Chapitre 2. Enabling virtualization

To use virtualization in RHEL 9, you must install virtualization packages and ensure your system is configured to host virtual machines (VMs). The specific steps to do this vary based on your CPU architecture.

2.1. Enabling virtualization on AMD64 and Intel 64

To set up a KVM hypervisor and create virtual machines (VMs) on an AMD64 or Intel 64 system running RHEL 9, follow the instructions below.

Conditions préalables

  • Red Hat Enterprise Linux 9 is installed and registered on your host machine.
  • Your system meets the following hardware requirements to work as a virtualization host:

    • The architecture of your host machine supports KVM virtualization.
    • The following minimum system resources are available:

      • 6 GB free disk space for the host, plus another 6 GB for each intended VM.
      • 2 GB of RAM for the host, plus another 2 GB for each intended VM.

Procédure

  1. Install the virtualization hypervisor packages.

    # dnf install qemu-kvm libvirt virt-install virt-viewer
  2. Start the virtualization services:

    # for drv in qemu network nodedev nwfilter secret storage interface; do systemctl start virt${drv}d{,-ro,-admin}.socket; done

Vérification

  1. Verify that your system is prepared to be a virtualization host:

    # virt-host-validate
    [...]
    QEMU: Checking for device assignment IOMMU support         : PASS
    QEMU: Checking if IOMMU is enabled by kernel               : WARN (IOMMU appears to be disabled in kernel. Add intel_iommu=on to kernel cmdline arguments)
    LXC: Checking for Linux >= 2.6.26                          : PASS
    [...]
    LXC: Checking for cgroup 'blkio' controller mount-point    : PASS
    LXC: Checking if device /sys/fs/fuse/connections exists    : FAIL (Load the 'fuse' module to enable /proc/ overrides)
  2. If all virt-host-validate checks return a PASS value, your system is prepared for creating VMs.

    If any of the checks return a FAIL value, follow the displayed instructions to fix the problem.

    If any of the checks return a WARN value, consider following the displayed instructions to improve virtualization capabilities.

Résolution de problèmes

  • If KVM virtualization is not supported by your host CPU, virt-host-validate generates the following output:

    QEMU: Checking for hardware virtualization: FAIL (Only emulated CPUs are available, performance will be significantly limited)

    However, VMs on such a host system will fail to boot, rather than have performance problems.

    To work around this, you can change the <domain type> value in the XML configuration of the VM to qemu. Note, however, that Red Hat does not support VMs that use the qemu domain type, and setting this is highly discouraged in production environments.