VM Offer

Publishing a VM Offer

Contents

Virtual Machine offers are used to deploy and transact a virtual machine (VM) instance through Marketplace. The solution must consist of a single VM. Anything more complex requires an Azure Apps offer.

When a customer ‘purchases’ a VM offer, the VM will be deployed into the customer’s Azure subscription. As a consequence, VM offers can only be published in Azure Marketplace (not AppSource).

VM offers support the Transact listing type. They also support the BYOL listing type. A Test drive option is also available.

Transact VM offers are billed on a usage-based PAYG (Pay As You Go) model. Each plan can be created with a free trial option giving you the option to offer customers a 1 / 3 / 6 month period with no licence fees.

Prerequisites

Overview

In this lab we will create the technical assets required to publish a VM offer to the commercial marketplace. The high level steps required to do this are as follows:

Create a VM to use as a base

We will create a VM using an approved base image. However it is also possible to create and deploy your own VM image. Starting from an approved base image simplifies the process.

There are numerous way we could create the VHD. In this lab we will use the Azure CLI. Packer is a useful tool for helping to automate the process.

Create a VM using the Azure CLI

  1. Create a new resource group using the Azure CLI:

    az group create --name 'marketplace-vm-offer' --location 'westeurope'
    

    Example output

       {
          "id": "/subscriptions/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourceGroups/marketplace-vm-offer",
          "location": "westeurope",
          "managedBy": null,
          "name": "marketplace-vm-offer",
          "properties": {
             "provisioningState": "Succeeded"
          },
          "tags": null,
          "type": "Microsoft.Resources/resourceGroups"
       }
    
  2. Create the VM

    We will create an Ubuntu VM using a small machine size to minimise costs. It is important to create a VM using unmanaged disks as the base. This gives us direct access to the VHD which we will need to copy at a later stage. Generating ssh keys gives us a simple, secure way to connect to the VM.

    Create a new VM using the Azure CLI:

    az vm create \
       --resource-group 'marketplace-vm-offer' \
       --name 'marketplacevm' \
       --image 'Canonical:UbuntuServer:18.04-LTS:latest' \
       --admin-username 'azureuser' \
       --generate-ssh-keys \
       --size 'Standard_B1s' \
       --use-unmanaged-disk
    

    Example output

       {
          "id": "/subscriptions/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourceGroups/marketplace-vm-offer/providers/Microsoft.Compute/virtualMachines/marketplacevm",
          "location": "westeurope",
          "macAddress": "00-0D-3A-20-E4-73",
          "powerState": "VM running",
          "privateIpAddress": "10.0.0.4",
          "publicIpAddress": "13.93.33.158",
          "resourceGroup": "marketplace-vm-offer",
          "zones": ""
       }
    

Ensure the VM has latest updates applied

Before publishing VM offer you must ensure you have updated the OS and all installed services with the latest security and maintenance patches.

  1. Firstly we have to connect to the VM using ssh.

    Use the publicIpAddress returned in the output above. This will use the private key file id_rsa stored in ~/.ssh to authenticate:

    ssh azureuser@13.93.44.158
    
  2. Run the following commands on the VM to install the latest updates:

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

Perform additional security checks

When you publish a VM offer to the Azure Marketplace, you are required to maintain a high-level of security. Before publishing an offer you should follow the guidance in Security Recommendations for Azure Marketplace Images

As we are only publishing a test and will not put this “live” into the marketplace we will skip these additional checks for the purposes of this lab.

Apply custom configuration and scheduled tasks as required

To simulate a real workload, we will add a web server and a startup task to our VM offer.

  1. To install the NGINX web server, run the following command in the VM:

    sudo apt-get -y install nginx
    
  2. We will also add a scheduled job to run whenever the VM reboots. Edit the root crontab file as follows:

    sudo crontab -e
    
  3. Add the following line at the end of the file:

    @reboot less /etc/passwd > /tmp/users.txt
    
  4. Save and exit the file.

    This will illustrate the use of a scheduled job by dumping the names of all user accounts to a file in the /tmp directory each time the VM reboots.

    When we test our VM we will be able to confirm the webserver displays a default page and there is a file called users.txt in the /tmp directory containing the names of all users including the admin username we specified on creation.

Generalise the image

To create a reusable image, the operating system disk must be generalised. For Linux VMs this involves removing the Azure Linux agent and stopping the VM.

  1. Remove the Azure Linux agent by entering the following command

    sudo waagent -verbose -deprovision+user
    
  2. Confirm the removal

  3. Exit the SSH session in the VM by typing exit

  4. Stop and de-allocate the VM. Run the following command.

    az vm deallocate \
       --resource-group 'marketplace-vm-offer' \
       --name 'marketplacevm'
    

We now have a generalised OS VHD for our Ubuntu-based VM offer with a web server installed and a scheduled job on reboot. We can use this VHD image to create new (specialised) VMs.

Test the virtual machine image

The first and simplest test is to confirm that we can create a new VM instance based on the VHD we created above. The following is based on the instructions Test a virtual machine image but with some modifications as I have found the provided script not to work for Linux images.

  1. Sign in to the Azure portal.

  2. On the home page, select Create a resource, search for “Template Deployment”, and select Create.

  3. Choose “Build your own template in the editor”.

    Create VM from ARM Template

  4. Copy and paste the JSON from this file into the editor and hit Save

  5. You will need to provide parameter values for the following

    Parameter Comment
    User Storage Account Name Name of the storage account where the VHD image is stored
    User Storage Container Name Most likely the default vhds
    Dns Name For Public IP Provide a DNS name for the public IP; must be lowercase
    Admin User Name Set a username the administrator account for the new VM
    Admin Password Set an administrator password for the new VM
    OS Type Leave as Linux
    VM Size Size of the virtual machine instance (defaults to Standard_B1s)
    VM Name Provide a name for the VM resource
    VHD URL URL of the VHD Image we created above. This can be found on the blob details page. Navigate to: storage account -> containers -> vhds -> VHD image blob name

    It is a good idea to create a new resource group for the test VM. However the deployment will fail if the target storage account for the new VHD is not the same account hosting the source VHD image. Either:

    • use the account that was created in the previous steps of the lab (resulting in the new VM and its VHD being in different resource groups) or
    • create a resource group and storage account and copy the VHD image to the new storage account before creating the VM in the same resource group

    The first approach is simpler and adequate for the purposes of a test. Once finished testing you can delete the resource group and the new (specialised) VHD from the original storage account. Be careful not to delete the generalised VHD image.

  6. To finalise the test:

    1. confirm that browsing to the IP address of the new VM displays the NGINX welcome page
    2. ssh into the new VM and confirm the presence of a /tmp/users.txt file with a creation time matching the last reboot

Run validations on the virtual machine

  1. Prior to submitting for certification, you should run a set of validation tests against a VM created from the VHD image. We can use the VM we created in the previous step.

  2. There are two ways to do this:

    1. Use the Certification Test Tool for Azure Certified

      This is a Windows application that walks through the process of connecting to the VM, running a series of tests and producing a report. You can create a small Windows VM in Azure and install it on that to test. We will use this approach for the lab.

    2. Use the Self-Test API

      This is an API hosted in Azure. You send a POST request to the API with details of the machine to test and it returns a test report. You need to create an AAD app registration to authenticate with the API. You can find more details here. There is an excellent walkthrough video here which also bridges some of the gaps in the documentation.

  3. Install the Certification Test Tool for Azure Certified on a Windows Machine. Download Link

  4. Run the Certification Test Tool and enter the required information (test name, platform, auth type, DNS name for the VM to be tested etc)

  5. On completion you will be presented with a set of test results. Review the results and ensure you take any necessary action before submitting a final image for certification.

    The VM test tool results

  6. In this lab we will be submitting a VM offer to the marketplace but only to the preview stage for testing purposes. We will not submit for final certification.

    While attention should be paid to the results of the report, it is not necessarily required to fix every issue for the purposes of completing the lab.

Generate a SAS URL to the VHD Image

The final thing to do is generate a SAS URL pointing to the generalised VHD image. We need to supply this as part of the technical configuration when we create our VM offer.

  1. We need to collect two parameters before we can generate the SAS signature. For convenience we’ll store them in environment variables.

    Parameter Comment
    <connection-string> The connection string for the storage account where the VHD generalised image is stored. Navigate to the storage account and select Access Keys under Settings
    <vhd-name> Name of the VHD image itself. Navigate to the storage account then to Containers then vhds and copy the name of the generalised VHD blob
  2. Set environment variables using Azure CLI

    Modify the command below by substituting the parameter values you gathered above and submit via the Azure CLI:

    CONNSTR='<connection-string>'
    VHDNAME='<vhd-name>'
    
  3. Firstly we need the blob endpoint URL:

    BASEURL=$(az storage blob url \
       --container-name 'vhds' \
       --name $VHDNAME \
       --connection-string $CONNSTR \
       --output 'tsv')
    
  4. Then we need the SAS signature at the container level:

    START=$(date --date="yesterday" '+%Y-%m-%dT%H:%MZ')
    EXPIRY=$(date --date="1 month" '+%Y-%m-%dT%H:%MZ')
    
    SASSIG=$(az storage container generate-sas \
       --connection-string $CONNSTR \
       --name 'vhds' \
       --permissions 'rl' \
       --start $START \
       --expiry $EXPIRY \
       --output 'tsv')
    
  5. Finally, combine the two results to get the full SAS URL:

    echo ${BASEURL}?${SASSIG}
    

    Example output

    https://vhdstorage732682030108cd.blob.core.windows.net/vhds/osdisk_7326820301.vhd?st=2020-12-22T15%3A29Z&se=2021-01-23T15%3A29Z&sp=rl&sv=2018-11-09&sr=c&sig=V0OzA60J1JsknDnE7u6XtU0nk/icOV%2BmGqNigFmo9CI%3D
    

    Copy the output somewhere safe. You will need the SAS URL to publish the offer.

Next

You have the option to choose the appropriate offer type

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