Preparing an application for config data upload

  • Release version: Xanadu
  • Updated August 1, 2024
  • 4 minutes to read
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    Summary of Preparing an application for config data upload

    This process enables ServiceNow customers to prepare an application in Configuration Data Management (CDM) to accept uploaded configuration data. An application in CDM represents the full set of configuration data for an application service, application model, or dynamic CI group in the CMDB. After uploading source configuration data, the application supports multiple deployables corresponding to different environments such as Development, Test, and Production.

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    Important: Starting with the Washington DC release, DevOps Config is being deprecated; it will no longer be installed on new instances but remains supported on existing ones.

    Preparing the Application

    • Create an application record via the Apps tab using a user with the CDM Admin role; this auto-generates a hierarchical folder structure to map your existing configuration data.
    • Create deployables for each environment type and multiple versions if needed.
    • Use the CDM code editor to create a changeset (a draft editable copy of the application) where you model your configuration data by creating nodes within the folders.
    • Upload your existing config data into the changeset using REST APIs or the CDM code editor.

    CDM supports uploading datasets such as component variables, components, collections, and deployables.

    Key Concepts

    • Components: Represent logical elements of an application or infrastructure service (e.g., micro-services, servers) and can contain variables with environment-specific values.
    • Collections: Define a release composition made up of components, possibly including override settings unique to that release version.
    • Deployables: Represent environment-specific config datasets (Development, Test, Production) that can be deployed in CI/CD pipelines. Deployables link collections and environment-specific overrides to services in the CMDB.

    After Upload and Commit

    • Update variable and override values in deployables to reflect environment-specific configurations efficiently.
    • Save and commit the changeset, triggering conflict checks, data persistence into the application data model, and snapshot generation per deployable.
    • Snapshots are immutable records of deployable configurations used for validation, export, and policy enforcement.
    • Manage your config data by mapping validation policies to deployables, validating snapshots, and exporting configuration as needed.

    Additional Notes

    • Starting in CDM version 4.2, node names can include any UTF-8 characters, including forward slashes.
    • Uploading XML or CSV files is supported with specific parsing rules for accurate data import.
    • Policy mapping to empty deployables is possible but uncommon.

    An application in CDM is the full collection of config data for an application service, application model, or dynamic CI group [infrastructure] in the CMDB. After you upload your source config data, the application can support all potential deployables that make up each version of the development, test, and production environments of the service.

    Important:
    Starting with the Washington DC release, DevOps Config is being prepared for future deprecation. It will be hidden and no longer installed on new instances but will continue to be supported. For details, see the Deprecation Process [KB0867184] article in the Now Support Knowledge Base.

    Overview: Preparing an application to accept uploaded config data

    You follow this general process to prepare an application to accept the upload of config data:
    1. On the Apps tab, you, a user with the CDM Admin [sn_cdm.cdm_admin] role, create an application record.

      The system generates an application that includes several standard folders in a hierarchical structure. You will map your existing config data into this data structure to enable the benefits that are described in CDM data model.

      Data structure for a new application. You will add your config data as nodes in the appropriate folder

      The application supports creation of multiple deployables. For example, you might create a deployable for each typical environment: Development, Test, and Production. You might also create multiple versions of each deployable for each environment type.

    2. Working in the CDM code editor, you now create a changeset — a draft copy of the application that you can edit.
    3. While working in the changeset, you create the following types of nodes in the appropriate folders. This process models the config data, that is, it prepares the application to map your source config data into the CDM data structure.
      Note:

      Starting with Configuration Data Management version 4.2, you can define a node using any UTF-8 character, including the forward slash (/).

    4. Now that the structure is in place, you use the REST APIs or the CDM code editing panel to upload your existing configuration data into the changeset. The process is described in Uploading your config data. For more information, see CdmApplicationsAPI, CdmChangesetsAPI, and CdmSnapshoAPI.
      Note:
      If you're uploading an XML or CSV file to import your existing config data into CDM, the CDM parser parses the data in a specific way. For more information, see Parsing of XML files in CDM and Parsing of CSV files in CDM.
      You can upload the following types of datasets: component variables, components, collections, and deployables.
      Components
      Components are the building blocks that typically represent the config data for a logical element of an application or a part of an infrastructure service. For example, a monolithic app, a micro-service, a physical server, or a Docker template.

      A component can contain variables that can take on different values in collections and deployables. More detailed instructions appear in Define or update a component.

      Collections

      A collection is the set of components that together define a release — You can think of a collection as a release composition.

      A collection can contain variable or override settings that are specific to the particular version. For example, the VM config data used in release-1 is different from the data used in release-2. release-1 might use the value 2Gb for the memory setting ("memory": "2Gb") and release-2 might specify a different value ("memory": "4Gb"). In addition, a collection might include config settings that do not appear in its components. You might think of such values as "overlays".

      Deployables

      A deployable is a config dataset (for a development, test, or production environment) that can be deployed into your CI/CD pipeline as a service. Each deployable in an application configures a service in the CMDB. For example, you might create three deployables, one for each environment type: Development, Test, and Production.

      A deployable is made up of the collection or set of collections that define the release for a particular environment. The combination of collections+environment link to an application service in the CMDB or an infrastructure service.

      A deployable can contain variable or override settings that are specific to the environment. For example, the database variable has one value in the development environment and a different value in the production environment. An override value in the production deployable might specify a required container parameter that is not needed in the development environment.

    5. After the data is uploaded, you return to CDM. You update variable and override values so that the relatively small set of components and collections can provide config data for all three deployable environments. For example, the Development deployable can use the same components and collections as the Test deployable. Development uses the default database variable value. Test, in contrast, uses a different value that is appropriate for the test environment.
    6. Now, save and commit the changeset. The system performs the following actions:
      • Determine whether there are conflicts with other earlier commits. If the system reports a conflict, you must resolve it and recommit or create a changeset and redo your changes. For more information on conflict resolution, see Conflicts between changeset commits.
      • Push all changes into the data model of the application (the config data is persisted).
      • Generate a snapshot of each deployable that is affected by the changes in the changeset. The system validates config data by executing specified policies against a snapshot. At the moment that the snapshot is created, the snapshot can be published and used to export the config data. Snapshots are permanent records that cannot be edited.
    The source config data is now held in CDM tables. You can now manage the data as needed: map policies to each deployable so that the snapshots can be validated, validate the data in a snapshot (apply the policies), export config data, and so on.
    Note:
    You can map policies to an empty deployable, but that is not a typical procedure.