Manually Moving a Guest to a Different KVM Host

6.18 Manually Moving a Guest to a Different KVM Host

You can manually move an Oracle Linux KVM guest to a different KVM host.

The target Oracle Exadata KVM host must meet the following requirements:

The target KVM host must have the same Oracle Exadata System Software release installed with Oracle Linux KVM.
The target KVM host must reside in the same Exadata system configuration and have the same network visibility.
The target KVM host must have access to the same Oracle Exadata storage servers.
The target KVM host must have sufficient free resources (CPU, memory, and local disk storage) to operate the guest.
- It is possible to over-commit virtual CPUs such that the total number of virtual CPUs assigned to all domains exceeds the number of physical CPUs on the system. Over-committing CPUs can be done only when the competing workloads for over-subscribed resources are well understood and the concurrent demand does not exceed physical capacity.
- It is not possible to over-commit memory.
- Copying disk images to the target KVM host may increase space allocation of the disk image files because the copied files are no longer able to benefit from the disk space savings gained by using reflinks.
The guest name must not be already in use on the target KVM host.

The following procedure moves a guest to another KVM host.

In the KVM host, shut down the guest that is being moved.
```
# vm_maker --stop-domain GuestName
```
Copy the guest disk image and configuration files to the target KVM host.
In the following examples, replace GuestName with the name of the guest, and replace target with the host name of the target KVM host.
```
# scp -r /EXAVMIMAGES/GuestImages/GuestName/ target:/EXAVMIMAGES/GuestImages
```

Copy the guest XML definition to the target KVM host.

# scp /etc/libvirt/qemu/GuestName.xml target:/EXAVMIMAGES/GuestImages

In the target KVM host, define the domain.

# virsh define /EXAVMIMAGES/GuestImages/GuestName.xml

If you are using Oracle Exadata System Software release 20.1 or later, run the following vm_maker command in the target KVM host to complete the guest migration.
```
# vm_maker --update-mac GuestName
```
Note:
- The vm_maker --update-mac command is first introduced in Oracle Exadata System Software release 20.1.4 (November 2020). If you are using an earlier 20.1 release, you must perform an update to get this command.
- This step is not required on systems using a release of Oracle Exadata System Software prior to 20.1.
Start the migrated guest on the target KVM host.
```
# vm_maker --start-domain GuestName
```

Parent topic: Managing Oracle Linux KVM Guests