# Preparing UNIX VMs with Oracle Linux 8, RHEL 8, and Later for Conversion to VMware Cloud Director

Before restoring a UNIX-based virtual machine (VM) to VMware Cloud Director, specific preparatory steps are required to ensure a successful conversion and power-on. All necessary steps are described below, including an important additional step for Oracle Linux 8, RHEL 8, and later versions to ensure the vmw_pvscsi driver remains persistently loaded.

## Applies To

- Oracle Linux 8 and later

- RHEL 8 and later

## Overview

During the VM conversion process to VMware Cloud Director, certain SCSI drivers, especially vmw_pvscsi, must be available in the initial RAM disk (initrd) or built into the kernel. Without these, the converted VMs will fail to boot.

## Procedure

1. Check if vmw_pvscsi is built into the kernel. Check the kernel configuration by running the following command:

       grep -i pvscsi /boot/config-$(uname -r)

   Interpret the output as follows:

   - If it contains CONFIG_SCSI_VMW_PVSCSI=y, then the driver is built into the kernel. No further action is needed.

   - If it shows CONFIG_SCSI_VMW_PVSCSI=m, the driver is a module and must be included in the initrd.

2. Check if vmw_pvscsi is in the initrd. Run the following command:

       lsinitrd | grep -i vmw_pvscsi

   If no output is returned, the module is not included in the initrd and must be added.

3. Ensure the vmw_pvscsi driver is persistently loaded. Run the following command to persist the module across reboots:

       echo "vmw_pvscsi" | sudo tee /etc/modules-load.d/vmw_pvscsi.conf

   This ensures that the vmw_pvscsi module is loaded every time the system boots.

4. Rebuild the initrd image as follows:

   1. Make a backup of your existing initrd by running the following command:

           cp /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r)-backup.img

   2. Rebuild the initrd with the required driver by running the following command:

          dracut --force --add-drivers "vmw_pvscsi" -v

      Alternatively, regenerate all initrd images (not usually required unless you need full regeneration) by running the following command:

          dracut --force --regenerate-all

      Or for the current kernel only:

          dracut -f /boot/initramfs-$(uname -r).img $(uname -r)

5. Verify vmw_pvscsi is in the rebuilt initrd by running the following command:

       lsinitrd | grep -i vmw_pvscsi

   The output will confirm that the driver is included.

6. Reboot the VM running the following command:

       reboot

7. After the VM reboots, verify that the vmw_pvscsi module is loaded by running the following command:

       lsmod | grep vmw_pvscsi

   The output will indicate that the module is loaded.

## Other Important Considerations

- Ensure DHCP is configured for the source VM. Static IPs are not retained during conversion.

- For Linux VMs, the failure to load required drivers such as vmw_pvscsi will prevent the VM from booting in VMware Cloud Director.

- For Azure VMs, do the following:

  - Ensure that Windows VMs have the pagefile enabled on the C: drive.

  - Ensure that Linux VMs have fstab entries using UUIDs, not disk names.

## Post-Conversion Actions

- You may need to manually update disk assignments, especially for UEFI-booted systems or when multiple disk controller types are used.

- VMware Tools is not automatically installed. Use the vSphere client to install them after conversion.

- Disks for Windows VMs may be offline post-conversion. Bring them online manually.

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