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32 Configuration Management

Lecture 4: Configuration Management

I. Introduction

  • Definition (from Wikipedia): Configuration Management (CM) is a process that tracks all individual configuration items (CIs) within an IT system. This system can range from a single server to an entire IT department. The key is tracking and managing the components.

II. Core Concepts: Configuration Items (CIs) and the CMDB

  • Configuration Item (CI): Any component that needs to be managed to deliver an IT service. This is the fundamental building block of CM.

    • Examples: Servers, network switches, routers, software, desktops, laptops, virtual machines (VMs). Can be tangible (hardware) or intangible (software, services).
    • Scale: A mature CMDB in a large organization can contain millions of CIs.
    • CI Class: A category or type of CI. Think of it like a folder structure.
      • Example: "Servers" is a CI class.
      • Child Classes: "Windows Servers" and "Linux Servers" could be child classes of "Servers". This creates a hierarchy.
    • CI Records: CIs are stored as records in the CMDB_CI table (or its many extended tables) within ServiceNow. Each CI class has its own table.
    • Relationships: The configuration item's relationships.

  • Configuration Management Database (CMDB): The database that stores all the CIs and their relationships. It's the heart of configuration management.

  • CI Relationships: CIs are connected to each other through defined relationships. These connections are crucial for understanding dependencies.

    • Example: A server supports an email service. "Supports" is the relationship.
    • Directionality: Relationships have direction:
      • Upstream: Towards applications or services (e.g., "supports").
      • Downstream: Towards hardware or infrastructure (e.g., "supported by").
    • Complexity: CIs can have few or many relationships, depending on their role.

III. Purpose and Benefits of a CMDB

  • Dependency Views/Maps: Visual representations of CI relationships. These are extremely powerful for understanding how different parts of the IT infrastructure are connected.
  • Troubleshooting: Helps identify the root cause of incidents and problems more quickly by showing dependencies.
  • Change Management: Reduces conflicts during changes by showing the potential impact of changes on other systems.
  • Granularity: A CMDB can be as detailed as an organization needs. It might start with only critical systems and expand over time.
  • Resource Investment: Building and maintaining a CMDB requires resources (people, tools, processes).
  • Data Population: CIs can be added to the CMDB through:
    • Manual Import: Importing data from spreadsheets.
    • Automated Tools: Using discovery tools like ServiceNow Discovery or Microsoft SCCM. These tools automatically find and populate CIs.
  • Data Freshness: A CMDB must be kept up-to-date to be valuable. Stale data leads to inaccurate information. Processes for creating and updating CIs are essential.

IV. Configuration Management in ServiceNow (Practical Demonstration)

  • Configuration Application: The main area within ServiceNow for managing the CMDB. It has a lot of modules because each CI class often has its own module.

  • Exploring CI Records:

    • Application Servers (cmdb_ci_app_server): Shows CIs representing application servers (e.g., a Java application server). The form view shows details like name, category, version, managed by, support group, and related items (relationships).
    • Servers (cmdb_ci_server): Shows CIs representing physical servers. The form view includes hardware-specific details like asset tag, manufacturer, OS, RAM, CPU, etc.

  • Key ServiceNow Modules:

    • CI Class Manager: A central place to view the hierarchy of all CI classes and their configurations (fields, relationships, etc.). Provides a "single pane of glass."
    • CMDB Groups: Allows creating groups of CIs (e.g., a "Servers Admin Group").
    • CMDB Query Builder: A graphical tool for building queries to find specific CIs based on criteria.
    • Business Services: Services essential for business operations (e.g., email, trading software). These are high-level CIs. The dependency view is particularly important at this level.
    • Dependency View Button: Loads the dependency map, a visual representation of the relationships between a business service and other CIs. Shows upstream (supported services) and downstream (supporting infrastructure) dependencies.
    • Mass Storage Devices: Example of a low-level CI (infrastructure) that supports many other CIs. The dependency view shows all the systems that rely on this storage.
    • CMDB Dashboards: Provide visual overviews of the CMDB (charts, graphs, statistics).
    • CMDB Classifications: The bulk of the Configuration application, listing modules for various CI classes (Application Servers, Servers, Clusters, Databases, etc.). Each has an "All" module to list all records of that type.
    • Relationships Section: Crucially important for defining the types of relationships between CIs.
      • CI Relationship Types: Predefined relationships (e.g., "depends on," "used by," "contains," "runs on"). These define the type of connection between CIs.
      • CI User Relationship Types: Relationships between CIs and users.
      • CI Group Relationships: Relationships between CIs and groups.
      • Suggested Relationships: Pre-configured, based on ServiceNow.
    • CI Identifiers: Unique identifiers for different types of CIs. Each identifier has its own table.

  • Creating Relationships Manually:

    • Navigate to a CI record (e.g., an application server).
    • Click the "+" button under "Related Items" to add a relationship.
    • Use the Relationship Editor:
      • Shows existing relationships (parent/child).
      • Provides suggested relationship types (e.g., "depends on," "runs on").
      • Allows selecting another CI to create the relationship.
      • Displays the relationship in both directions (e.g., "A sends data to B" and "B receives data from A").
    • Save the relationship.
    • View the updated dependency map to see the new connection.

  • Automated Relationship Creation (ServiceNow Discovery): A more advanced topic. Discovery can automatically create relationships, which is essential for large CMDBs where manual creation is impractical.

V. Key Takeaways

  • Configuration Management is about tracking and managing IT components (CIs).
  • The CMDB is the central database for storing CIs and their relationships.
  • Relationships are crucial for understanding dependencies and the impact of changes.
  • ServiceNow provides tools for managing CIs, defining relationships, and visualizing dependencies.
  • Automated discovery is essential for large-scale CMDBs.
  • Keeping the CMDB up-to-date is critical for its effectiveness.

This detailed summary breaks down the lecture into its core components, making it easier to understand and use as study material. It emphasizes the key concepts, the practical aspects within ServiceNow, and the overall importance of configuration management.

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