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How to Import a RedHat / RHEL / CentOS based VM#

Overview#

Key Points

  • Redhat/CentOS installs drivers only for the detected hardware during installation.
  • Imported VMs may fail to boot due to missing drivers for new hardware.
  • You can resolve these boot issues by adjusting hardware configuration and regenerating the initramfs.

This guide explains how to import Redhat/CentOS based virtual machines from other hypervisors into VergeOS. It addresses potential problems like VMs not booting or lacking network connectivity after migration.

Prerequisites#

  • Access to VergeOS and the VergeOS UI.
  • Familiarity with the hypervisor environment and VM configuration.
  • Imported VM files must be present in the VergeOS environment.

Steps#

1. Update VM Hardware Configuration#

  1. Change all hard drives to virtio-scsi:

    • In the VergeOS UI, navigate to the VM's settings.
    • For each hard drive, change the interface to virtio-scsi for optimal performance and compatibility.

  2. Change all NICs to virtio:

    • Ensure that all network interface cards (NICs) are set to virtio for enhanced networking support.

  3. Adjust Boot Order:

    • Make sure that the OS disk is listed as ID 0 in the boot order.

2. Boot into Rescue Mode#

  1. Start the VM:

    • Power on the VM, and during boot, hold the Left Shift key to access the GRUB boot menu.

  2. Select Rescue Mode:

    • In the GRUB menu, select the rescue mode to boot into a minimal recovery environment.

3. Rebuild Initramfs#

  1. Log into the Terminal:

    • Once in rescue mode, access the terminal via the VM console.

  2. Regenerate Initramfs:

    • Run the following command to regenerate the initramfs with the necessary drivers: 
      sudo dracut -f --regenerate-all --add-drivers "virtio_blk virtio_net"
    • This command adds drivers for virtio_blk (block device) and virtio_net (network device) to the initramfs, allowing the VM to boot with the correct drivers for VergeOS.

4. Reboot and Verify#

  1. Reboot the VM:

    • After regenerating the initramfs, reboot the VM by running: 
      reboot

  2. Verify Boot and Network Connectivity:

    • Confirm that the VM boots successfully and that network connectivity is functional via the virtio NIC.

Troubleshooting#

Common Issues

  • VM is not booting:
  • Solution: Double-check the boot order in the VM settings. The OS disk must be set as ID 0.
  • No network connectivity:
  • Solution: Ensure that NICs are set to virtio and that the initramfs was rebuilt with the appropriate network drivers.

Additional Resources#

Feedback#

Need Help?

If you have any questions or encounter issues while importing a VM, please reach out to our support team for assistance.

Document Information

  • Last Updated: 2024-09-09
  • VergeOS Version: 4.12.6