Switch KVM Stacks

You can switch from one KVM stack to another KVM stack, if required.

The KVM stacks define the versions of user space packages that you can use to manage virtual machines on Oracle Linux. To take advantage of newer functionality available in more recent user space packages, you must install UEK.

The Default KVM stack is compatible with both RHCK and UEK. The Default KVM stack is available from the standard Oracle Linux package repositories. If you require RHCK, you can only use the Default KVM stack.

The Oracle KVM stack, which includes more KVM features than the default stack, requires UEK to be running on the host system and that the ol8_kvm_appstream yum repository is enabled on the system.

Switching the KVM stack on an Oracle Linux system involves removing one version of the KVM stack and then replacing it with another version of the KVM stack.

Caution:

Guest instances that were created by using one KVM stack might not be compatible and might not start after switching to another KVM stack.

For instructions on how to switch KVM stacks on Oracle Linux 8 systems with UEK, see these topics:

Note:

For details about the KVM stacks and their sources, see Virtualization Package Sources.

Switch Default Stack to Oracle KVM Stack

The following information describes how Oracle Linux 8 users can switch from the Default KVM stack to the Oracle KVM stack.

Ensure that the following are true before proceeding:

  • The Oracle Linux 8 system has the Default KVM stack packages installed.
  • The host system must be running the latest UEK R6 or UEK R7 .
  • You have administrator privileges.

Caution:

Guest instances that were created using the default KVM stack might not be compatible and might not start after switching to the Oracle KVM stack.
Follow these steps to switch from the Default KVM stack to the Oracle KVM Stack.
  1. Remove any packages from the existing default virt module stream: 
    sudo dnf module remove virt -y --all

    Note:

    Oracle Linux 8 virtualization stacks are managed by switching between application streams for the virt module. For more information about using DNF modules and application streams, see Oracle Linux: Managing Software on Oracle Linux
  2. Reset the virt module state so that it's neither enabled nor disabled: 
    sudo dnf module reset virt -y
  3. Enable the ol8_kvm_appstream yum repository.
    For more information, see Enable Yum Repositories.
  4. Enable the appropriate module and stream. For example, to use the latest packages: 
    sudo dnf module enable virt:kvm_utils3 -y
  5. Perform any necessary package upgrade or downgrade operations to handle dependencies for the enabled module and stream:
    sudo dnf --allowerasing distro-sync
  6. Install the base packages from the appropriate module and stream. For example, to use the latest packages: 
    sudo dnf module install virt:kvm_utils3 -y

Switch Oracle KVM Stack to Default Stack

The following information describes how Oracle Linux 8 users can switch from the Oracle KVM stack to the Default KVM stack.

Ensure that the following are true before proceeding:

  • The Oracle Linux 8 system has the Oracle KVM stack module and stream installed.
  • The host system is running the latest UEK R6 or UEK R7 .
  • You have administrator privileges.

Caution:

Guest instances that were created using the Oracle KVM stack might not be compatible and might not start after switching to the Default KVM stack.
Follow these steps to switch from the Oracle KVM stack to the Default KVM stack.
  1. Remove any of the packages from the existing Oracle KVM stack module stream, for example: 
    sudo dnf module remove virt:kvm_utils3 -y --all

    Note:

    Oracle Linux 8 virtualization stacks are managed by switching between application streams for the virt module. For more information about using DNF modules and application streams, see Oracle Linux: Managing Software on Oracle Linux.
  2. Reset the virt module state so that it's neither enabled nor disabled: 
    sudo dnf module reset virt -y
  3. Enable the virt module and stream: 
    sudo dnf module enable virt -y
  4. Perform any necessary package upgrade or downgrade operations to handle dependencies for the enabled module and stream:
    sudo dnf --allowerasing distro-sync
  5. Install the base packages from the virt stream: 
    sudo dnf module install virt -y
  6. Disable the ol8_kvm_appstream yum repository:
    sudo dnf config-manager --disable ol8_kvm_appstream
    If you don't intend to use the Oracle KVM stack, disabling the associated repository prevents installation of packages from that repository in the future and ensures compatibility between installed KVM components.

Upgrade the Oracle KVM Stack

The following information describes how Oracle Linux 8 users can upgrade Oracle KVM stack packages to the latest version of the Oracle KVM stack by switching module streams.

Ensure that the following are true before proceeding:

  • You have an Oracle Linux 8 system with an earlier Oracle KVM stack stream installed.
  • The host system is running the latest UEK R6 or UEK R7.
  • You have administrator privileges.

Caution:

Guest instances that were created using an earlier Oracle KVM stack stream might not be compatible and might not start after switching to the later version of the Oracle KVM stack.

Follow these steps to switch from an earlier Oracle KVM stack stream to the latest version of the Oracle KVM stack.

  1. Remove any of the packages from the existing Oracle KVM stack.

    For example, to switch from the virt:kvm_utils2 module stream: 

    sudo dnf module remove virt:kvm_utils2 -y --all

    Note:

    Oracle Linux 8 virtualization stacks are managed by switching between application streams for the virt module. For more information about using DNF modules and application streams, see Oracle Linux: Managing Software on Oracle Linux.
  2. Reset the virt module state so that it's neither enabled nor disabled: 
    sudo dnf module reset virt -y
  3. Enable the latest module and stream.

    For example, to enable virt:kvm_utils3: 

    sudo dnf module enable virt:kvm_utils3 -y
  4. Perform any necessary package upgrade or downgrade operations to handle dependencies required for the enabled module and stream:
    sudo dnf --allowerasing distro-sync
  5. Install the later version of the Oracle KVM stack packages.

    For example, to install the packages from virt:kvm_utils3: 

    sudo dnf module install virt:kvm_utils3 -y