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documentation.suse.com / SUSE Linux Enterprise Server-Dokumentation / Virtualization Guide / Introduction / Installation of virtualization components
Applies to SUSE Linux Enterprise Server 15 SP6

6 Installation of virtualization components

 

6.1 Introduction

 

To run a virtualization server (VM Host Server) that can host one or more guest systems (VM Guests), you need to install required virtualization components on the server. These components vary depending on which virtualization technology you want to use.

6.2 Installing virtualization components

 

You can install the virtualization tools required to run a VM Host Server in one of the following ways:

  • By selecting a specific system role during SUSE Linux Enterprise Server installation on the VM Host Server

  • By running the YaST Virtualization module on an already installed and running SUSE Linux Enterprise Server.

  • By installing specific installation patterns on an already installed and running SUSE Linux Enterprise Server.

6.2.1 Specifying a system role

 

You can install all the tools required for virtualization during the installation of SUSE Linux Enterprise Server on the VM Host Server. During the installation, you are presented with the System Role screen.

System Role screen
Figure 6.1: System Role screen
 

Here you can select either the KVM Virtualization Host or the Xen Virtualization Host roles. The appropriate software selection and setup is automatically performed during SUSE Linux Enterprise Server installation.

Tip
Tip

Both virtualization system roles create a dedicated /var/lib/libvirt partition, and enable the firewalld and Kdump services.

6.2.2 Running the YaST Virtualization module

 

Depending on the scope of SUSE Linux Enterprise Server installation on the VM Host Server, none of the virtualization tools may be installed on your system. They are automatically installed when configuring the hypervisor with the YaST Virtualization module.

Tip
Tip

The YaST Virtualization module is included in the yast2-vm package. Verify it is installed on the VM Host Server before installing virtualization components.

Procedure 6.1: Installing the KVM environment
 

To install the KVM virtualization environment and related tools, proceed as follows:

  1. Start YaST and select Virtualization › Install Hypervisor and Tools.

  2. Select KVM server for a minimal installation of QEMU and KVM environment. Select KVM tools to use the libvirt-based management stack as well. Confirm with Accept.

  3. YaST offers to automatically configure a network bridge on the VM Host Server. It ensures proper networking capabilities of the VM Guest. Agree to do so by selecting Yes, otherwise choose No.

  4. After the setup has been finished, you can start creating and configuring VM Guests. Rebooting the VM Host Server is not required.

Procedure 6.2: Installing the Xen environment
 

To install the Xen virtualization environment, proceed as follows:

  1. Start YaST and selectVirtualization › Install Hypervisor and Tools.

  2. Select Xen server for a minimal installation of Xen environment. Select Xen tools to use the libvirt-based management stack as well. Confirm with Accept.

  3. YaST offers to automatically configure a network bridge on the VM Host Server. It ensures proper networking capabilities of the VM Guest. Agree to do so by selecting Yes, otherwise choose No.

  4. After the setup has been finished, you need to reboot the machine with the Xen kernel.

    Tip
    Tip: Default boot kernel

    If everything works as expected, change the default boot kernel with YaST and make the Xen-enabled kernel the default. For more information about changing the default kernel, see Abschnitt 18.3, „Konfigurieren des Bootloaders mit YaST“.

6.2.3 Installing specific installation patterns

 

Related software packages from SUSE Linux Enterprise Server software repositories are organized into installation patterns. You can use these patterns to install specific virtualization components on an already running SUSE Linux Enterprise Server. Use zypper to install them: 

zypper install -t pattern PATTERN_NAME

To install the KVM environment, consider the following patterns:

kvm_server

Installs basic VM Host Server with the KVM and QEMU environments.

kvm_tools

Installs libvirt tools for managing and monitoring VM Guests in KVM environment.

To install the Xen environment, consider the following patterns:

xen_server

Installs a basic Xen VM Host Server.

xen_tools

Installs libvirt tools for managing and monitoring VM Guests in Xen environment.

6.3 Enable nested virtualization in KVM

 
Important
Important: Technology preview

KVM's nested virtualization is still a technology preview. It is provided for testing purposes and is not supported.

Nested guests are KVM guests run in a KVM guest. When describing nested guests, we use the following virtualization layers:

L0

A bare metal host running KVM.

L1

A virtual machine running on L0. Because it can run another KVM, it is called a guest hypervisor.

L2

A virtual machine running on L1. It is called a nested guest.

Nested virtualization has many advantages. You can benefit from it in the following scenarios:

  • Manage your own virtual machines directly with your hypervisor of choice in cloud environments.

  • Enable the live migration of hypervisors and their guest virtual machines as a single entity.

    Note
    Note

    Live migration of a nested VM Guest is not supported.

  • Use it for software development and testing.

To enable nesting temporarily, remove the module and reload it with the nested KVM module parameter:

  • For Intel CPUs, run: 

    > sudo modprobe -r kvm_intel && modprobe kvm_intel nested=1

  • For AMD CPUs, run: 

    > sudo modprobe -r kvm_amd && modprobe kvm_amd nested=1

To enable nesting permanently, enable the nested KVM module parameter in the /etc/modprobe.d/kvm_*.conf file, depending on your CPU:

  • For Intel CPUs, edit /etc/modprobe.d/kvm_intel.conf and add the following line: 

    options kvm_intel nested=1

  • For AMD CPUs, edit /etc/modprobe.d/kvm_amd.conf and add the following line: 

    options kvm_amd nested=1

When your L0 host is capable of nesting, you can start an L1 guest in one of the following ways:

  • Use the -cpu host QEMU command line option.

  • Add the vmx (for Intel CPUs) or the svm (for AMD CPUs) CPU feature to the -cpu QEMU command line option, which enables virtualization for the virtual CPU.

6.3.1 VMware ESX as a guest hypervisor

 

If you use VMware ESX as a guest hypervisor on top of a KVM bare metal hypervisor, you may experience unstable network communication. This problem occurs especially between nested KVM guests and the KVM bare metal hypervisor or external network. The following default CPU configuration of the nested KVM guest is causing the problem: 

<cpu mode='host-model' check='partial'/>

To fix it, modify the CPU configuration as follow: 

[...]
<cpu mode='host-passthrough' check='none'>
 <cache mode='passthrough'/>
</cpu>
[...]