In WebSphere CloudBurst, a script package is your vehicle to provide custom middleware configuration. This may mean installing applications, configuring application dependencies, or otherwise tuning the middleware layer. Script packages are essentially ZIP files that include some executable (shell script, wsadmin script, Java program, etc.), and optionally, artifacts that support the execution of the script. As was the intention, you can achieve just about anything you want with a script package. This allows you to be as flexible and creative as you need to be, but it can also leave you asking "Where do I start?" In this post, I want to take an in-depth look at constructing and using a script package in WebSphere CloudBurst.
Specifically, I want to create a script package that supplies configuration functionality for something I believe a fair number of you do: change the default ports used in WebSphere Application Server. To create this and deploy a pattern using the script package, I do the following:
Create a shell script that configures the desired ports
Add the new script as a WebSphere CloudBurst script package
Create a pattern with the new script package
Deploy the pattern and verify the result
First things first. I create the following shell script that configures the ports:
The script uses documented ANT commands included with the WebSphere Application Server to update the ports based on a starting port number. You will notice the script first sources the /etc/virtualimage.properties file. This file is automatically created by WebSphere CloudBurst on every virtual machine it starts. The file is a key/value file with basic information about the WebSphere cell such as the install root ($WAS_INSTALL_ROOT), the profile name ($PROFILE_NAME), host name ($HOSTNAME), and more. For a full list of the data that WebSphere CloudBurst includes in this file, check out this documentation.
In addition to utilizing the standard set of variables provided by WebSphere CloudBurst, my script above also makes use of the $STARTING_PORT variable. Obviously this variable is not in the standard set. In fact, I define the STARTING_POINT variable when I define my new script package in WebSphere CloudBurst.
First I zip up the shell script above and attach it to the new script package. Next, I tell WebSphere CloudBurst where to unzip the script package on the virtual machine, how to invoke the included script, and the name of any parameters to associate with the script. Once that is done I can use the script package in a new pattern.
For the sake of simplicity here, I create a new pattern by cloning an existing WebSphere Application Server single server pattern. I drag and drop the new Configure ports script package on the single part and end up with the pattern shown below.
Now I am ready to deploy the pattern by clicking the Deploy button. During the deployment process I configure each part in the pattern (in this there is only a single part). I supply configuration information like virtual memory allocation, WebSphere cell name, WebSphere node name, and password information. In addition, I also supply a value for the STARTING_PORT parameter that is part of the Configure ports script package included in the pattern. The value I supply here will get inserted into the /etc/virtualimage.properties file on the virtual machine, and the value's key will be STARTING_PORT.
Once the configuration information is supplied, I click OK on the configuration panel and deployment panel, and WebSphere CloudBurst goes about standing up my virtualized WebSphere cell and running my script to configure the ports for the server instance. When it is done, I login to the WebSphere Application Server administration console to verify my results. To do this, I navigate to the configuration for the single application server instance, and pull up its port definitions.
Based on the results I can see my customizations took effect. I successfully captured my own unique WebSphere environment (in this case with a custom port range) in the form of a pattern. This custom environment can be deployed as many times as I need, in an automated fashion, and I'm guaranteed consistent results each and every time.
I hope this gives you a better idea of what script packages are all about and how they can utilize both WebSphere CloudBurst and user-supplied data that exists in the /etc/virtualimage.properties file of each virtual machine. If you have any questions let me know. I'm on Twitter @damrhein, or you can leave a comment right here.
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.
In my last post, I concentrated on the new enhancements to WebSphere CloudBurst 126.96.36.199. 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).
One of my favorite things to do with users or potential users of WebSphere CloudBurst is to help them understand how they can construct a custom environment using the appliance. Typically, we take one of their existing application environments and discuss the configuration steps that contribute to its makeup. From there, we map the required configuration actions to different customization capabilities in the appliance. It is one thing to talk about how you can customize every layer of your application stack with WebSphere CloudBurst, it is quite another to talk about it in the context of an existing environment. This exercise usually serves to greatly enhance a user's understanding of how to construct tailored environments with the appliance.
While I cannot take every one of you through this exercise in the context of one of your own application environments, I can propose a scenario that will help to illustrate the WebSphere CloudBurst customization process. Consider that I want to deploy a clustered WebSphere Application Server environment whose application server instances utilize WebSphere DataPower XC10 for HTTP session management. In order to deploy such an environment, I would need to do the following:
Install an OS and WAS
Install the WebSphere eXtreme Scale Client binaries - required for integration
Construct a clustered cell
Augment profiles with WebSphere eXtreme Scale profile templates
Configure the application server instances to use WebSphere DataPower XC10 for session management
So those are the steps, but how do they map to WebSphere CloudBurst? First, I know that the WebSphere Application Server Hypervisor Edition image used by WebSphere CloudBurst encapsulates the installation of the OS and WAS. I also know that WebSphere CloudBurst will automatically construct the clustered cell during the deployment process. That means I need to address the installation of client binaries, augmentation of profiles, and configuration of application server instances. In order to do this, I will use a combination of image extension and custom script packages.
To get started, I extend an existing WebSphere Application Server Hypervisor Edition image and simply install the WebSphere eXtreme Scale Client binaries. I then capture that image and store it as my own unique image in the WebSphere CloudBurst catalog. Now, you may wonder why I did not capture the profile augmentation in the custom image. Remember, you cannot change profile configuration during the extend and capture process as WebSphere CloudBurst resets the profiles as part of capturing the custom image.
My custom image encapsulates the installation of the client binaries, so now I turn to custom script packages. I need two in this case. One script package will augment a profile (either deployment manager or custom node) with the WebSphere eXtreme Scale profile template. The second script package will configure application server instances to use WebSphere DataPower XC10 for HTTP session management. Once done with these script packages, I have all the assets I need to build my target environment.
Using my custom image, I build a pattern that contains the number and kind of WebSphere Application Server nodes that I want. I use the advanced options to define a WebSphere Application Server cluster ensuring its creation happens during deployment. Next, I drag and drop the profile augmentation script onto the deployment manager and custom node parts in my pattern. Finally, I drag and drop the WebSphere DataPower XC10 configuration script onto the deployment manager. The pattern is now ready to deploy!
For those of you that are visual learners like me, this demonstration provides a nice overview of exactly what I wrote about above. Check it out and let me know what you think.