Performing real-time updates to tags for cloud resources

  • Release version: Zurich
  • Updated July 31, 2025
  • 2 minutes to read
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    Summary of Performing real-time updates to tags for cloud resources

    This feature enables ServiceNow customers to perform real-time updates to tags on cloud resources by processing cloud events and applying tag policies dynamically. Instead of running audits across all Configuration Items (CIs), tag changes trigger targeted audits on specific impacted CIs, ensuring timely updates to the CMDB.

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    Prerequisites

    • The Cloud Events [sncmpcloudevents] table must have no records in the processed state to start.
    • CIs affected by tag changes must be identified through CAPI or Discovery and Service Mapping patterns.
    • At least one tag policy must be configured with the Run on cloud events checkbox selected to enable real-time auditing on tag change events.

    Setup Instructions

    Instructions vary by cloud provider:

    • Configure Amazon AWS Config service for automatic CMDB updates.
    • Configure Microsoft Azure Alert service for automatic CMDB updates.
    • Configure Google Cloud Operations Suite Logging service for automatic CMDB updates.

    Functionality

    When a tag change event occurs, the system identifies the impacted CI and runs the associated tag policy if applicable. This audit is event-driven and CI-specific, differing from traditional audits that cover all CIs under a policy. Tag change details and the type of change are logged in the Tag Change Log [snitomtagchangelog] table, which retains records for 90 days. This log includes tag additions or updates from both remediations and event triggers.

    Performance Optimization

    To maintain system performance under high event volumes or many tag policies, you can adjust the following system properties:

    • snitomtag.azurewindowsize: Defines the configurable time window (in minutes) for processing events.
    • snitomtag.maxauditlagratio: Controls the lag allowed between running audits before triggering new audits on ready records.
    • snitomtag.policybatchsize: Sets the batch size for running tag audits.
    • snitomtag.eventbatchsize: Determines the batch size of events processed at once.

    Adjusting these properties helps ensure real-time tag updates are processed efficiently without degrading overall system performance.

    You can set up cloud events processing and map a tag policy to update tags for cloud resources in real time.

    Prerequisites

    • Cloud events table [sn_cmp_cloud_events] table does not have any records in the processed state.
    • CIs impacted by tag change events are identified by either CAPI or Discovery and Service Mapping patterns.
    • Configured at least one tag policy.
    • Select the Run on cloud events check box in the tag policy you create.

    Instructions depend on the cloud provider

    See the following setup instructions for cloud event processing:

    Process cloud events related to changes in tags and execute tag audits on the events in real time.

    Unlike regular tag audits, where the audit is performed on all CIs in the CMDB that the tag policy applies to, tag events are processed per CI. Based on the prerequisites, tag event processing occurs on events that are identified with a tag change. The impacted CI is identified and, if the associated policy is applicable to the CI, the tag policy is run on the identified CI.

    If the Run on cloud events check box is selected during policy creation, the policy is selected to run an audit on tag change events. If the check box is cleared, the audit is not run on the CI even if there are tag change cloud events.

    View the change type that applies to the tag (the change that triggered the audit) in the Tag Change Log [sn_itom_tag_change_log] table. The records in the table are stored for 90 days by default. The change log records appear whether a remediation run or an event triggered the change on the CI. You can also view tags that were added or updated as part of the change.

    Optimizing performance

    High event inflow or a large number of tag policies can decrease performance. You can modify the following system properties to ensure acceptable performance:
    • [sn_itom_tag.azure_window_size] - This system property is configurable (in minutes).
    • [sn_itom_tag.max_audit_lag_ratio] - Specify the lag between tag audits that are already running, before the audit triggers on the records ready for audit.
    • [sn_itom_tag.policy_batch_size] - Batch size on which the tag audit is run.
    • [sn_itom_tag.event_batch_size] - Event batch size to be processed.