Open Source for IBM Z and LinuxONE

What does an open source project get from this? Supporting s390x can be a pain. Their CI instances are over provisioned and time-out, sometimes odd failures due to the odd architecture, maybe performance issues. That's more headaches and toil from volunteers. So besides the bragging rights (I guess?) and discovering latent bugs exposed by the exotic architecture, what's in it for a project to deal with this extra architecture

> what's in it for a project to deal with this extra architecture

You’d be surprised the number of companies who really want to run something on an obscure platform, and will pay $$$ to port stuff to it. Often the thing being ported isn’t even open source, it is some proprietary product, but that proprietary product has open source dependencies, and so someone ends up paid to port them to the obscure platform, to even try to upstream the port if the maintainers will take it.

Years ago, I knew of a small company which sold a CMS (I was going to work for them, but the job fell through when they couldn’t pay me enough); the CMS was proprietary, but it ran on an open source stack (LAMP). Some random customer said they’d only buy it if it was ported to IBM i (PASE, the AIX emulation environment), and they were willing to pay for the port, so it happened.

Later on, I worked for Oracle, and ended up on a project to port some ERP-related product to AIX - all because we had a big customer willing to pay millions for this product, but only if we made it run on AIX. And in the process I found an AIX-specific bug in JNA (the open source Java FFI library), and ended up helping the JNA developers to fix it

> Their CI instances are over provisioned and time-out

I can't speak to their managed Jenkins offering, but FWIW, we've had no major trouble running Zig's CI on 3 s390x-linux VMs, each with 8x z15 vCPUs and 32 GB of RAM.

They are definitely over-provisioned, though, so we have the job timeouts set ~3 hours higher than they ideally should be to deal with load spikes. But after we dialed those timeout values in, it's been smooth sailing from there. I'd even say it's one of our most stable CI platforms now.

I did reach out to Bruce Gilkes about the over-provisioning and he informed me that they are planning an upgrade to z17 later this year, so hopefully that'll improve the situation.

> What does an open source project get from this? ... So besides the bragging rights (I guess?) and discovering latent bugs exposed by the exotic architecture, what's in it for a project to deal with this extra architecture

The way I look at it, if Zig is going to be a serious C competitor, it must run in all the places that people run C in. Plus I just find it fun to do porting work since it involves a whole bunch of learning.

> So besides the bragging rights (I guess?) and discovering latent bugs exposed by the exotic architecture, what's in it for a project to deal with this extra architecture

I submitted the story, and I'm mentioned in it.

For me, it's about demonstrating my stuff runs everywhere Go does.

In particular, this makes s390x the only bigendian architecture I can test on "actual hardware" (vs. QEMU binfmt emulation).

What does an open source dev get out of their work at all? Satisfaction?

For the "traditional" open source model of give away the software and sell the support, s390x customers could be fantastic customers: love paying for support, lots of $$$, super sticky once you get them.

But yeah for a random indie dev the PITA makes it harder.

this literally is about ibm providing free cloud infrastructure and offering support for the community. what failures are you talking about? s390x is not an "exotic" architecture by any stretch and is pretty top-notch in terms of availability, reliance and performance, which is why it is still in use. the incentives both for the community supporting it and the manufacturer supporting the community seem pretty evident to me.

> what's in it for a project to deal with this extra architecture

> So besides the bragging rights (I guess?) and discovering latent bugs exposed by the exotic architecture, what's in it for a project to deal with this extra architecture

I submitted the story, and I'm mentioned in it.

For me, it's about demonstrating my stuff runs everywhere Go does.

In particular, this makes s390x the only bigendian architecture I can test on "actual hardware" (vs. QEMU binfmt emulation).

> Their CI instances are over provisioned and time-out

I can't speak to their managed Jenkins offering, but FWIW, we've had no major trouble running Zig's CI on 3 s390x-linux VMs, each with 8x z15 vCPUs and 32 GB of RAM.

I did reach out to Bruce Gilkes about the over-provisioning and he informed me that they are planning an upgrade to z17 later this year, so hopefully that'll improve the situation.

What does an open source dev get out of their work at all? Satisfaction?

But yeah for a random indie dev the PITA makes it harder.

Linux on IBM Z and IBM LinuxONE use the s390x hardware architecture to run various Linux distributions, including SUSE Linux Enterprise Server (SLES), Red Hat Enterprise Linux (RHEL), and Ubuntu. Tens of thousands of software packages are tested and distributed through these projects, and various community distributions.

But for some applications, a team at IBM pays special attention to make sure they compile and run as expected, or better. This work is often done as a collaboration between the open source projects themselves and the team at IBM. This effort is an on-going collaboration with every release of the software needing to be validated.

For the month of May 2026, the team worked to validate recent versions of the following:

Apache Cassandra
Apache Hbase
Apache HTTP Server
Apache Ignite
Beats
cAdvisor
Calico
Doxygen
Falco
Grafana
HAProxy
Htop
MongoDB Driver - Java
MongoDB Driver - PHP
MongoDB Driver - Ruby
Netty-tcnative
Neo4j
OPA
OpenResty
PHP
PM2
PostgreSQL
Python
R
RabbitMQ
Ruby
Terraform

The full list of validated software to date is available here: https://www.ibm.com/community/z/open-source-software/

Looking for open source software that's not maintained by this team? Visit the Open Mainframe Project Software Discovery Tool to search for what you're looking for across a number Linux distributions. And there are always folks from IBM and beyond working to enable more projects that we don't even know about!

It was a great month for s390x support in the broader open source community, with over 10 projects adding support! These included Kuadrant dns-operator CI and v0.17.0 release binaries, CI for go-simdjson and an update to their README, and CI for aba and a README update there too. The 0.6.0 release of poof includes s390x support, and go-bin had their first s390x wheels release with version 1.26.3. There is now s390x CI for nginx-opentracing, along with DockerHub images starting with version 0.42.0. The OpenSCM client has added s390x to its Supported Platforms as of the release of version 0.2.8. And finally, Terraform 1.15.4 has been released with s390x DockerHub images and binary downloads from their Install page. Over in our hosted GitHub Actions service for IBM Z and Power, we on-boarded ncruces/wasm2go and ncruces/go-sqlite3, and NumPy (which previously was only being tested on this infrastructure for IBM Power).

This month the Open Mainframe Project Mainframe Software Hub for Linux added builds for InfluxDB 3 Core and MySQL 8.4.8 and 9.6.0, and released updates for Spire and Beats. Do you happen to have some scripts and patches tucked away that you use for your own software builds for Linux on IBM Z and LinuxONE? We invite you to join us!

Are you a developer for an open source project interested in seeing your application made available to users on Linux on IBM Z and IBM LinuxONE? Your first stop should be the IBM LinuxONE Community Cloud where you can sign up for a free virtual machine for 120 days where you can see how your application runs, and discover for yourself what you may need to change to get it to run well on Linux on IBM Z and IBM LinuxONE.

If you wish to have permanent virtual machines for development, testing, or to add to your CI system, you can fill out this form to apply for resources for your project.

See you next month!

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