Knowledge: Managing KVM on IBM Z with oVirt

oVirt v4.2 introduced support for the KVM hypervisor on IBM Z (a.k.a. s390x). This article provides step-by-step instructions on how to include IBM Z hosts in an oVirt data center.

Prerequisites

To get started, it is necessary to have an instance of the oVirt engine running (self-hosted or installed on top of CentOS) on an x86 system. In case the engine manages a pre-existing data center, there will be at least one storage domain configured to hold image files. Otherwise it is necessary to define a new storage domain which typically involves setting up an NFS server. Finally, a partition on an IBM Z or LinuxONE system is needed.

Preparing the KVM Host

Currently, the oVirt project provides ready-to-use packages in a yum-Repository for IBM Z hosts running Fedora 27. In order to enable Fedora 27 for oVirt, the following steps have to be taken:

1. Install Fedora 27 on the IBM Z system
   
   
2. Install pre-requisite packages by executing the following commands
   

   dnf install yum
   dnf install python-firewall
   dnf install http://resources.ovirt.org/pub/yum-repo/ovirt-release42.rpm

3. If you want to use the latest snapshot version of oVirt:
   

   dnf install http://resources.ovirt.org/pub/yum-repo/ovirt-release42-snapshot.rpm

4. Create a file kvm.conf in the directory /etc/modules-load.d/ with the following content
   

   # Preload KVM module
   kvm

5. The host's OSA network interface must be configured to allow the interface to be operated in promiscuous mode.
   Use
   
      chzdev qeth 0.0.1234 bridge_reflect_promisc=primary
   
   to persistently enable the setting for the OSA interface with device number 1234. In case you do not know the device number of the OSA interface, use lsqeth to find out.

Adding a Cluster

Hosts (and virtual machines) are organized in clusters. A cluster will contain hosts with common characteristics, like CPU identical architecture and type, software levels, etc.
Therefore, the first step would be to add a new cluster for IBM Z hosts. To do this, log in to the administration portal and click on the “n Clusters” link on the dashboard page.

On the next page, clicking on the top right button labeled “New” will bring up a pop-up for the new cluster definition:

• Enter a name for the new cluster,
• select s390x as the CPU architecture, and
• leave everything else unchanged.

Note: If model specific features should be exploited in the virtual machines, it is necessary to select the respective CPU type.
E.g. select “IBM z13s, z13” in case you require features that have been introduced with the z13 machine.

Part 1

Part 2

Part 3