z/VM System Requirements


IBM z Systems hardware requirements are based on both the applications and the load on the system.

Active Engine Guide

Active engine is used as an initial configuration and management tool during deployed machine startup. Currently the z/VM driver uses zvmguestconfigure and cloud-init as a two stage active engine.

Installation and Configuration of zvmguestconfigure

Cloudlib4zvm supports initiating changes to a Linux on z Systems virtual machine while Linux is shut down or the virtual machine is logged off. The changes to Linux are implemented using an activation engine (AE) that is run when Linux is booted the next time. The first active engine, zvmguestconfigure, must be installed in the Linux on z Systems virtual server so it can process change request files transmitted by the cloudlib4zvm service to the reader of the virtual machine as a class X file.


An additional activation engine, cloud-init, should be installed to handle OpenStack related tailoring of the system. The cloud-init AE relies on tailoring performed by zvmguestconfigure.

Installation and Configuration of cloud-init

OpenStack uses cloud-init as its activation engine. Some Linux distributions include cloud-init either already installed or available to be installed. If your distribution does not include cloud-init, you can download the code from https://launchpad.net/cloud-init/+download. After installation, if you issue the following shell command and no errors occur, cloud-init is installed correctly:

cloud-init init --local

Installation and configuration of cloud-init differs among different Linux distributions, and cloud-init source code may change. This section provides general information, but you may have to tailor cloud-init to meet the needs of your Linux distribution. You can find a community-maintained list of dependencies at http://ibm.biz/cloudinitLoZ.

As of the Rocky release, the z/VM OpenStack support has been tested with cloud-init 0.7.4 and 0.7.5 for RHEL6.x and SLES11.x, 0.7.6 for RHEL7.x and SLES12.x, and 0.7.8 for Ubuntu 16.04.

During cloud-init installation, some dependency packages may be required. You can use zypper and python setuptools to easily resolve these dependencies. See https://pypi.python.org/pypi/setuptools for more information.

Image guide

This guideline will describe the requirements and steps to create and configure images for use with z/VM.

Image Requirements

  • The following Linux distributions are supported for deploy:

    • RHEL 6.2, 6.3, 6.4, 6.5, 6.6, and 6.7

    • RHEL 7.0, 7.1 and 7.2

    • SLES 11.2, 11.3, and 11.4

    • SLES 12 and SLES 12.1

    • Ubuntu 16.04

  • A supported root disk type for snapshot/spawn. The following are supported:

    • FBA

    • ECKD

  • An image deployed on a compute node must match the disk type supported by that compute node, as configured by the zvm_diskpool_type property in the zvmsdk.conf configuration file in zvm cloud connector A compute node supports deployment on either an ECKD or FBA image, but not both at the same time. If you wish to switch image types, you need to change the zvm_diskpool_type and zvm_diskpool properties in the zvmsdk.conf file, accordingly. Then restart the nova-compute service to make the changes take effect.

  • If you deploy an instance with an ephemeral disk, both the root disk and the ephemeral disk will be created with the disk type that was specified by zvm_diskpool_type property in the zvmsdk.conf file. That property can specify either ECKD or FBA.

  • The network interfaces must be IPv4 interfaces.

  • Image names should be restricted to the UTF-8 subset, which corresponds to the ASCII character set. In addition, special characters such as /, \, $, %, @ should not be used. For the FBA disk type “vm”, capture and deploy is supported only for an FBA disk with a single partition. Capture and deploy is not supported for the FBA disk type “vm” on a CMS formatted FBA disk.

  • The virtual server/Linux instance used as the source of the new image should meet the following criteria:

    1. The root filesystem must not be on a logical volume.

    2. The minidisk on which the root filesystem resides should be a minidisk of the same type as desired for a subsequent deploy (for example, an ECKD disk image should be captured for a subsequent deploy to an ECKD disk).

    3. The minidisks should not be a full-pack minidisk, since cylinder 0 on full-pack minidisks is reserved, and should be defined with virtual address 0100.

    4. The root disk should have a single partition.

    5. The image being captured should not have any network interface cards (NICs) defined below virtual address 1100.

In addition to the specified criteria, the following recommendations allow for efficient use of the image:

  • The minidisk on which the root filesystem resides should be defined as a multiple of full gigabytes in size (for example, 1GB or 2GB). OpenStack specifies disk sizes in full gigabyte values, whereas z/VM handles disk sizes in other ways (cylinders for ECKD disks, blocks for FBA disks, and so on). See the appropriate online information if you need to convert cylinders or blocks to gigabytes; for example: http://www.mvsforums.com/helpboards/viewtopic.php?t=8316.

  • During subsequent deploys of the image, the OpenStack code will ensure that a disk image is not copied to a disk smaller than the source disk, as this would result in loss of data. The disk specified in the flavor should therefore be equal to or slightly larger than the source virtual machine’s root disk.