Azure Virtual Machine Scale Sets (VMSS) Instance discovery

  • Release version: Zurich
  • Updated July 31, 2025
  • 4 minutes to read
    • Summarize
    Summarized using AI
    This content was generated using new OpenAI-powered functionality. Results are provided on an as is basis and are not guaranteed to be accurate or complete.

    Summary of Azure Virtual Machine Scale Sets (VMSS) Instance Discovery

    This document explains how ServiceNow's Discovery and Service Mapping Patterns application identifies and collects data on Azure Virtual Machine Scale Sets (VMSS) and their instances. VMSS allows automatic scaling of load-balanced virtual machines based on demand or schedules. The discovery uses two key patterns:Azure - VM Scale Set (LP)andAzure VM Instance - Uniform Scale Set. These patterns support both Uniform and Flexible orchestration modes of VMSS.

    Show full answer Show less

    ServiceNow customers may need to update the Discovery and Service Mapping Patterns app to the latest version from the ServiceNow Store to access full VMSS discovery capabilities.

    Key Features

    • Discovery Patterns: The Azure - VM Scale Set (LP) pattern discovers scale sets, while the Azure VM Instance - Uniform Scale Set pattern discovers individual VM instances within those sets.
    • Orchestration Modes: Supports both Flexible orchestration (multiple VM types with high availability) and Uniform orchestration (identical VM instances optimized for stateless workloads).
    • CMDB Population: Discovers and populates configuration items (CIs) such as Instance Scale Sets, Virtual Machine Instances, Storage Volumes, Network Interfaces, VNIC Endpoints, OS Images, and Hardware Types into the CMDB.
    • Tag Collection: Collects Azure resource tags and stores them in the Key Value [cmdbkeyvalue] table for enhanced metadata management.
    • CI Relationships: Automatically establishes critical relationships among CIs, including resource group containment, hosting, management, provisioning, and endpoint associations, ensuring a complete and accurate service model.
    • Server CI Creation without IP Discovery: Starting from version 1.31.0, Server CIs can be created during cloud discovery without running IP-based discovery, streamlining the process.

    Key Outcomes

    • Comprehensive Visibility: Enables customers to gain detailed visibility into Azure VM Scale Sets and their instances, including states, hardware, storage, and network configurations.
    • Accurate CMDB Data: Populates relevant CI tables with essential attributes such as install status, operational status, provisioning state, and unique Azure Object IDs, supporting effective IT operations and asset management.
    • Improved Service Mapping: By capturing precise CI relationships, customers can achieve more accurate service maps and dependency views for Azure environments.
    • Efficient Scaling Management: Supports discovery of both Uniform and Flexible VMSS orchestrations, helping customers monitor scaling behaviors and VM health efficiently.
    • Optimized Resource Categorization: Offers options to store OS images and hardware types in specialized cloud-specific classes to avoid excessive record counts and improve CMDB performance.

    Practical Considerations

    • Ensure prerequisites for Microsoft Azure discovery are met as per Microsoft Azure Cloud discovery guidelines.
    • Update to the latest Discovery and Service Mapping Patterns application version from the ServiceNow Store to access full VMSS discovery features.
    • Consider enabling Cloud OS Image and Cloud Hardware Type class extensions to better manage large numbers of discovered images and hardware types.

    The Discovery and Service Mapping Patterns application uses the Azure - VM Scale Set (LP) and the Azure VM Instance - Uniform Scale Set patterns to find Azure Virtual Machine Scale Sets (VMSS). Discovering some of these resources may require updating to the latest version of the Discovery and Service Mapping Patterns application from the ServiceNow Store.

    VMSS let you create and manage a group of load balanced virtual machines (VMs). The number of VM instances can automatically increase or decrease in response to demand or a defined schedule. There Uniform Orchestration modes Flexible and achieve.
    • VMSS with Flexible Orchestration achieves high availability at scale with identical or multiple virtual machine types. With Flexible orchestration, Azure provides a unified experience across the Azure VM ecosystem.
    • VMSS with Uniform Orchestration optimized for large-scale stateless workloads with identical instances. VMSS with Uniform orchestration use a virtual machine profile or template to scale up to desired capacity. While there is some ability to manage or customize individual virtual machine instances, Uniform uses identical VM instances.

    Request apps on the Store

    Visit the ServiceNow Store website to view all the available apps and for information about submitting requests to the store. For cumulative release notes information for all released apps, see the ServiceNow Store version history release notes.

    To learn about VMSS and their versions that you can discover, refer to Detailed information on products discovered by ITOM Visibility.

    Prerequisites

    Data collected by Discovery during horizontal discovery

    Discovery populates the data in the CMDB when running the Azure - VM Scale Set (LP) Pattern.

    Table 1. Instance Scale Set [cmdb_ci_instance_scale_set]
    Field Description
    Install Status [install_status] Install status of the instance scale set. Default value is Installed.
    State [state] Provisioning state of the instance scale set. Possible values are Available or Terminated.
    Object ID [object_id] A unique identifier for the instance scale set.
    Name [name] Name of the instance scale set.

    Discovery populates the data in the CMDB when running the Azure VM Instance - Uniform Scale Set pattern.

    Table 2. Virtual Machine Instance [cmdb_ci_vm_instance]
    Field Description
    Network adapters [nics] Number of Network Interface Cards (NICs) attached to the virtual machine (VM) instance.
    State [state] Current state of the instance. For example: On, Off, or Terminated.
    Install Status [install_status] Install status of the instance. Default value is Installed.
    Operational status [operational_status] Operational status of the instance. Default value is Operational.
    Disks [disks] Number of disks attached to the instance.
    Disks size (GB) [disk_size] Total storage capacity of all disks attached to the VM, in gigabytes (GB).
    Table 3. Storage Volume [cmdb_ci_storage_volume]
    Field Description
    Name [name] Name or ID for the storage volume.
    Object ID [object_id] A unique identifier, allocated by Microsoft Azure for this resource.
    Install Status [install_status] Install status of the storage volume. Default value is Installed.
    Operational status [operational_status] Operational status of the storage volume. Default value is Operational.
    Table 4. Cloud Mgmt Network Interface [cmdb_ci_nic]
    Field Description
    Name [name] Name or ID for the network interface.
    Object ID [object_id] A unique identifier, allocated by Microsoft Azure for this resource.
    Install Status [install_status] Install status of the network interface. Default status is Installed.
    Operational status [operational_status] Operational status of the network interface. Default status is Operational.
    Table 5. VNIC Endpoint [cmdb_ci_endpoint_vnic]
    Field Description
    Name [name] Name or ID for the endpoint.
    Object ID [object_id] A unique identifier, allocated by Microsoft Azure for this resource.
    Table 6. Image [cmdb_ci_os_template]
    Field Description
    Name [name] Name or ID for the image.
    Object ID [object_id] A unique identifier, allocated by Microsoft Azure for this resource.
    Install Status [install_status] Install status of the image. Default value is Installed.
    Operational status [operational_status] Operational status of the image. Default value is operational.
    Note:
    When using the Image [cmdb_ci_os_template] table to store Cloud OS images, you may notice an unusually large number of records. To avoid this issue, you can store the discovered OS images in the Cloud Image [cmdb_ci_cloud_os_image] table. For more information, see Enable Cloud OS Image discovery.
    Table 7. Hardware Type [cmdb_ci_compute_template]
    Field Description
    Name [name] Name of the hardware type.
    Note:
    When using the Hardware Type [cmdb_ci_compute_template] table to store the hardware types, you may notice an unusually large number of records. To avoid this issue, you can store the discovered hardware types in the Cloud Hardware Type [cmdb_ci_cloud_hardware_type] table. For more information, see Enable the Cloud Hardware Type class extension.

    CI relationships

    Discovery creates these relationships to support the VMSS discovery, when running the Azure - VM Scale Set (LP) pattern.

    CI Relationship CI
    Resource Group [cmdb_ci_resource_group] Contains::Contained by Instance Scale Set [cmdb_ci_instance_scale_set]
    Instance Scale Set [cmdb_ci_instance_scale_set] Hosted on::Hosts Azure Datacenter [cmdb_ci_azure_datacenter]
    Instance Scale Set [cmdb_ci_instance_scale_set] Consumes::Consumed by Load Balancer Pool [cmdb_ci_lb_pool]

    Discovery creates these relationships to support the VMSS discovery, when running the when running the Azure - VM Scale Set (LP) pattern.

    CI Relationship CI
    Virtual Machine Instance [cmdb_ci_vm_instance] Managed by::Manages Instance Scale Set [cmdb_ci_instance_scale_set]
    Storage Volume [cmdb_ci_storage_volume] Hosted on::Hosts Azure Datacenter [cmdb_ci_azure_datacenter]
    Block Endpoint [cmdb_ci_endpoint_block] Implement End Point To::Implement End Point From Storage Volume [cmdb_ci_storage_volume]
    Virtual Machine Instance [cmdb_ci_vm_instance] Use End Point To::Use End Point From Block Endpoint [cmdb_ci_endpoint_block]
    Virtual Machine Instance [cmdb_ci_vm_instance] Hosted on::Hosts Azure Datacenter [cmdb_ci_azure_datacenter]
    Hardware Type [cmdb_ci_compute_template] Hosted on::Hosts Azure Datacenter [cmdb_ci_azure_datacenter]
    Virtual Machine Instance [cmdb_ci_vm_instance] Provisioned From::Provisioned Hardware Type [cmdb_ci_compute_template]
    Virtual Machine Instance [cmdb_ci_vm_instance] Provisioned From::Provisioned Cloud Hardware Type [cmdb_ci_cloud_hardware_type]
    Cloud Mgmt Network Interface [cmdb_ci_nic] Hosted on::Hosts Azure Datacenter [cmdb_ci_azure_datacenter]
    Virtual Machine Instance [cmdb_ci_vm_instance] Implement End Point To::Implement End Point From Cloud Mgmt Network Interface [cmdb_ci_nic]
    Virtual Machine Instance [cmdb_ci_vm_instance] Use End Point To::Use End Point From VNIC Endpoint [cmdb_ci_endpoint_vnic]
    Virtual Machine Instance [cmdb_ci_vm_instance] Provisioned From::Provisioned Image [cmdb_ci_os_template]
    Image [cmdb_ci_os_template] Hosted on::Hosts Azure Datacenter [cmdb_ci_azure_datacenter]

    Tags discovery

    Both the Azure - VM Scale Set (LP) and the Azure VM Instance - Uniform Scale Set patterns collect tags and populate them in the Key Value [cmdb_key_value] table.
    Table 8. Key Value [cmdb_key_value]
    Field Description
    Key [key] Tag name.
    Value [value] Tag value.