Ubuntu for IBM Z and LinuxONE

Ubuntu s390x port is available from Xenial Xerus (16.04 LTS) release and up. The target architecture is zEC12 and up.



Please complete the form at http://www.ubuntu.com/download/server/linuxone to get access to ISO downloads.

The ISO contains multiple files in /boot/ sub-directory to load/IPL on LPAR, z/VM, and KVM.



  • Use ubuntu-bug tool

  • Include/add s390x tag to manual bug reports



  • Most packages are available
  • Juju local and manual providers are available
  • LXD and LXC are available
  • Cloud images are available
  • Docker is available
  • OpenStack Mitaka is available


Q: What Virtualization Modes are Supported?

A: Ubuntu is supported as:

  • A native install in an LPAR
  • A KVM instance within Ubuntu on an LPAR
  • A KVM instance within KVM for z Systems
  • A z/VM instance

Q: Is there an emulator I can use to run Ubuntu s390x on non-mainframe hardware?

A: Unfortunately there is currently no emulator support for Ubuntu s390x port - this includes current releases of Hercules, PDT, and QEMU.

Q: How to tweak boot arguments?

A: Simply edit /etc/zipl.conf and run sudo zipl to update the configuration.

Q: How to bump crashkernel limits?

A: Depending on the number of available devices crashdump setting in /etc/zipl.conf may not be appropriate. One can either increase it further, or limit the amount of devices visible to the kernel, and thus lower the requirements for the crashdump setting.

To ignore devices you can run cio_ignore tool to generate appropriate stanza to ignore all devices, but the currently active/in-use. Simply add the generated stanza to the boot parameters in /etc/zipl.conf:

$ sudo cio_ignore -u -k

A: Appropriately sized machines need to be used for the installation target. If one tries to install all available packages, all translations, all debug symbols, and all development packages - an appropriate amount of disk space and installation memory required - otherwise it can be possible that the system runs out of disk space and/or out of memory. In the latter case the oom-killer may kill random processes, incl. the installer itself.

A good common sense is to just select in d-i the minimal required components and packages for an initial setup and to install anything else after the initial setup is completed on top of that. This also provides a better user experience due to the more convenient package management tools available on an installed system. It is not really possible to estimate the required RAM if installing all of the archive options, because the services are started upon installation. And they may even have different requirements that change from version to version. The disk space estimation can also be done quite roughly and is based on the package unpacked size. But keep in mind that postinst package scripts may create more files that, again consume even more disk space. For example postgresql create and starting new clusters, or backups and snapshots are taken which at the end can eat a lot of space in /var.

Q: How reasonably small can an Ubuntu system be?

A: As usual it depends on what the system is used for and which packages are needed. For a small base installations 2GB of RAM is sufficient - even 1GB systems are possible, but I see them mainly as z/VM guests and KVM virtual machines, rather than LPARs of that size. For testing and for just trying out certain aspects and functions such small with RAM down to 1GB systems are possible. But limit the installed components and packages in such an edge case to the bare minimum to not reach the system limits right away.

Q: How can LPAR installation be done in VLAN environments?

A: There are two way of installing Ubuntu on z Systems or LinuxONE on LPAR in a VLAN (IEEE 802.10) network environment: - automated d-i installation using preseed - interactive d-i installation with d-i priority Medium More details can be found here: https://ubuntu-on-big-iron.blogspot.de/2017/01/lpar-install-ubuntu-on-z-with-vlan.html

Q: Installing zipl boot loader fails if "/boot' is located on a multi-target device-mapper device

A: Partitioning step allows to configure LVM across multiple devices without requiring to setup a separate /boot partition. This may lead to failure to install the bootloader at the end of the installation, and failures to boot the resultant installations. (1680101) - This is fixed with 18.04.

Q: LVM configuration cannot be removed when volume groups with the same name are found during installation

A: Partitioner does not support installation when multiple conflicting/identical volume groups have been detected. For example reinstalling Ubuntu with LVM across multiple disk drives that had individual LVM installations of Ubuntu. As a workaround, please format disk drives prior to installation, or from the built in shell provided in the installer. (1679184)

Q: System cannot boot when root filesystem is on an LVM on two disks

A: A System cannot be booted up when it's root filesystem is on an LVM on two disks (either ECKD or FCP). After all needed disk devices are enabled by 'chzdev -e', one must run 'update-initramfs -u' so that the udev rules generated by chzdev are copied into the initramfs and become available at boot time. . (1641078)

S390X (last edited 2018-04-10 15:58:41 by frank-heimes)