This chapter describes the original obstacle that was faced by the Walmart development team and how the engineering team met this challenge by providing a service that follows the cloud computing model. The authors describe the characteristics of this model and how both IBM z/OS and IBM CICS offer the capabilities to make these characteristics available.

In this chapter and throughout this book, the authors also consider the challenges that the cloud presents to traditional IT roles and how to address them.

This chapter includes the following topics:

A team of developers working on an application for a non z Systems platform needed a distributed caching service. Their existing solution had performance and availability issues, did not scale, and was unreliable. They were facing a rapidly approaching deadline for their application to go into production. A solution to this problem was proposed by the CICS platform engineers, but this solution was met with skepticism because of perceived complexity and lack of agility of the mainframe platform

Walmart embarked on the journey to find a solution to this challenge with an eye toward cost neutrality, where there was no initial investment and the hope was that someday the project would be self-funding

Have you noticed the attention that is being given to cloud service providers? The reason for this attention is that service providers are following a model where the developer is the customer and providers are catering to their needs. Expressed differently:

The reason that external cloud service providers are being heard is that they changed their behavior and focus to those of the consumer. In the case of Walmart, the consumer is the application developer. The user of a service ultimately decides the fate of the service. Even if a service is low-cost and reliable, developers will pursue services elsewhere if the service is not easy to consume and free.

Just as developers seek service providers that satisfy their needs, business units do the same. Ultimately, businesses do not need IT: They need capabilities. These capabilities include functions, such as servicing a customer, collecting money, and moving inventory. IT happens to be an effective way of providing these capabilities, but it is still only a means to an end. Business demands are dynamic and can change rapidly. IT must accommodate these changes as needed. Providing developers accessible, easy to use services allows them to be responsive to business needs.

Microservices architecture is becoming the standard approach for developing, deploying, and managing applications and application components. Small teams work independently and use their technology of choice to create services that are accessed by easily consumed application programming interfaces (APIs). CICS provides the multi-language run time for such teams on a robust, secure, highly scalable z Systems platform. The resulting microservices are stand-alone pieces of code, each with a finite function that can be accessed by anyone on the team and independently deployed. The APIs can call other services or be used alone. It is all about the service that is faster, cheaper, and more flexible than traditional IT provided.

Timely delivery of a business capability is the ultimate objective of any development activity. Developers understand the need for the risk protection that traditional IT groups provide. It is inefficient to wait to move applications to production, wait for a service to be provisioned, or to have so much governance that they cannot be agile. Walmart found that by focusing on and addressing the needs of the developer as the consumer, they increased the speed at which functionality is delivered to the business.

The National Institute of Standards and Technology (NIST¹) defines the five essential characteristics of cloud computing as shown in Figure 1-1. These characteristics can be satisfied by CICS Transaction Server (TS) on z/OS. You could argue that IBM Multiple Virtual Storage (IBM MVS™) was the original cloud system, as the functions in the operating system, together with the middleware and database, provided most of the characteristics of today’s cloud systems. With CICS TS on z/OS, adopting cloud can deliver maximum business value from small changes to applications and processes.

Web services (or in general terms, application services) provide broad network access to functions that are hosted in CICS. Support for SOAP web services has been available since CICS TS V3.1, with JSON web services support arriving in CICS TS V4.2. Use of IBM WebSphere Application Server Liberty profile for z/OS in CICS TS V5.1 further strengthened service enablement, providing servlet, RESTful, and SOAP web service options for Java applications.

The approach that was taken by Walmart is based on ReSTful services and is described in Chapter 3, “The service provider” on page 13. Chapter 4, “The CICS systems programmer” on page 27 describes how CICS services are used.

The economics of cloud depends on resource pooling with multiple tenants sharing underlying infrastructure. The best practice for most CICS customers is to deploy a cluster of servers or cloned regions, and this approach is used by Walmart. The configuration that was chosen is described in Chapter 4, “The CICS systems programmer” on page 27.

Rapid elasticity on the z/OS platform is achieved by starting more servers and ensuring that those servers that are already running have the resources (for example, the CPU and storage) that they need when workloads increase. In addition to z/OS workload management (WLM), clients can take advantage of the 64-bit exploitation of CICS and the ability to run thread-safe applications. For more information about the approach that was taken by Walmart, see Chapter 5, “The z/OS systems programmer” on page 45.

A critical difference between service-oriented architecture (SOA) and cloud is the need to provide a measured service. The CICS monitoring facility (CMF) allows you to measure the resource consumption of every service request. For more information about how Walmart uses strict naming conventions with CMF to uniquely identify each service consumer, see Chapter 4, “The CICS systems programmer” on page 27.

As you know, the direction of a business is ultimately determined by its customers. The ability to quickly adapt business services to the needs of the customers requires on-demand self-service access to IT assets for Walmart developers. For more information about the user experience with a provisioning portal, see Chapter 2, “The service consumer” on page 7. For more information about how the developer experience fits into the broader perspective of DevOps, see Chapter 7, “DevOps perspective” on page 67. Walmart takes advantage of the web server that is includes with CICS to host this portal and uses resource definition online (RDO) and other facilities to dynamically create the resources required by each service instance.

Walmart did not set out to explicitly use z/OS and CICS to deliver cloud services. The initial goal was to address the obstacle that the application development team was experiencing (see 1.1, “The development obstacle” on page 2).

While working on a solution, it became apparent that not only did CICS on z/OS have the capabilities that are needed to solve the issue, it also provided the means to deliver the capability as a service. If done correctly, this service could then be called by anyone who needs the same functionality and it could be called from any platform.

The easy way to address the development obstacle is to create a single enterprise service. However, it was at this point that the actions became intentional. By following the NIST standards for cloud services (which included the creation of a self-service provisioning mechanism and metering), a cloud service was born. After the model was developed, Walmart was able to reuse it. Many other z/OS cloud services were created later.

Part of the benefit of a cloud service is that it frees the consumer from having to know or be concerned about the operating environment hosting the service. The consumer can call the service as an HTTP endpoint, without concern for the underlying infrastructure. In fact, the original z/OS cloud service that was developed was created for consumption by a non z Systems team. The application development team needed a resolution to the development obstacle that was fast, inexpensive, and flexible. They got these features and more.

The first z/OS cloud service that Walmart created contained base functions and opened the door to a new way of satisfying the application developers. The new thinking became the idea of getting a service available quickly to support agility, and then to go back and make enhancements. These principles are the principles of the agile development methodology.

This thinking allows the ability to master a step, provide updates, and then master the next step. One of the key issues is to provide governance, which at first might be manual, but that can continue to evolve and become automated. Early feedback from the service consumer provided input for prioritization of new function and assurance that the service met the business need at hand.

It is important to understand that none of the consumers of the services that Walmart created sought out a CICS on z/OS solution. And inversely, the z/OS and CICS teams did not seek to be an enterprise cloud service provider. The goal was to meet the needs of the application developer. The outcome is that z/OS and CICS are now a private cloud service provider as part of a Walmart hybrid cloud strategy.

Walmart started its first service in their production sysplex environment and provided only a small amount of isolation by creating CICS servers (regions) that were specifically for the z/OS cloud service.

After it became apparent that the use of CICS cloud services would grow, creating a greenfield implementation that was reusable allowed the freedom to move away from dependencies on traditional systems. These traditional environments are commonly not ideal to host services because of high levels of dependencies among processes, the dynamics of workloads, and restrictive change management processes.

The difference is how the services are provided. Traditional environments typically follow a long change cycle, might deploy with a strategy that every system must be the same, and lose the ability to be agile. The cloud services sysplex is run with a thought of fit for purpose. For example, if one system can benefit from a newer code version, it is pushed to only that system to deliver the needed function. Languages and deployment environments are chosen based on which one meets the needs of the application.

Walmart embarked on this journey with an eye toward cost neutrality. One of the first services that was built performed much better than did the older application. It also returned savings in the form of resources saved; that is, a lower amount of capacity and memory were used. These savings were then used to create the next service. In this way, the cloud services environment was self-funding. The success demonstrated with this model led to the investment in the greenfield sysplexes.

With disruptive technologies continuing to emerge, traditional IT roles are no longer sufficient. Today’s system programmer spends more time in the system administrator functions and less time with their application programming counterparts.

The CICS system programmer can tend to have a silo view and forget the effect on the operational environment. The operations team might forget that they are not just keeping things running, but they are servicing their client. In this way, all of the IT functions depend on the needs and successes of each other.

Walmart learned that by increasing the communication and knowledge across traditional roles, a more efficient and more functional system is created. The more feedback in the cycle, the faster the changes are delivered, with the continued focus on the needs of the service consumer.

Chapter 2, “The service consumer” on page 7, Chapter 3, “The service provider” on page 13, Chapter 4, “The CICS systems programmer” on page 27, and Chapter 5, “The z/OS systems programmer” on page 45 focus on the concerns and actions that a specific IT role should consider. An increased focus on collaboration between the roles enhances the ability of the service provider to meet the needs of the service consumer.

This chapter described what motivated Walmart to become a cloud services provider; removing obstacles to developer productivity, while keeping a keen eye on cost.

By following the five essential characteristics of cloud, Walmart maximized business value by exploiting a number of key capabilities of CICS TS on z/OS. The remaining chapters of this book help you achieve the same success.