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Prepare an Ubuntu virtual machine for Azure

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Applies to: ✔️ Linux VMs ✔️ Flexible scale sets

Ubuntu now publishes official Azure virtual hard disks (VHDs) for download at the Ubuntu Cloud Images webpage. If you need to build your own specialized Ubuntu image for Azure instead of using the manual procedure that follows, start with these known working VHDs and customize them, as needed. You can always find the latest image releases at the following locations:

Prerequisites

This article assumes that you've already installed an Ubuntu Linux operating system (OS) to a VHD. Multiple tools exist to create .vhd files. An example is a virtualization solution such as Hyper-V. For instructions, see Install the Hyper-V role and configure a virtual machine (VM).

Ubuntu installation notes

  • For more tips on preparing Linux for Azure, see General Linux installation notes.
  • The VHDX format isn't supported in Azure, only fixed VHD. You can convert the disk to VHD format by using Hyper-V Manager or the Convert-VHD cmdlet.
  • When you install the Linux system, we recommend that you use standard partitions rather than Logical Volume Manager (LVM), which is often the default for many installations. These standard partitions avoid LVM name conflicts with cloned VMs, particularly if an OS disk ever needs to be attached to another VM for troubleshooting. LVM or RAID can also be used on data disks.
  • Don't configure a swap partition or swap file on the OS disk. You can configure the cloud-init provisioning agent to create a swap file or a swap partition on the temporary resource disk. For more information about this process, see the following steps.
  • All VHDs on Azure must have a virtual size aligned to 1 MB. When you convert from a raw disk to VHD, you must ensure that the raw disk size is a multiple of 1 MB before conversion. For more information, see Linux installation notes.

Manual steps

Note

Before you attempt to create your own custom Ubuntu image for Azure, consider using the prebuilt and tested images from the Ubuntu Cloud Images webpage instead.

  1. In the center pane of Hyper-V Manager, select the VM.

  2. Select Connect to open the window for the VM.

  3. Replace the current repositories in the image to use Ubuntu's Azure repository.

    Before you edit /etc/apt/sources.list, we recommend that you make a backup:

    sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak

    sudo sed -i 's#http://archive\.ubuntu\.com/ubuntu#http://azure\.archive\.ubuntu\.com/ubuntu#g' /etc/apt/sources.list
sudo sed -i 's#http://[a-z][a-z]\.archive\.ubuntu\.com/ubuntu#http://azure\.archive\.ubuntu\.com/ubuntu#g' /etc/apt/sources.list
sudo sed -i 's#http://security\.ubuntu\.com/ubuntu#http://azure\.archive\.ubuntu\.com/ubuntu#g' /etc/apt/sources.list
sudo sed -i 's#http://[a-z][a-z]\.security\.ubuntu\.com/ubuntu#http://azure\.archive\.ubuntu\.com/ubuntu#g' /etc/apt/sources.list
sudo apt-get update

  4. The Ubuntu Azure images are now using the Azure-tailored kernel. Update the OS to the latest Azure-tailored kernel and install Azure Linux tools (including Hyper-V dependencies):

    sudo apt update
sudo apt install linux-azure linux-image-azure linux-headers-azure linux-tools-common linux-cloud-tools-common linux-tools-azure linux-cloud-tools-azure
sudo apt full-upgrade
sudo reboot

  5. Modify the kernel boot line for GRUB to include extra kernel parameters for Azure. To do this step, open /etc/default/grub in a text editor, find the variable called GRUB_CMDLINE_LINUX_DEFAULT (or add it if needed), and edit it to include the following parameters:

    GRUB_CMDLINE_LINUX_DEFAULT="console=tty1 console=ttyS0,115200n8 earlyprintk=ttyS0,115200 rootdelay=300 quiet splash"

  6. Save and close this file, and then run sudo update-grub. This step ensures that all console messages are sent to the first serial port, which can assist Azure technical support with debugging issues.

  7. Ensure that the SSH server is installed and configured to start at boot time. This setting is usually the default.

  8. Install cloud-init (the provisioning agent) and the Azure Linux agent (the guest extensions handler). Cloud-init uses netplan to configure the system network configuration (during provisioning and each subsequent boot) and gdisk to partition resource disks.

    sudo apt update
sudo apt install cloud-init gdisk netplan.io walinuxagent && systemctl stop walinuxagent

    Note

    The walinuxagent package might remove the NetworkManager and NetworkManager-gnome packages, if they're installed.

  9. Remove cloud-init default configurations and leftover netplan artifacts that might conflict with cloud-init provisioning on Azure:

    sudo rm -f /etc/cloud/cloud.cfg.d/50-curtin-networking.cfg /etc/cloud/cloud.cfg.d/curtin-preserve-sources.cfg /etc/cloud/cloud.cfg.d/99-installer.cfg /etc/cloud/cloud.cfg.d/subiquity-disable-cloudinit-networking.cfg
sudo rm -f /etc/cloud/ds-identify.cfg
sudo rm -f /etc/netplan/*.yaml

  10. Configure cloud-init to provision the system by using the Azure data source:

    sudo tee /etc/cloud/cloud.cfg.d/90_dpkg.cfg <<EOF
datasource_list: [ Azure ]
EOF

sudo tee /etc/cloud/cloud.cfg.d/90-azure.cfg <<EOF
system_info:
   package_mirrors:
     - arches: [i386, amd64]
       failsafe:
         primary: http://archive.ubuntu.com/ubuntu
         security: http://security.ubuntu.com/ubuntu
       search:
         primary:
           - http://azure.archive.ubuntu.com/ubuntu/
         security: []
     - arches: [armhf, armel, default]
       failsafe:
         primary: http://ports.ubuntu.com/ubuntu-ports
         security: http://ports.ubuntu.com/ubuntu-ports
EOF

sudo tee /etc/cloud/cloud.cfg.d/10-azure-kvp.cfg <<EOF
reporting:
  logging:
    type: log
  telemetry:
    type: hyperv
EOF

  11. Configure the Azure Linux agent to rely on cloud-init to perform provisioning. For more information on these options, look at the WALinuxAgent project.

    sudo sed -i 's/Provisioning.Enabled=y/Provisioning.Enabled=n/g' /etc/waagent.conf
sudo sed -i 's/Provisioning.UseCloudInit=n/Provisioning.UseCloudInit=y/g' /etc/waagent.conf
sudo sed -i 's/ResourceDisk.Format=y/ResourceDisk.Format=n/g' /etc/waagent.conf
sudo sed -i 's/ResourceDisk.EnableSwap=y/ResourceDisk.EnableSwap=n/g' /etc/waagent.conf

    sudo tee -a /etc/waagent.conf <<EOF
# For Azure Linux agent version >= 2.2.45, this is the option to configure,
# enable, or disable the provisioning behavior of the Linux agent.
# Accepted values are auto (default), waagent, cloud-init, or disabled.
# A value of auto means that the agent will rely on cloud-init to handle
# provisioning if it is installed and enabled, which in this case it will.
Provisioning.Agent=auto
EOF

  12. Clean cloud-init and Azure Linux agent runtime artifacts and logs:

    sudo cloud-init clean --logs --seed
sudo rm -rf /var/lib/cloud/
sudo systemctl stop walinuxagent.service
sudo rm -rf /var/lib/waagent/
sudo rm -f /var/log/waagent.log

  13. Deprovision the VM and prepare it for provisioning on Azure.

    Note

    The sudo waagent -force -deprovision+user command generalizes the image by attempting to clean the system and make it suitable for reprovisioning. The +user option deletes the last provisioned user account and associated data.

    sudo waagent -force -deprovision+user
sudo rm -f ~/.bash_history

    Warning

    Deprovisioning by using the preceding command doesn't guarantee that the image is cleared of all sensitive information and is suitable for redistribution.

  14. Select Action > Shut Down in Hyper-V Manager.

  15. Azure only accepts fixed-size VHDs. If the VM's OS disk isn't a fixed-size VHD, use the Convert-VHD PowerShell cmdlet and specify the -VHDType Fixed option. For more information, look at the docs for Convert-VHD at Convert-VHD.

  16. To bring a Generation 2 VM on Azure, follow these steps:

    1. Change the directory to the boot EFI directory:

      cd /boot/efi/EFI

    2. Copy the ubuntu directory to a new directory named boot:

      sudo cp -r ubuntu/ boot

    3. Change the directory to the newly created boot directory:

      cd boot

    4. Rename the shimx64.efi file:

      sudo mv shimx64.efi bootx64.efi

    5. Rename the grub.cfg file to bootx64.cfg:

      sudo mv grub.cfg bootx64.cfg

Related content

You're now ready to use your Ubuntu Linux VHD to create new VMs in Azure. If this is the first time that you're uploading the .vhd file to Azure, see Create a Linux VM from a custom disk.