The IBM Institute for Business Value, pursuing transformation like digital natives, Oct 2022 stated: Digitally native firms approach technology not as an enabler of business strategy, but as a central part of that strategy itself, integral to business direction and opportunity.
The adoption of container technology is increasingly becoming a top deployment choice across organizations. The State of the Mainframe, IDC Multiclient Study, December 23, 2022 found that of those surveyed, 90% indicated they would be running containerized applications in production by 2027.
IBM has been building its container portfolio as an integral part of its hybrid cloud strategy.
In July 2019, IBM partnered with Red Hat to enable OpenShift on Linux on Z. IBM Container Extensions (zCX) was introduced with z/OS 2.4 in Sept 2019 and zCX Foundation for Red Hat OpenShift was subsequently introduced in March 2022. With the IBM z/OS Container Platform offering (zOSCP) in March 2024, IBM is expanding the portfolio for container technology that runs on IBM Z to now include containers that run natively on z/OS.
Container images are both architecture specific and Operating System specific; meaning you need to build an image for the target operating system. IBM provides the ability to run containers on the s390x architecture on Linux. Linux applications are packaged up or ”containerized” for the s390x architecture and run on Linux on Z or run in a z/OS address space utilizing zCX. With the introduction of zOSCP, containerized z/OS UNIX applications are built for the s390x architecture and run on z/OS. This provides clients with a choice of running their Linux application on either Linux on Z or on z/OS (via zCX) and their z/OS UNIX applications on z/OS (via zOSCP) based on their use case and where their data resides.
Technology Overview
Let’s take a deeper look at the underlying technologies and platforms for each for each of these products.
IBM z/OS Container Platform, zOSCP, provides a container runtime, based on industry standard open-source container technologies, that enables z/OS UNIX applications to be containerized and run natively on z/OS.
With IBM Z Container Extensions (zCX), clients can run Linux on Z applications on z/OS utilizing either Docker or Red Hat OpenShift technologies.
With Red Hat OpenShift Container Platform (RHOCP) on IBM Z, clients can run Linux on Z applications on zVM or KVM Virtual Machines using Red Hat OpenShift technologies.
The zCX, zCX Foundation for Red Hat Open Shift and Red Hat Open Shift Container Platform on IBM Z offerings all enable Linux applications to run as containers whereas z/OS Container Platform enables z/OS UNIX applications to run as containers.
Where should I run my application: zCX, zOSCP or both
Client have a choice as to where to run their applications and determining the best fit requires considering the application, affinity to a particular environment and their business goals. They may choose IBM z/OS Container Platform, or IBM Z Container Extension, or IBM zCX Foundation for Red Hat OpenShift, or all of them.
Since IBM Z Container Extensions , zCX Foundation for Red Hat OpenShift and z/OS Container Platform all run on z/OS, they are each targeted to workloads with a high affinity to z/OS and share the same benefits of leveraging IBM Z Qualities of Service.
Shared benefits:
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Leverage IBM Z Qualities of Service: performance, privacy, availability, reliability, security
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Enable performance improvements through data affinity
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Run in a z/OS address space alongside traditional z/OS workloads
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Enable cloud native development
Besides the fundamental difference in container technology where zOSCP runs containerized z/OS UNIX applications and zCX runs containerized Linux applications, there are two additional factors, the level of management that is desired and zIIP eligibility, that clients might want to consider when determining where to run their containerized applications. zOSCP supports traditional z/OS operational management (security, resource management and networking) at the container level whereas zCX integrates z/OS operational management at the address space level. Regarding zIIP eligibility, all zCX offerings run on zIIPs, whereas for zOSCP, only zIIP eligible z/OS workloads are able to run on zIIPs.
Clients who are already running Red Hat OpenShift in their enterprise may choose zCX Foundation for OpenShift, whereas clients new to container technology might want to choose zOSCP to get started. Some applications may have an affinity to Linux for which zCX Foundation for OpenShift would be a natural choice while for other applications, running natively on zOSCP might be the right environment.
It could come down to where the application was developed (e.g. choosing zCX for an application that is only containerized for Linux) or simply where you have the most available capacity.
Cris Desnoyers, Mike Fitzpartick, Kershaw Mehta, Matthew Webster, August 2024