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  1. Home
  3. NetBackup™ Web UI Cloud Administrator's Guide
  5. Recovering cloud assets
  7. Restore to a different cloud provider
  9. Prepare the VMs for back up
NetBackup™ Web UI Cloud Administrator's Guide

Prepare the VMs for back up

This section describes the considerations and prerequisites to back up the VMs for restoring to a different cloud platform. The process is different for different operating systems, depending on the cloud service to which you want to restore.

RHEL

Target: AWS

  1. Install the required Xen and Nitro drivers:

    • If drivers are not installed, then install them by running the following commands:

      • lsinitrd | grep -i -e nvme -e ena -e xen

      • modinfo nvme

        For more information, refer to Install or upgrade the NVMe driver

      • modinfo ena

        For more information, refer to Enable enhanced networking with the Elastic Network Adapter (ENA) on your EC2 instances

      • Update/Create the /etc/dracut.conf file with the following line:

        add_drivers+="xen-blkfront xen-netfront nvme-core nvme"

      • Run the following command:

        dracut -f -v

    • Validate if the drivers are installed successfully by running the following command:

      lsinitrd | grep -i -e nvme -e ena -e xen

  2. To avoid mount failures, it is recommended to replace the device names with UUID in /etc/fstab file.

    Back up the original fstab file and comment out Azure-specific entries, and other non-critical entries which might cause boot failures after restore. Alternatively, you can add nofail in fstab file for these entries.

  3. Create a root user password.
  4. Configure or obtain the root user credentials, if the VM is configured with key based logon.

    To use the key based logon, perform the following:

    • Back up the original /root/.ssh/authorized_keys.

    • The /root/.ssh/authorized_keys contains the same public key as azureuser, but cannot log on using the root user and key due to the following command present in authorized_keys for the root user and the associated key:

      `echo 'Please login as the user \"azureuser\" rather than the user \"root\".';echo;sleep 10;exit 142`

      Note:

      This is applicable for Azure-created keys and user-provided keys.

      You must delete the command to let the root logon work after restore.

    • After editing, the entry appears as follows:

      cat /root/.ssh/authorized_keys
no-port-forwarding,no-agent-forwarding,no-X11-forwarding, ssh-rsa AAAAB3Nza..<truncated>..HruCzDsb3j

Target: Azure

  1. AWS instances have Hv and NVMe drivers preinstalled and hence no additional steps are required. Confirm if the drivers exist in your instance, run the command:

    lsinitrd | grep -i -e hv -e nvme

  2. Replace the device names with UUID in /etc/fstab file.

SLES

Target: AWS

By default, AWS uses SUSE kernel. Hence install the SUSE kernel and select it at the boot time from the GRUB menu on the restored VM as follows:

  1. Refer to the following documentation for more information on entries in zypp.conf file as it may affect the number of kernels retained and their behavior:

    Installing multiple kernel versions

    Proceed with the next steps after ensuring that the SUSE computer can work with multiple kernels.

  2. Run the following command to list the available kernels:

    zypper se -s 'kernel*'

  3. From the list of kernels displayed in the above step, install a suitable default kernel version:

    zypper in kernel-default-<VERSION>

    For example, zypper in kernel-default-5.3.18-53.3

  4. List the installed kernels and kernel modules using the following command:

    zypper se -si 'kernel*'

  5. It is recommended to set a root user password.
  6. If the required drivers are not installed, then install them by running the following commands:

    • lsinitrd --kver <YOUR NEW KERNEL VERSION> | grep xen

    • Update/Create the /etc/dracut.conf file with the following line:

      add_drivers+="xen-blkfront xen-netfront nvme-core nvme"

    • Run the following command:

      dracut -f -v

    • dracut -f -v --kver <YOUR NEW KERNEL VERSION>

    • lsinitrd --kver <YOUR NEW KERNEL VERSION> | grep xen

    <YOUR NEW KERNEL VERSION> is the new kernel version installed in Step 3 above.

  7. Back up the /etc/default/grub file. Edit the original grub file, add GRUB_TIMEOUT and GRUB_TIMEOUT_STYLE entries and comment out the following parameters:

    GRUB_HIDDEN_TIMEOUT

    GRUB_HIDDEN_TIMEOUT_QUIET

    By default, GRUB_DEFAULT is set to 0 in the /etc/default/grub file. Change the default value so that it loads Azure kernel on restart and not the newly installed kernel.

    • For example, GRUB_DEFAULT='1>KERNEL_INDEX' where KERNEL_INDEX can be found with grub2-mkconfig command or by analyzing /boot/grub2/grub.cfg file.

    • Updating GRUB_DEFAULT ensures that the source VM keeps using Azure kernel, in an event, where it is restarted while the new kernel is installed.

    • The GRUB config file has entries similar to the following:

      #GRUB_HIDDEN_TIMEOUT= 
#GRUB_HIDDEN_TIMEOUT_QUIET=true 
GRUB_DEFAULT'1><YOUR KERNEL INDEX NUMBER>' 
GRUB_TIMEOUT=20 
GRUB_TIMEOUT_STYLE=menu

    • Update the GRUB config file using the following command:

      grub2-mkconfig -o /boot/grub2/grub.cfg

    • After restore, to access GRUB menu during restart, press ESC twice during the countdown on EC2 Serial Console.

    For more information on GRUB entries, refer to Simple configuration handling

Target: Azure

  1. Run the following command to verify if the drivers are preinstalled:

    lsinitrd | grep -i -e hv -e nvme

  2. It is recommended to replace the device names with UUID in /etc/fstab file.
Ubuntu

Target: AWS

  1. Run the following command to install the linux-aws kernel package:

    sudo apt-get update && sudo apt-get upgrade -y linux-aws

  2. Change grub countdown style and increase time-out in /etc/default/grub file. This enables the user to enter the recovery mode if issues are faced during the restart:

    GRUB_TIMEOUT_STYLE=menu

    GRUB_TIMEOUT=20

  3. To avoid loading the new kernel on restart, ensure that the default kernel entry (GRUB_DEFAULT) in the grub configuration file is pointing to Azure-specific kernel and not the newly installed kernel.
  4. Run the following command to update grub file:

    update-grub

Target: Azure

  1. Run the following command to verify if the drivers are preinstalled:

    lsinitrd | grep -i -e hv -e nvme

  2. It is recommended to replace the device names with UUID in /etc/fstab file.

Windows

Target: AWS

  1. Check the boot mode (Legacy or UEFI).
  2. Run the following:

    (Ctrl + R) -> MSInfo32.exe → BIOS Mode

  3. Install the following drivers:

    • PV driver: AWSPVDriver.zip

    • EC2 install: EC2Install.zip

    • NVME: AWSNVMe.zip

    • ENA: AwsEnaNetworkDriver.zip

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