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Design your configuration plan

Start small and grow gradually as you design the CMDB with configuration items.

Take the time to familiarize yourself with the CMDB, its features and functions. Develop an understanding of design options for the CMDB and the broader ecosystem of federated systems and data feeds.

Your CMDB is populated with configuration items (CIs), which must be classified for you to have a properly managed CMDB. When you start this process, start small and grow gradually. Also make sure that there are no duplicate CIs.

Decide which CI classes and attributes you need to support the use cases you identified in Stage 1. Most organizations start simple and make incremental improvements as they gain experience. From this, you should be able to identify the types of CI classes you will need to manage. You will need to make sure these CI classes are at the appropriate level – as in what level of definition is meaningful to the use cases you have identified earlier. As a general recommendation, start with using the CI classes defined out‑of‑the‑box for CIs that can be discovered with ServiceNow. These CI classes have been vetted by thousands of our customers and should contain all the attributes your efforts will need.

For example, you might start with a hardware CI class, so you assign some simple attributes: CPU, memory, etc. As you build your CMDB, you’ll map computers, servers, routers, switches, and so on. Each of these CIs will have attributes and each one of them will have relationships and dependencies. Warning: Your CI tables can get out of control quickly if you don’t simplify them! Keep their names intuitive so they are easy to identify and remember.

One large insurance customer warns that it’s easy to add data to the CMDB but harder to maintain the model.

For CI classes that are not discoverable, you might need to extend an out‑of‑the‑box class. Figure 3 depicts how the CMDB leverages object‑oriented inheritance in the creation of all CI classes.

Definition

Configuration Item

A CI is one of the most important components of your CMDB. It’s simply an application, infrastructure, or service component you’re managing. It can be a physical server, an app running on a virtual server, or a business service.

Figure 3: Example of a table extension model that grows with complexity

Our customers start by classifying these CIs:

  • Windows server
  • Linux server
  • Firewall
  • Load balancer
  • Database
  • Network Router
  • Network Switch
  • Storage
  • Application Server

If you are using ServiceNow Discovery, it will find all the network infrastructure, applications, and services and populate into the CMDB.

Dependency maps let you see where your CIs support a critical service. For example, the loss of disk drives may take a database instance down, which affects the requisition service the HR department uses to order equipment for new employees. If you are using ServiceNow Discovery or Service Mapping products, the dependencies between discoverable CIs will be built for you automatically as the CMDB is updated by discovery updates, see figure 4.

Figure 4: ServiceNow CMDB dependency map

For the logical “business layers” that are not discoverable, you need to define the relationships between discoverable and nondiscoverable CIs in your business model.

For each CI class, you will need to make sure the CMDB is configured properly.  Use CI Class Manager to configure the rules for each CI class to ensure you have all the necessary information about your CIs at one place. The CMDB stores all the information you want to capture and manage on an ongoing basis and can record relationships between attributes in the CMDB.

Figure 5: ServiceNow CI Class Manager

To manage changes to CMDB, we recommend setting up Configuration Control that eliminates risks of unnecessary tweaks to the CIs. Based on customer implementations, we suggest that you proactively manage CIs and their dependencies when they’re added, deleted, and modified. When a business process like incident management requests a change to the CIs, you should:

 

  1. Allow change requests via Change Management. You can easily do this using the 'Propose Change' feature if you have ServiceNow Change Management enabled.
  2. Assign proper privileges to the authorized users to make changes; normally it’s a member of your team such as a CM Analyst.
  3. Validate CI attributes against agreed criteria in your configuration management plan.
  4. Update the CMDB with the necessary changes and communicate to stakeholders.
Expert Tip

Expert Tip

Set a data dictionary to organize CI Class Manager. The data dictionary will help you define what each field in the CMDB is used for (and ensure that your fields align to your configuration management goals).

Explore additional phases

Plan

You want to be sure everything is in place for a smooth, successful deployment.

Deploy

You want to be sure you’re following best practices during implementation.

Optimize

You’re up and running and want to get the most from your investment.

Extend

You’re ready to extend ServiceNow into other areas of your enterprise.