How To Install KVM on openSUSE

Kernel-based Virtual Machine (KVM) is a powerful virtualization solution that transforms Linux into a hypervisor, allowing you to run multiple virtual machines on a single physical host. This guide will walk you through the process of installing and configuring KVM on openSUSE, providing you with a robust virtualization environment for your computing needs.

Introduction

KVM has become an essential tool for system administrators, developers, and power users who need to run multiple operating systems simultaneously. It offers near-native performance, excellent stability, and seamless integration with the Linux kernel. By following this guide, you’ll be able to harness the full potential of KVM on your openSUSE system.

Prerequisites

Before diving into the installation process, it’s crucial to ensure your system meets the necessary requirements:

Hardware Requirements

• A 64-bit processor with virtualization support (Intel VT-x or AMD-V)
• Sufficient RAM (at least 4GB, but 8GB or more is recommended)
• Adequate storage space for virtual machine images

Checking for Hardware Virtualization Support

To verify if your CPU supports virtualization:

1. Open a terminal window
2. Run the following command:

egrep -c '(vmx|svm)' /proc/cpuinfo

If the output is 1 or greater, your CPU supports virtualization. If it’s 0, you may need to enable virtualization in your BIOS/UEFI settings.

BIOS/UEFI Settings

If virtualization is not enabled:

1.  your computer
2. Enter the BIOS/UEFI setup (usually by pressing F2, Del, or Esc during boot)
3. Look for options like “Intel Virtualization Technology” or “AMD-V”
4. Enable the virtualization feature
5. Save changes and exit

Preparing the System

Before installing KVM, it’s essential to update your openSUSE system and enable the necessary repositories.

Updating openSUSE

Run the following commands to update your system:

sudo zypper refresh
sudo zypper update

Enabling Required Repositories

KVM packages are typically available in the default openSUSE repositories. However, to ensure you have access to the latest versions, you can add the Virtualization repository:

sudo zypper addrepo https://download.opensuse.org/repositories/Virtualization/openSUSE_Leap_15.5/Virtualization.repo
sudo zypper refresh

Installing Necessary Tools and Packages

Install the required KVM packages using the following command:

sudo zypper install patterns-openSUSE-kvm_server patterns-server-kvm_tools

This command will install the KVM hypervisor, QEMU, libvirt, and other essential tools for managing virtual machines.

Installing KVM on openSUSE

Now that we’ve prepared the system, let’s proceed with the KVM installation.

Using YaST

YaST is openSUSE’s system configuration tool, which provides a user-friendly interface for installing and configuring software.

1. Open YaST by running `sudo yast` in the terminal or by searching for it in the application menu
2. Navigate to “Virtualization” in the left panel
3. Select “Install Hypervisor and Tools” on the right
4. Choose “KVM server” and “KVM tools”
5. Click “Accept” to start the installation

Using Command-line (zypper)

For those who prefer the command line, you can install KVM using zypper:

sudo zypper install qemu-kvm libvirt virt-manager

This command installs the core KVM packages along with libvirt for management and virt-manager for a graphical interface.

Verifying Successful Installation

To ensure KVM was installed correctly:

1. Check if the KVM modules are loaded:

lsmod | grep kvm

2. Verify libvirtd service status:

sudo systemctl status libvirtd

If you see the KVM modules listed and the libvirtd service is active, the installation was successful.

Configuring KVM

After installation, it’s time to configure KVM for optimal performance and security.

Setting up libvirtd Service

Enable and start the libvirtd service:

sudo systemctl enable libvirtd
sudo systemctl start libvirtd

Configuring Network Bridges

Network bridging allows virtual machines to connect directly to the physical network. To set up a bridge:

1. Open YaST Network Settings
2. Add a new bridge device
3. Assign your physical network interface to the bridge
4. Apply the changes and restart the network service

Alternatively, you can use the command line to create a bridge:

sudo nmcli con add type bridge con-name br0 ifname br0
sudo nmcli con add type bridge-slave con-name eth0-slave ifname eth0 master br0
sudo nmcli con up br0

Adjusting Firewall Settings

To allow network traffic for virtual machines:

1. Open YaST Firewall settings
2. Add the “libvirt” service to the list of allowed services
3. Apply the changes

For command-line users:

sudo firewall-cmd --permanent --zone=public --add-service=libvirt
sudo firewall-cmd --reload

Creating Your First Virtual Machine

Now that KVM is installed and configured, let’s create a virtual machine.

Using virt-manager GUI

1. Launch virt-manager by running `virt-manager` in the terminal or from the application menu
2. Click the “Create a new virtual machine” button
3. Choose your installation method (ISO image, network install, etc.)
4. Follow the wizard to configure CPU, memory, and storage settings
5. Complete the installation process

Using Command-line (virt-install)

For those who prefer the command line, you can use virt-install:

sudo virt-install --name myvm --memory 2048 --vcpus 2 --disk size=20 --cdrom /path/to/iso --os-variant opensuse15.5

Adjust the parameters according to your needs.

Choosing and Configuring VM Parameters

When creating a VM, consider the following:

• Allocate sufficient memory and CPU cores
• Choose an appropriate disk size and format (qcow2 is recommended for its features and performance)
• Select the correct OS variant for optimal performance
• Configure networking (NAT or bridged)

Managing KVM Virtual Machines

Once your virtual machines are created, you’ll need to know how to manage them effectively.

Starting and Stopping VMs

Using virt-manager:

• Right-click on the VM and select “Run” or “Shut Down”

Using virsh command-line:

sudo virsh start myvm
sudo virsh shutdown myvm

Accessing VM Console

• In virt-manager, double-click on the running VM to open its console
• For command-line access, use:

sudo virsh console myvm

Modifying VM Settings

• In virt-manager, right-click on the VM and select “Open”
• For command-line modifications, use `virsh edit myvm` to modify the VM’s XML configuration

Performance Tuning

To get the best performance out of your KVM virtual machines, consider the following optimizations:

CPU Pinning

CPU pinning can improve performance by dedicating specific host CPU cores to a VM:

sudo virsh vcpupin myvm 0 0
sudo virsh vcpupin myvm 1 1

This pins vCPU 0 and 1 of the VM to physical CPU cores 0 and 1, respectively.

Memory Allocation Strategies

• Use hugepages to reduce TLB misses and improve performance
• Enable KSM (Kernel Samepage Merging) to save memory:

echo 1 > /sys/kernel/mm/ksm/run

I/O Optimization

• Use virtio drivers for disk and network devices
• Enable cache=none for disk devices to improve write performance
• Consider using a dedicated SSD for VM storage

Troubleshooting Common Issues

Even with careful setup, you may encounter issues. Here are some common problems and their solutions:

Permission Problems

If you encounter permission errors:

• Ensure your user is part of the `libvirt` group:

sudo usermod -aG libvirt $(whoami)

• Check SELinux or AppArmor settings if you’re using them

Network Connectivity Issues

If VMs can’t connect to the network:

• Verify bridge configuration
• Check firewall settings
• Ensure libvirtd service is running

Performance Bottlenecks

For slow VM performance:

• Monitor host resources using `top` or `htop`
• Use `virt-top` to identify resource-hungry VMs
• Adjust VM resource allocation as needed

Advanced KVM Features

As you become more comfortable with KVM, explore these advanced features:

Live Migration

Move running VMs between hosts without downtime:

sudo virsh migrate --live myvm qemu+ssh://destination_host/system

Snapshots and Cloning

Create point-in-time snapshots of VMs:

sudo virsh snapshot-create-as myvm snapshot1

Clone existing VMs:

sudo virt-clone --original myvm --name newvm --auto-clone

PCI Passthrough

Pass physical PCI devices directly to VMs for near-native performance:

1. Enable IOMMU in BIOS and kernel
2. Identify the PCI device
3. Attach the device to the VM using virt-manager or virsh

Security Considerations

Securing your KVM environment is crucial for protecting both host and guest systems.

Isolating VMs

• Use separate networks or VLANs for different VM groups
• Implement strict firewall rules between VMs

Securing the Host System

• Keep the host system updated
• Use strong authentication methods (e.g., SSH keys)
• Implement SELinux or AppArmor for additional security

Regular Updates and Patches

• Set up automatic updates for the host system
• Keep guest OS and applications up-to-date
• Monitor security advisories for KVM and related components

Congratulations! You have successfully installed KVM. Thanks for using this tutorial for installing the Kernel-based Virtual Machine (KVM) on your openSUSE system. For additional or useful information, we recommend you check the official KVM website.