belong. While that is easy to say, and maybe even to understand, I feel like an example always helps.
Consider that we have a single user WCAGuy that belongs to the PatternAuthors, ContentCreators, and CloudAdmins groups. The permissions for those groups are as follows:
PatternAuthors: Users in this group have permission to create and deploy patterns
ContentCreators: Users in this group have permission to create catalog content as well as create and deploy patterns
CloudAdmins: Users in this group have permission to administer the cloud, create catalog content, and create and deploy patterns
Naturally then, it follows that the WCAGuy user can administer the cloud, create catalog content, create patterns, and deploy patterns. So then, what happens if we remove the WCAGuy user from the CloudAdmins user group? Well, as you may expect, there is an update to the user's permissions. The WCAUser user can no longer administer the cloud, but they can still create catalog content, create patterns, and deploy patterns (owing to their membership in the other two groups). Similarly, if we next removed the WCAGuy user from the ContentCreators group, then the user would retain only the permission to create and deploy patterns.
Just one more thing, let's talk about what happens when I remove a user from a group and they no longer belong to any groups. Consider that I created the WCAGuy user with the permission to create catalog content as well as create and deploy patterns. Next, I added the user to the CloudAdmins group, meaning the user now has the permission to administer the cloud. I promptly decide that the user has no business with those permissions, so I remove the user from the CloudAdmins group. What happens? The user retains the permission set of the last group to which they belonged. In this case, that means the WCAGuy user retains cloud administration rights. I have to update the user's permission set if I want to take that right away, but in this case, it will not automatically disappear upon removing them from the CloudAdmins group.
I hope this helps clear up any ambiguity you may have had concerning users, user groups, and permission sets in WebSphere CloudBurst.
I’m going to take a different approach this week in the blog. Instead of me telling you about some of the features or uses of WebSphere CloudBurst, I thought I would catch up with someone using the product everyday, WebSphere Test Architect Robbie Minshall. Robbie is responsible for a team of testers that harness a lab of over 2,000 physical machines to put our WebSphere Application Server product through some pretty rigorous testing. Toward the beginning of this year Robbie’s team started to leverage the WebSphere CloudBurst Appliance in order to create the WebSphere Application Server environments needed for their testing.
Robbie, can you tell us a little bit about what the WebSphere Application Server test efforts entail?
In WebSphere Application Server development and test we have two primary scenarios. The first is making sure that developers have rapid access to code, test cases and server topologies so that they can write code, test cases and then execute test scenarios on meaningful topologies. The second scenario is an automated daily regression where in response to a build, we provision a massive amount of WebSphere Application Server topologies and execute our automated regression tests.
Previously we have supported these scenarios through the deployment of the Tivoli Provisioning Manager for operating system provisioning, some applications for checking out environments, and then a lot of automation scripts for the silent install and configuration of WebSphere Application Server cells.
Given those scenarios and the existing solution, what are your motivations for setting up a private cloud using WebSphere CloudBurst Appliance?
We are supporting these scenarios through a pretty complicated combination of technologies. These include silent WAS install scripts, wsadmin configuration scripts, a custom hardware leasing application and the utilization of Tivoli Provisioning Manager for OS Provisioning. This solution is working very well for us though as always we are looking for areas to improve, opportunities to simplify and to reduce our dependency on investment in our custom automation scripts. Mainly, there were 3 areas where we wanted to improve our framework: Availability, Utilization and Management. This is why we started looking to the WebSphere CloudBurst Appliance.
Can you expand a bit on what you are looking for in those three areas?
The first focus area we have is availability of environments. We really wanted to lower the entry requirement for the skills and education necessary to get a development or test environment. Setting up these environments has just been too hard, too time consuming, and too error prone. Using WebSphere CloudBurst we can provide an easy push button solution for developers to get on-demand access to the topologies they need.
The second area we are looking for significant improvements on is hardware utilization. Our budgets are tight and in our native automation pools we are only using between 6-12% of the available physical resources. In order to improve this we were looking at leveraging virtualization. WebSphere CloudBurst offers the classic benefit of virtualization with the nice additions of optimized WebSphere Application Server placement and really good topology and pattern management. In our initial experiments we were able to push the hardware utilization up to 90% of physical capacity and consistently were leveraging around 70% of our physical capacity.
Finally we are looking to improve and simplify our management of physical resources and automation. We work in a lot of small agile teams and organizational priorities change from iteration to iteration. Not only does WebSphere CloudBurst allow us to maintain a catalog of topologies or patterns for releases but it also allows us to adjust physical resource allocation to teams through the use of sub clouds or cloud groups.
Basically we felt that WebSphere CloudBurst would improve the availability of application environments, enhance automation, and improve hardware utilization all with very low physical and administrative costs.
What were some of the challenges involved with getting a cloud up and running in your test department?
One of our challenges seems like it would be common to many scenarios, especially in today’s world. Our budget for new hardware to build out our cloud infrastructure was initially very limited. Most cloud infrastructure designs depict very ideal hardware scenarios including SANs, large multicore machines, and private and public networks within a dedicated lab. Quite frankly we did not have the budget to create this from scratch. It was important for us to demonstrate value and data to warrant future investment in dedicated infrastructure. After some performance comparisons we were very happily surprised to see that we could leverage our existing mixed hardware within a distributed cloud. The performance of application environments dispensed by WebSphere CloudBurst on many small existing boxes in comparison to large multicore machines with a SAN was very comparable. This allows us to leverage existing hardware, with minimal investment all the while demonstrating the value and efficiencies of cloud computing. That data in turn has allowed us to obtain new dedicated hardware to iteratively build up a larger lab specifically for use with WebSphere CloudBurst.
Specifically with WebSphere CloudBurst, are there any tips/hints you would offer users getting started with the appliance?
Sure. First, we quickly realized as we added hypervisors to our WebSphere CloudBurst setup it was critical to have someone with network knowledge on hand. This is because the hypervisors came from various sections of our lab, and we really needed people with knowledge of how the network operated in those different sections. Once we had the right people we were able to setup WebSphere CloudBurst and deploy patterns within an hour and a half.
Moving forward we continued to have challenges as we dynamically moved systems between our native hardware pool and our cloud. Occasionally the WebSphere CloudBurst administrator would move a system into the cloud but incorrectly configure the network or storage information. This lead to some misconfigured hypervisors polluting our cloud. We overcame this, quite simply and satisfactorily I may add, by creating some simple WebSphere CloudBurst CLI scripts which add the hypervisors, test them individually, by carrying out a small deployment to that hypervisor, and then move the correctly configured hypervisors into the cloud after verifying success. Misconfigured hypervisors go into a pool for problem determination. This has allowed us to maintain a clean cloud, and we are able to dynamically move our hardware in and out of the cloud to meet our business objectives.
We also use the WebSphere CloudBurst CLI to prime the cloud so to speak. Before using a given hypervisor in our cloud, we execute scripts that ensure each unique virtual image in our catalog has been deployed to each of our hypervisors at least once. When the image is first deployed to a hypervisor, a cache is created on the hypervisor side of the connection, thus meaning subsequent deployments do not require the entire image to be transferred over the wire. This gives us consistent and fast deployment times once we are using a hypervisor in our cloud.
I would assume that like many applications deployed on WebSphere Application Server, your team’s applications have several external dependencies. Some of these dependencies won’t necessarily be in the cloud, so how did you handle this?
You’re right about the external dependencies. Our applications and test cases run on the WebSphere Application Server but are dependent upon many external resources such as databases, LDAP servers, external web services etc. WebSphere CloudBurst allows us to deploy WAS topologies in a very dynamic and configurable way but the 1.0.1 version does not allow us to deploy these external resources in the same manner. This was overcome by using script packages in our patterns. These script packages allow us to associate our test applications with various patterns we have defined. The script package definition also allows us to pass in parameters to the execution of our scripts. We supply these parameter values during deploy time, and these values are used to convey the name or location of various external resources. The scripts that install our applications can access these values and ensure the application is properly integrated with the set of resources not managed by the appliance.
What is your team looking to do next with WebSphere CloudBurst and their private cloud?
The next challenge on our plate is to keep up with the demand of our expanding cloud and to develop a more dynamic relationship between our native pools and our cloud using the Tivoli Provisioning Manager. These are fun challenges to have and we look forward to sharing our progress.
I'm glad I got to spend some time with Robbie to glean some insight into their work and progress with WebSphere CloudBurst. I hope this information was useful to you. It's always nice to hear about a product from practitioners who can give you hints, tips, gotchas, and other useful information. Be sure to let me know if you have any questions about what Robbie and his team are doing with WebSphere CloudBurst.
For the next installment of this series of FAQs, let's move from product positioning and integration, square into the land of operational procedure. For this post, we will consider you are getting ready to deploy a pattern based on the WebSphere Application Server Hypervisor Edition. During the deployment process, you provide configuration information, which includes a password for a user named virtuser.
You read the documentation, and you understand that virtuser is both an operating system user and the user that WebSphere CloudBurst configures as the primary administrative user for WebSphere Application Server. Naturally, this user owns the WebSphere Application Server processes that run in the virtual machine. While it is convenient that this is all pre-configured for you, you want to know one thing: "Can I define a user besides virtuser?"
It certainly would not be the first time this question came up. The short answer to this is yes, but there are of course caveats. You can define another user and have that user own the WebSphere Application Server processes, but you cannot completely remove the virtuser user, nor should you remove virtuser as the primary administrative user. The reason for this is that WebSphere CloudBurst relies on virtuser when it carries out certain actions such as applying maintenance, applying fixes, or otherwise interacting with the WebSphere Application Server environment.
All that being said, I recently put together a script package that allows you to utilize a user other than virtuser. I hope to put the script package in our samples gallery soon, but here's a basic overview of using the script package and what it does:
Attach the script package to all parts in a pattern that contain a WebSphere Application Server process.
Deploy the pattern and provide the necessary parameter values. These include the name of the new user, a password, a common name, and a surname. The last two bits are necessary when creating a new administrative user in WebSphere Application Server.
During deployment, the script package first creates a new OS user with the specified password.
The script adds the new user to the existing OS users group.
The script creates a new WebSphere Application Server user with the same username and password and grants administrative privileges to the user.
The script shuts down the WebSphere Application Server processes.
The script changes the runAsUser value for all servers to the empty string and sets the runAsGroup value for those servers to users. This allows members of the OS users group to start the WebSphere Application Server process.
The script starts the WebSphere Application Server processes.
There are a few other activities in the script, but that should give you a basic overview. Again, note that the script does not remove the virtuser user or change that user's OS or WebSphere Application Server permissions in anyway. I would also point out that if you use WebSphere CloudBurst to apply maintenance to the WebSphere Application Server environment, it will do so as virtuser and it will restart processes as virtuser, so plan accordingly.
I hope this sheds some light on a very common question. I hope to get the sample up soon, and as always let me know if you have any questions.