When we talk about the WebSphere Application Server Hypervisor Edition, we often get a lot of questions about whether or not SUSE Linux is the only flavor of the Linux operating system that we support. The short answer to that question is no.
While it is true that we only deliver the WebSphere Application Server Hypervisor Edition with a SUSE Linux operating system, we will support the use of the virtual image packaging with Red Hat Enterprise Linux as the base operating system. The basic process consists of creating a virtual machine disk based off of a suitable Red Hat install, altering the OVF file in WebSphere Application Server Hypervisor Edition to reference this virtual disk instead of the SUSE virtual disk, and then packaging a new OVA file that contains all the same WebSphere virtual disks (profiles, binaries, IBM HTTP Server) but swaps out the Red Hat virtual disk for the SUSE virtual disk. We have done this many times in both the lab and field, and we offer services to users who need help in creating the image.
Customers often ask if there is any difference in using Red Hat versus SUSE Linux. The answer is, of course, yes and no. The answer is yes in that users must bring their own licenses of Red Hat (SUSE Linux licenses are included in the WebSphere Application Server Hypervisor Edition), and users must support and maintain the Red Hat operating system on their own. However, once the image is built, there is absolutely no difference in the use of that image within WebSphere CloudBurst.
Once built, users upload the image into their WebSphere CloudBurst catalog and it is available for use in pattern building just like any other image. I mentioned that users are responsible for updating and maintaining the image, well users can use WebSphere CloudBurst to create these updated images. When patches or updates are ready for the Red Hat operating system, the Extend/Capture facility available for images in WebSphere CloudBurst can be used to create a new custom Red Hat operating system with your desired fixes. This is all done without ever having to worry about actually recreating and repackaging the image again.
I know seeing is believing, so with respect to the "sameness" of using a Red Hat version of the WebSphere Application Server Hypervisor Edition within WebSphere CloudBurst, I've created a short demo you can watch here. As always, let us know what you think and send any questions our way.
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.
When I talk with WebSphere CloudBurst users, the topic of custom virtual images comes up frequently. In some cases they simply want to customize a shipped IBM Hypervisor Edition, and in other cases they want to create a completely custom image. Creating a customized version of an IBM Hypervisor Edition is relatively easy since we give you extend & capture in WebSphere CloudBurst. Creating a completely custom image has historically been a bit tougher, mostly owing ot the fact that there was not a standard tool or process for image assembly. I am happy to say that today's publication of the IBM Image Construction and Composition Tool changes all that.
Watch a demo of the IBM Image Construction and Composition Tool
The primary purpose of the Image Construction and Composition Tool is to enable a modular approach to virtual image construction, while taking into account the typical division of responsibilities within an organization. The tool allows the right people within an organization to contribute their specialized knowledge as appropriate to the virtual image creation process. This means OS teams can handle the OS and software teams can handle the appropriate software. A separate image builder can then use both OS and software components to meet the needs of users within the organization. Best of all, the image builder does not need intimate knowledge of how to install or configure any of the components in the image. They simply need to know which OS and software components to use.
When using the Image Construction and Composition Tool, you start by defining the base operating system you wish to use for your images. You can do this by importing an existing virtual image with an OS already installed, providing an ISO for the OS, or pointing to a base OS image on the IBM Cloud. The bottom line is that you have necessary flexibility to start with your certified or ‘golden’ operating system build. Once you have the base OS image defined in the Image Construction and Composition Tool, you can start defining custom software for use in the images you will compose.
In the tool, bundles represent the software you wish to install within a virtual image. The definition of a bundle contains two major parts: Installation and Configuration. The installation component of a bundle tells the Image Construction and Composition Tool how to install your software into the virtual image. You provide a script or set of scripts that install the necessary components into your image, and you direct the tool to call these scripts. These tasks run once during the initial creation of the virtual image, thus allowing you to capture large binaries, long-running installation tasks, or other necessary actions directly into your image.
The configuration section of a bundle defines actions that configure the software installed into the image. Like with the installation tasks, you provide a script or set of scripts for configuration tasks. Unlike installation tasks that run exactly once, configuration scripts become part of the image’s activation framework and as such, run during each image deployment. Using the tool, you can define input parameters for configuration scripts and optionally expose them so that users can provide values for the parameters at image deploy-time. Configuration tasks are important in providing flexibility that allows users to leverage a single virtual image for a number of different deployment scenarios.
Once you have your base OS image and one or more bundles defined in the Image Construction and Composition Tool, you can compose a virtual image. To compose a virtual image, you extend the base OS image and add any number of bundles into the new image. A base OS image plus a set of bundles defines a unique image.
After you define the image you want to construct, you initiate a synchronize action in the Image Construction and Composition Tool. When you start the synchronize action, the tool first creates a virtual machine in either a VMware or IBM Cloud environment (based on how you configured the tool). Next, the installation tasks of each bundle you included in the virtual image run to install the required software. Finally, the tool copies the configuration scripts from each bundle into the virtual machine and adds them to the image’s activation framework. This ensures the automatic invocation of all configuration scripts during subsequent image deployments.
Once the image is in the synchronized state, you can capture it. Capturing the image results in the creation of a virtual image based on the state of the synchronized virtual machine. The tool also automates the generation of metadata that becomes part of the virtual image package. When the capture of the virtual image completes, you can export it from the Image Construction and Composition Tool and deploy it using WebSphere CloudBurst, Tivoli Provisioning Manager, or the IBM Cloud.
I am excited for users to get their hands on the Image Construction and Composition Tool. I believe it represents the first big step in helping users to design and construct more sustainable virtual images. Did I mention it is completely free to download and use? Visit the Image Construction and Composition Tool website for more details and a download link. I look forward to your comments and feedback.
One of the things I haven't written about much here is how the WebSphere CloudBurst Appliance integrates with other IBM software solutions. One of those interesting integration scenarios, and one I think is particularly useful for developers, involves Rational Build Forge.
Very simply put, Rational Build Forge is an adaptive execution framework that allows users to define completely automated workflows for just about any purpose. These workflows are represented as projects that contain a discrete number of steps. When looking at Rational Build Forge through the software assembly prism, the offering allows users to fully automate and govern the process of building, assembling, and delivering software into an application environment.
Now, on to the integration of WebSphere CloudBurst and Rational Build Forge. Users can build custom patterns in WebSphere CloudBurst that include a special script package (which I'll eventually provide a link to from here). This script package provides the glue between the deployment process in WebSphere CloudBurst and Rational Build Forge. When deploying a WebSphere CloudBurst pattern that contains this script package, users provide the name of a Rational Build Forge project as well as information about the Rational Build Forge server on which the project is defined.
Once the necessary information is supplied, the deployment process gets underway. Toward the end of the deployment, like all other scripts included in patterns, the special Rational Build Forge script is invoked. This results in the project specified during deployment being executed on the virtual machine created by WebSphere CloudBurst.
Because the Rational Build Forge project executes on a virtual machine setup by WebSphere CloudBurst, the individual steps of the project can very easily access the WebSphere Application Server environment. Thus, the Rational Build Forge project could very easily contain steps to build, package, and deploy an application into the WebSphere Application Server cell. The result is a fully automated process that includes everything from standing up the application environment to delivering applications into that environment.
I put together a short demonstration of this integration, and you can take a look at it here. As always, please let us know if you have any questions or comments. Your feedback is much appreciated!
When one uses IBM Workload Deployer (previously WebSphere CloudBurst) to deploy a virtual system pattern, they benefit from a completely automated deployment process. The automation includes the creation and placement of virtual machines, injection of IP addresses, initiation of internal processes, and invocation of included scripts. Most of these processes are straightforward and require little more than a brief overview. However, the placement of virtual machines stands out, and it's inner workings are the subject of quite a few questions when I discuss the appliance. With that in mind, I thought I would provide a little more information on how the placement algorithm in IBM Workload Deployer works.
The placement subsystem in IBM Workload Deployer considers three primary elements: compute resource, availability, and license optimization. Compute resource availability is the gating factor for placement. That means that IBM Workload Deployer first looks at the available CPU, memory, and storage resource in the collection of hypervisors making up the cloud group(s) you are targeting for deployment. If a particular hypervisor cannot provide enough resource based on the amount you requested for your deployment, then it is automatically taken out of the eligible hosts pool. It is important to note that IBM Workload Deployer will overcommit CPU, and it will overcommit storage if you direct it to do so. It will not overcommit memory because that could severely degrade the performance of the application(s) running in the virtual machines.
After choosing the pool of hypervisors that are capable of hosting the virtual machines in your deployment from a compute resource perspective, the appliance then considers high availability. To better understand this particular placement stage, let's consider an example. Consider you are deploying a pattern based on WebSphere Application Server Hypervisor Edition and it contains two custom node parts. It is conceivable, and in fact likely, that these two custom node parts will host members of the same cluster, and thus the two nodes will support the same applications. As such, IBM Workload Deployer will attempt to place the two custom nodes on different physical machines in order to prevent a single point of failure. Of course, this depends on having two hypervisors with enough resource (CPU, memory, storage) to host the virtual machines, but the appliance makes that decision in the first placement stage.
After considering compute resource and high availability, IBM Workload Deployer moves to the last stage of placement: license optimization. In this stage, the placement subsystem attempts to place the virtual machines on hypervisors in a way that minimizes the licensing cost to you. The appliance can do this because it is aware of IBM virtualization licensing rules and takes those into account during this stage (if you aren't familiar with virtualization licensing rules and you are curious, ask you're sales representative to explain some time). During this stage, it will not violate any resource overcommit directives or rules in place, nor will it compromise system availability, but it will seek to minimize costs within these parameters.
At this point, I should make something clear that may already have occurred to you. You can override most of these placement rules by creating a cloud group containing only one hypervisor. In this case, IBM Workload Deployer will put all virtual machines on the single hypervisor until it runs out of compute resource (memory is likely to be the constraining factor). I would not suggest that you do this unless you have a good reason or you are in a simple pilot phase, but I do like to point out the art of the possible!
While not incredibly deep from a technical perspective, I do hope that this provided a few helpful details on what goes on during the placement stages of deployment. If you have any questions, do let me know.
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.
When it comes to building and using WebSphere CloudBurst patterns, people always ask me if I have any best practices. It turns out, I do. In fact, I have a singular piece of advice that wraps it all up: Build WebSphere CloudBurst patterns in a way such that once deployed, there is no after-the-fact, manual configuration for the running environment. That means, build the pattern so that it not only contains all the nodes necessary for your application environment, but it also contains all the configuration necessary for the environment.
Put like this, most everyone I talk to agrees with me. However, they quickly recognize that, absent this really cool integration with Rational Automation Framework for WebSphere, this means they will be writing scripts for many configuration actions and including them in patterns in the form of script packages. For users not familiar with configuration scripting for our WebSphere products, this can be a daunting proposition. But... it shouldn't be!
Recently, I put together a short presentation that lays out an iterative approach for developing script packages for WebSphere CloudBurst. Specifically, the presentation focuses on developing configuration script packages for the WebSphere Application Server (though the general concepts apply to all Hypervisor Edition products equally). I believe this method is useful for anyone, from novice users to WebSphere scripting gurus. The basic process goes something like this:
Identify: Identify the target WebSphere Application Server topology and configuration for your application environment.
Deploy: Build a WebSphere CloudBurst pattern that matches your desired topology and deploy it to your cloud.
Develop and Test: Develop and test your configuration script. Not a WebSphere Application Server scripting ninja? No worries. Use the Command Assistance feature in the WebSphere Application Server v7 administration console. This feature shows you the wsadmin commands that match the actions you manually take in the console. This affords a lower barrier of entry for those not familiar with wsadmin.
Package: Package up the resulting scripts into a script package along with metadata that describes the package.
Modify and redeploy: Load the new script package into your appliance, add it to your pattern, and then redeploy. Upon deployment completion, verify the scripts produce the desired result.
The presentation provides detail on the above steps and walks through an example scenario for this process. I am embedding it below, and I hope it proves useful. As always, feel free to send in any questions or comments.
A while back I had a four part FAQ series inspired by questions arising from customer visits discussing the first release of WebSphere CloudBurst. With the recent release of WebSphere CloudBurst 2.0, I think it is a good time to revisit an FAQ series with an entirely new set of questions.
For the first part of the series, I want to address a question we get all the time now: "What is the difference between WebSphere CloudBurst and WebSphere Virtual Enterprise?" This question was always fairly common, but now even more so because the new Intelligent Management Pack option for WebSphere Application Server Hypervisor Edition allows you to deploy WebSphere Virtual Enterprise cells using WebSphere CloudBurst.
Fundamentally, the difference between the WebSphere CloudBurst Appliance and WebSphere Virtual Enterprise is a complementary one. WebSphere CloudBurst provides a means to create your application environments, deploy them into a shared, cloud environment, and then manage them over time. In this respect, the appliance focuses on bringing cloud-like capabilities to the application infrastructure layer of your application environments. WebSphere CloudBurst does give you management capabilities for your running, virtualized application environments (i.e. applying maintenances and fixes), but for the most part those capabilities do not extend into the application runtime environment.
Now, you may ask why WebSphere CloudBurst does not extend its reach into the application runtime. The answer is simple: We already have a solution that does just that, WebSphere Virtual Enterprise. WebSphere Virtual Enterprise provides capabilities that allow you to dynamically and autonomically manage your application runtime. You can use WebSphere Virtual Enterprise to not only assign performance goals to your applications, but also to declare the importance of a given application meeting its goals relative to other applications in your organization. This enables the dynamic management of your applications and their resources such that your applications perform according to their goals and relative importance to your business. Simply put, you get an elastic runtime at the application layer of your application environments.
As I said, WebSphere CloudBurst and WebSphere Virtual Enterprise are complementary solutions. Both enable notions of cloud computing, but at different layers of your application environments. WebSphere CloudBurst hones in on the application infrastructure components, while WebSphere Virtual Enterprise zeros in on the applications running in those environments. The new Intelligent Management Pack for WebSphere Application Server Hypervisor Edition means that WebSphere CloudBurst can now dispense WebSphere Virtual Enterprise environments into your on-premise cloud. That means you can take advantage of these complementary solutions from a single and simple management plane.
I hope this helps to clear things up. As always, questions and comments are welcome!
May is almost here and that means that IBM IMPACT is right around the corner. Just like years past, IMPACT 2010 will be a great chance to get valuable education and insight into IBM WebSphere software and software from across the IBM software family. If you want to hear how IBM software is leading the march toward a smarter planet, register now.
IMPACT 2010 will be a great chance to hear the WebSphere cloud computing story. There will be multiple sessions on the WebSphere CloudBurst Appliance. These include customer-led sessions, internal adoption stories, overviews, and much more. I'll be there running a hands-on lab and delivering a session that discusses integration between WebSphere CloudBurst and IBM Rational tools. Of course, there is more to WebSphere and cloud computing than WebSphere CloudBurst. We have several other sessions that will detail all of IBM WebSphere's work in the cloud.
If you are interested, I put together a short video discussing some of the sessions on tap for WebSphere and cloud computing at IMPACT 2010. I'd also encourage you to check out the social media site for IBM IMPACT 2010. On that site, you will find tweets, videos, and blogs about the conference. Don't forget to sign up, and I hope to see you in Las Vegas!
-- Dustin Amrhein
The reason I suggest the application proxy approach is twofold. First, it affords you the ability of having custom interactions with the REST API. For instance, you may insert logic into the server-side proxy code that returns only a subset of the JSON data contained in the response from the appliance. Alternatively, in an effort to reduce the chattiness on your client-side, you may join JSON data from multiple different REST requests to the appliance to fulfill a single client request. You may even decide to represent the data in an all together different format than JSON. All of these options and many more are available to you if you implement an application-based proxy to the REST API.
The second reason I suggest the application approach is that it is easier, and seemingly safer, to not deal with user passwords on the client-side. If you setup your application proxy, you can configure it to retrieve the appropriate password from a secure location (like an encoded file) based on information passed along in the request. This means the password information is only present in the request (in encoded form of course) from the application proxy to the WebSphere CloudBurst Appliance.
The good news about the application-based proxy approach is that it is simple to put in place. I composed one using the open source Apache Wink project. The Apache Wink project is an open source implementation of the JAX-RS specification (and then some), and it enables you to develop POJOs that are in turn exposed in a RESTful manner. In my case, I had a single resource POJO:
The Apache Wink runtime routes any HTTP GET request whose path is like /resources/* to the getResources method in the WCAResource class. This method passes along information taken from the query string (the host name of the target WebSphere CloudBurst Appliance and the requesting WebSphere CloudBurst username), as well as the HTTP path information and sends it on to the getResource method declared as follows:
The getResource method above uses the WebSphere CloudBurst host name and the request path to construct the URL for the corresponding WebSphere CloudBurst REST API call. Next, it constructs an Apache Wink Resource object and sends the REST request along to the WebSphere CloudBurst Appliance. How do we authenticate this request? We use the WebSphere CloudBurst username (sent as a query string parameter) to retrieve the appropriate encoded password information. Once we have that, we construct the necessary header for basic authorization over SSL.
The application-based proxy shown here is simply a pass-through. It does not manipulate the data returned from the WebSphere CloudBurst REST API, nor does it map a single client-side call to multiple REST requests. However, it would be simple enough to extend it to do any of those things. If you have any questions about the code here, please let me know. I'd be happy to share more of the code, or talk about how and where to extend it.