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Reports of the mainframe's demise remain greatly exaggerated, even as DevOps takes hold in enterprise IT shops.
Mainframe DevOps causes consternation among enterprise IT pros charged to modernize legacy workloads. Mainframes are often the oldest and longest-running systems in enterprise data centers, and they play a crucial role for financial institutions in particular, where the mainframe's transaction processing speed and reliability remain unmatched by distributed systems.
The transfer of apps off the mainframe requires costly refactoring and data migration, and there's a shortage of skilled programmers available to do that work. But mainframes were never built for frequent, rapid changes to workloads that run on them, and they can drag down an entire DevOps pipeline that's needed to improve business agility.
Many firms ultimately plan to move away from the mainframe. But, for others, this is simply impossible and, in many ways, undesirable.
"We have more than 100,000 [mainframe] programs, some going back 20 years," said Pascal Rotilio, a senior consultant in charge of a z/OS-as-a-service project at BNP Paribas (BNPP), an international bank in Paris founded in 1848. "Some apps will leave the mainframe over time, but with more than a million transactions a day in productions, mainframes are still needed."
Mainframe DevOps tools evolve
Bringing BNPP's IBM z14 mainframes up to DevOps speed requires an overhaul to the company's app delivery pipeline and infrastructure platform, which is slated to begin in March 2019. BNPP will use recently updated and forthcoming features in IBM's z Systems Development and Test Environment (zD&T) Enterprise Edition to link familiar DevOps pipeline tools to the mainframe environment as part of this effort. IBM competitors such as Compuware, Micro Focus and CA also offer mainframe DevOps tools.
For BNPP, it's easier to alter the mainframe DevOps environment to support distributed systems' DevOps tools, such as Git code repositories, Artifactory artifact repositories and the Jenkins continuous integration tool, that a new generation of IT pros knows than to sit them down in front of green screens to learn mainframe commands, Rotilio said.
In December 2018, IBM took steps to bridge this gap with a set of features called Z Open Development, which is built on a 2017 port of Git for z/OS by Rocket Software. IBM will automatically add Z Open Development features to zD&T as part of regular software maintenance updates, including a technology preview of support for automated application unit tests in z/OS batch and customer information control system (CICS) environments.
BNPP is interested in Z Open Unit Test for batch programs on its z14 mainframes, but will wait for the tool to mature beyond the preview stage and add support for the IBM Information Management System (IMS), which the company uses heavily for transaction processing, Rotilio said. BNPP does not use CICS.
Once automated unit testing is in place for IMS workloads, BNPP will offer application development subcontractors visibility into the performance of application unit tests in development environments. Often, problems with application updates don't emerge until production and are triaged by the company's IT ops team, rather than fixed early in the development process.
"We expect to have continuous integration [for mainframe] when unit testing is available for IMS," Rotilio said. "It will also allow us to measure test code coverage."
IMS support for Z Open Unit Test is a high priority on the roadmap for IBM in 2019, the company said.
Mainframe DevOps pushes forward as budgets increase
Chris Gardneranalyst, Forrester
Despite mainframes' passé reputation, analysts said enterprises plan to increase, rather than decrease, their spending on mainframe infrastructure.
Among 273 North American IT decision-makers surveyed by Forrester in December 2018, 56% use mainframes, and 46% plan to increase their use of mainframes over the next two years. Another 36% predict it will stay the same.
In the long run, most enterprises -- aside from a few "mainframe unicorns" -- will refactor apps and move away from the mainframe.
"Financial services will have a need for mainframes for high transaction volumes and to address security concerns with mainframe features, such as built-in hardware encryption," said Chris Gardner, an analyst at Forrester Research who co-authored that mainframe modernization survey and report. "IBM wants everyone to be a mainframe unicorn, but not everyone's going to be."
Still, as near-term spending estimates indicate, that migration off the mainframe won't happen overnight, and most companies will require stopgap accommodations for mainframe DevOps.
"IBM Z Open Development is one more tool in the toolbox and can be used to replace a stage of development where a lot of organizations are still using very old-fashioned, manual processes," Gardner said.
Enterprises also should determine their long-term mainframe strategy before they invest in mainframe DevOps tools.
"Organizations must consider if they want to build out an entire mainframe DevOps tool set, or only apply the tools that make sense," he said.