In true DevOps fashion, I nearly forgot to cover the mainframe after saying it warranted its own blog!
There is a lot going on right now in the mainframe space, so the question of mainframe language choices has several different answers. We’ve got Linux running on the mainframe, we’ve got cross-compiled open source capable of running on the mainframe natively, we’ve got mainframe-based containers and we even have traditional mainframe tools being ported to other platforms (hello, COBOL on Linux!) so that development can happen on smaller platforms but target the mainframe.
Taken in the order they came available, we have traditional mainframe development, in languages like COBOL and RPG, right on the mainframe in standard LPARs. This has gotten easier over the years, but is still basically the same development environment that was used in the 1980s, with prettier UIs.
Then we have Linux LPARs available that allow for development right on the mainframe. There are issues and differences from other Linux development environments, but not as many as you’d think. This approach gives a broad selection of development tools on a Linux platform, making it an appealing choice.
Next came containers, which can then run Linux in a container with the container offering the interfaces that Linux expects to find. This approach has the benefit of being more like development on other Linux platforms, but interaction with core services can still be platform-specific at times. This approach offers the breadth of open-source languages that came naturally with containers plus the few that have been ported over to z/OS.
Then came speed porting. The biggest weakness of the above options was that it took too long for vulnerabilities to be addressed and new functionality to be moved over to the mainframe. The fact is that porting a language took time, and wasn’t as rapid as the response for the core Linux kernel. There has been a movement to improve the dev tools that create the ports, and now response time to CVEs or improvements in the kernel is much better. A side effect of this movement has been increased availability of languages and tools that are used by DevOps to get things done.
Finally, we have recently received support for traditional languages on other Linux platforms. Most notably, given the number of lines of code out there, COBOL is now officially supported on Linux, meaning you can develop on the desktop without a ton of overhead, and then deploy to the mainframe. This has the effect of enabling DevOps processes and mentality for more traditional languages. This is still new, and the differences between developing on one platform and deploying on another will have to be worked out, but it is a step in the right direction.
So what should you use?
Mainframes are generally a more controlled environment than most DevOps teams are used to. The work required to support and update a given language, keeping it and its libraries up-to-date is more complex than just a generic Linux system, and that gives rise to very focused shops in the mainframe space. Generally speaking, you will be told what to use, or more to the point, which languages are supported. If you get input into the process, recommend Python, as it has the biggest pool of developers and libraries out there at the moment. But chances are, the mainframe team already has a language in place that they want DevOps teams to focus on, and in that case, use what’s available.
No matter which language you end up using, API-wrapping mainframe functionality is a time honored tradition at this point, make the mainframe do the heavy lifting and return just what your application needs. Think of it as a big, smart database that can pre-process results for you at high speed, in high volumes.
And keep rolling.
Mainframes have been around forever. They’ve been pronounced dead dozens of times, and yet the security, stability and locality of a mainframe keeps them in the mix. Data gravity helps too – the data is there, the routines to do processing on the data are there, handing that data off to another platform for presentation isn’t that big a deal, and the mainframe just keeps ticking along. Because (at this point) generations of developers have made it tick. Keep that tradition alive if you’re in a mainframe shop; they are literally the core of systems in the places they are in heavy use.