Scheduled Update Deployments for Virtual Machine Scale Sets

Question

Pulumi · Accepted Answer

In order to create a scheduled update deployment for Virtual Machine Scale Sets (VMSS) on Azure, you would typically use a combination of resources to define your VMSS and then define a software update configuration that applies periodic updates to the VM instances within the set.

First, let's create the Virtual Machine Scale Set using the `azure_native.compute.VirtualMachineScaleSet` class. This resource allows you to define a scalable set of VMs that can be managed as a group for tasks such as load-balancing and scaling.

Once we have created the VMSS, we will proceed to create a software update configuration using the `azure_native.automation.SoftwareUpdateConfigurationByName` class. This configuration will specify the schedule, update settings for Windows and/or Linux machines, and any tasks to perform before or after the update process.

Here's how you can do this using Pulumi with Python:

```python
import pulumi
from pulumi_azure_native import compute as azure_compute
from pulumi_azure_native import resources
from pulumi_azure_native import automation

# Create an Azure Resource Group
resource_group = resources.ResourceGroup('resourceGroup')

# Specify the details of the Virtual Machine Scale Set
vmss = azure_compute.VirtualMachineScaleSet(
    "vmss",
    resource_group_name=resource_group.name,
    sku=azure_compute.SkuArgs(name="Standard_F2", tier="Standard", capacity=2),
    location=resource_group.location,
    # Define other necessary properties here...
)

# Now let's define the scheduled software update configuration.
# For demonstration, we will configure a weekly recurring update.
software_update_configuration = automation.SoftwareUpdateConfigurationByName(
    "softwareUpdateConfiguration",
    resource_group_name=resource_group.name,
    automation_account_name="your-automation-account-name",  # Replace with your automation account
    name="myWeeklyVmssUpdate",  # Name for the software update configuration
    update_configuration=automation.UpdateConfigurationArgs(
        # Define update settings for Windows or Linux as required
        operating_system="Windows",  # or "Linux"
        windows=automation.WindowsPropertiesArgs(
            excluded_kb_numbers=["KB123456"],
            included_update_classifications="Critical"
            # Additional properties...
        ),
        # Specify the VMSS targets for update deployment
        azure_virtual_machines=[vmss.id],
        # If you have Linux machines, configure Linux properties similarly
    ),
    schedule_info=automation.SchedulePropertiesArgs(
        frequency="Week",  # Could be "OneTime", "Day", "Week", "Month", etc.
        interval=1,  # Run every 1 week
        start_time="2023-01-01T17:00:00Z",  # Specify the start time in UTC
        time_zone="UTC",
        # Additional properties...
    ),
    tasks=automation.TaskPropertiesArgs(
        # Define any pre or post update tasks if necessary
        # Example: pre_task=automation.TaskPropertiesArgs(source="pre-update-script"),
    ),
    # Include further configuration details as necessary...
)

# Output the public IP of the load balancer used in VMSS, if applicable
pulumi.export('vmss_public_ip', vmss.public_ip_address)

# Output the name of the software update configuration
pulumi.export('softwareUpdateConfigurationName', software_update_configuration.name)
```

In the above program, we create a VMSS with a specific SKU and capacity. We then create a scheduled update deployment that is configured to run weekly. You can adjust the `update_configuration` and `schedule_info` parameters to meet your specific update and scheduling requirements.

The `azure_virtual_machines` parameter within `update_configuration` is important as it specifies the target for the deployment, which in this case is the `vmss.id` of the scale set we defined earlier.

The `schedule_info` parameter defines the schedule of the update deployment. The example above uses a weekly frequency, but you can adjust this to any of the supported frequencies such as "Day" or "Month".

The `tasks` parameter can include pre and post-tasks which can be PowerShell scripts, for example, that prepare your VMs for the update process or clean up tasks after updates are applied.

Please make sure you replace placeholders like `your-automation-account-name` with actual values from your Azure subscription.

This program is an illustrative example of how you might set up a VMSS with a scheduled update deployment using Pulumi and Azure. Depending on your specific use case, you might need to adjust the VMSS configuration or update configuration parameters.