Create a btrfs data disk with Azure + Packer

{
  "execute_command": "chmod +x {{ .Path }}; {{ .Vars }} sudo -E sh '{{ .Path }}'",
  "inline": [
    // Print all the block "sd*" block devices (for visual debugging if necessary)
    "lsblk -o NAME,HCTL,SIZE,MOUNTPOINT | grep -i \"sd\"",
    // Use the size of your DATA disk, specified in your packer's `disk_additional_size`, as a key for this grep.
    // Ensure only one block device is expected to be this size!
    "DEVICE=$(lsblk -o NAME,HCTL,SIZE,MOUNTPOINT | grep -i \"sd\" | grep \"128\" | cut -d' ' -f1)",
    "echo \"DEVICE FOUND = $DEVICE\"",
    // Ensure the btrfs module is loaded
    "modprobe btrfs",
    // Make filesystem over the entire block device (no need to partition, like with other filesystems)
    "mkfs.btrfs /dev/$DEVICE -f",
    // Make a directory to mount into. I call it butter
    "mkdir /butter",
    // Mount your directory
    "mount /dev/$DEVICE /butter",
    // Do this so that blkid will pick up the right UUID
    "partprobe /dev/$DEVICE",
    "blkid",
    "UUID=$(blkid | grep \"$DEVICE\" | cut -d' ' -f2 | cut -d\\\" -f2)",
    "echo \"UUID = $UUID\"",
    // You'll need this entry in your /etc/fstab for the device to get remounted again.
    "echo \"UUID=$UUID   /butter   btrfs   defaults,nofail   1   2\" >> /etc/fstab",
    // Overkill on the permissions for this example :')
    "chmod -R 777 /butter",
    // Some output sanity checks
    "df -khT",
    "mount | grep \"/dev\""
  ],
  "inline_shebang": "/bin/bash -xe",
  "type": "shell"
}

{
  "variables": {
    "image_version": "0.0.1",
    "rg": "YOUR_RG"
  },
  "builders": [
    {
      "type": "azure-arm",
      "use_azure_cli_auth": true,
      "os_type": "Linux",
      "os_disk_size_gb": 32,
      "image_publisher": "Canonical",
      "image_offer": "UbuntuServer",
      "image_sku": "18.04-LTS",
      "build_resource_group_name": "{{user `rg`}}",
      "managed_image_resource_group_name": "{{user `rg`}}",
      "managed_image_name": "local-packer",
      "managed_image_storage_account_type": "Premium_LRS",
      "vm_size": "Standard_DS2_v2",
      "disk_additional_size": [128],
      "azure_tags": {
        "localversion": "{{user `image_version`}}"
      },
      "shared_image_gallery_destination": {
        "resource_group": "{{user `rg`}}",
        "gallery_name": "local_shared_image_gallery",
        "image_name": "local-packed",
        "image_version": "{{user `image_version`}}",
        "replication_regions": ["West US 2"]
      }
    }
  ],
  "provisioners": [
    {
      "execute_command": "chmod +x {{ .Path }}; {{ .Vars }} sudo -E sh '{{ .Path }}'",
      "inline": [
        "export DEBIAN_FRONTEND=noninteractive",
        "apt-get update",
        "apt-get upgrade -y",
        "apt-get install -y jq dirmngr gnupg apt-transport-https ca-certificates",
        "echo \"deb [arch=amd64] https://packages.microsoft.com/repos/azure-cli/ $(lsb_release -cs) main\" > /etc/apt/sources.list.d/azure-cli.list",
        "curl -sL https://packages.microsoft.com/keys/microsoft.asc | (OUT=$(apt-key add - 2>&1) || echo $OUT)",
        "apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF",
        "'echo \"deb https://download.mono-project.com/repo/ubuntu stable-bionic main\" > /etc/apt/sources.list.d/mono-official-stable.list'",
        "apt-get update",
        "apt-get install -y azure-cli mono-complete",
        "mono --version",
        "az --version",
        "DISTRO=$(lsb_release -is | tr '[:upper:]' '[:lower:]')",
        "CODENAME=$(lsb_release -cs)",
        "curl -s https://packages.microsoft.com/keys/microsoft.asc | (OUT=$(apt-key add - 2>&1) || echo $OUT)",
        "echo \"deb [arch=amd64] https://packages.microsoft.com/repos/microsoft-${DISTRO}-${CODENAME}-prod ${CODENAME} main\" > /etc/apt/sources.list.d/microsoft.list",
        "apt-get update",
        "apt-get -y install --no-install-recommends moby-cli moby-engine",
        "LATEST_COMPOSE_VERSION=$(curl -sSL \"https://api.github.com/repos/docker/compose/releases/latest\" | grep -o -P '(?<=\"tag_name\": \").+(?=\")')",
        "curl -sSL \"https://github.com/docker/compose/releases/download/${LATEST_COMPOSE_VERSION}/docker-compose-$(uname -s)-$(uname -m)\" -o /usr/local/bin/docker-compose",
        "chmod +x /usr/local/bin/docker-compose",
        "wget https://dot.net/v1/dotnet-install.sh",
        "chmod +x ./dotnet-install.sh",
        "apt-get install -y dotnet-sdk-3.1",
        "./dotnet-install.sh  -v 3.1.404 --install-dir /usr/share/dotnet"
      ],
      "inline_shebang": "/bin/sh -xe",
      "type": "shell"
    },
    {
      "execute_command": "chmod +x {{ .Path }}; {{ .Vars }} sudo -E sh '{{ .Path }}'",
      "inline": [
        "lsblk -o NAME,HCTL,SIZE,MOUNTPOINT | grep -i \"sd\"",
        "DEVICE=$(lsblk -o NAME,HCTL,SIZE,MOUNTPOINT | grep -i \"sd\" | grep \"128\" | cut -d' ' -f1)",
        "echo \"DEVICE FOUND = $DEVICE\"",
        "modprobe btrfs",
        "mkfs.btrfs /dev/$DEVICE -f",
        "mkdir /butter",
        "mount /dev/$DEVICE /butter",
        "partprobe /dev/$DEVICE",
        "blkid",
        "UUID=$(blkid | grep \"$DEVICE\" | cut -d' ' -f2 | cut -d\\\" -f2)",
        "echo \"UUID = $UUID\"",
        "echo \"UUID=$UUID   /butter   btrfs   defaults,nofail   1   2\" >> /etc/fstab",
        "chmod -R 777 /butter",
        "df -khT",
        "mount | grep \"/dev\""
      ],
      "inline_shebang": "/bin/bash -xe",
      "type": "shell"
    },
    // ...ANY OTHER PROVISIONERS YOU WANT HERE...
    // ...
    {
      "execute_command": "chmod +x {{ .Path }}; {{ .Vars }} sudo -E sh '{{ .Path }}'",
      "inline": [
        "/usr/sbin/waagent -force -deprovision+user && export HISTSIZE=0 && sync"
      ],
      "inline_shebang": "/bin/sh -xe",
      "type": "shell"
    }
  ]
}