🧩 ServiceNow Discovery: Using Patterns
In the previous article, we explored how to discover additional information about a Computer CI using the traditional Probes and Sensors method in ServiceNow. 🖥️
Now, it’s time to move to the next evolution of Discovery — using Patterns! 🚀
What Are Discovery Patterns?
Patterns, much like Probes and Sensors, are designed to collect data from a host, process it, and update the CMDB with meaningful configuration information.
However, Patterns differ in several key ways:
🧠 They are written in Neebula Discovery Language (NDL) — not JavaScript.
⚙️ They operate in the later stages of the Horizontal Discovery process.
🎯 They provide a visual and modular way to define Discovery logic using the Pattern Designer.
In short — while Probes and Sensors are script-driven 🧾, Patterns are flow-driven, making Discovery more intuitive, reusable, and maintainable.
🔍 How Patterns Differ from Probes & Sensors
Let’s make the difference crystal clear 👇
|
Aspect |
Probes & Sensors |
Patterns |
|
Language |
JavaScript |
Neebula Discovery Language (NDL) |
|
Execution Stage |
Early / Mid (Classification & Exploration) |
Later (Horizontal Discovery) |
|
Interface |
Code-based |
Visual Pattern Designer |
|
Purpose |
Collect and process data |
Collect, process, and relate CIs |
|
Flexibility |
Custom scripting |
Drag-and-drop logic blocks |
|
Debugging |
ECC Queue logs |
Built-in Pattern Debugger |
🧠 Why Use Patterns?
Patterns make Discovery smarter and simpler:
🔹 They provide a graphical interface to design and test Discovery logic.
🔹 They reduce script maintenance, since you can modify flow logic visually.
🔹 They are context-aware, automatically understanding which CI is being discovered.
🔹 They help build relationships between CIs, forming the foundation for Service Mapping.
🧪 Before You Start Building Patterns
Before you dive into writing your first Pattern, it’s important to know what you’re aiming to discover 🎯.
The type of device or application determines how you’ll communicate with it — whether via SSH, WMI, SNMP, HTTP, or database connections.
💬 In other words, you must understand the “language” your target system
⚙️ Discovery vs. Service Mapping — Know the Context
While Discovery Patterns focus on populating data into the CMDB,
Service Mapping Patterns are primarily designed to build relationships between CIs across layers of a business service. 🌐
The syntax and design logic are similar — but their goals differ:
- Discovery Patterns = populate and enrich CI data
- Service Mapping Patterns = define application dependencies
Navigate to Discovery Definition -> Windows and Open Windows record
🪟 As you can see, the Windows Classifier is configured to launch the Pattern named Windows - OS Desktop during the Discovery process.
🔍 In our earlier Discovery run, this same Pattern was automatically triggered during the Exploration phase, where it collected detailed configuration data about the Windows system.
📘 You can verify this by navigating to the Discovery Log tab — it shows exactly when and how the Windows - OS Desktop Pattern was executed.
📸 Refer to the screenshot below for a visual confirmation.
🧩 Before we begin designing the Pattern, let’s first create a new field to store additional data — for example, the IPv6 Address of the target machine 🌐.
You can choose to reuse the ‘Some Extra Info’ field that we created earlier during the Probe/Sensor demo, but it’s recommended to keep them separate to avoid any data conflicts between Pattern-based Discovery and Probe/Sensor-based Discovery ⚙️.
🛠️ In this example, I’ve created a new field on the Computer CI table named IPv6 Address (u_ipv6_address). This field will hold the IPv6 data collected by our Pattern during Discovery.
🚀 Now we’re going to populate this field using a Discovery Pattern instead of Probes and Sensors.
You can access the Pattern in two ways:
- 🧭 From the Windows Classifier record (if it’s already open), or
- 🧩 Navigate to Pattern Designer → Discovery Patterns, and locate the Windows OS – Desktop pattern.
Once you’ve opened the pattern, scroll down to the Extension Sections area.
Create a new section named Extra Windows Info, then click Save, and open this new extension section to begin adding your pattern logic. 💡
🖥️ Enter the host name or IP address of the target machine and click Connect.
Once the connection is established, the Debug indicator will turn green ✅ — confirming that you’re successfully connected to the host.
⚡ Note: If you’re connecting for the first time, it may take a little longer to establish the connection, as initial authentication and setup steps are performed.
🔗 Once the connection is established, the connected host will be displayed in the list below.
After verifying the connection, simply click Close to proceed. ✅
Create a Step called Get Windows Command Info.
Configure the details as shown below
⚙️ Click Run Command, and you’ll see the command output displayed in the Output panel 🖥️.
Next, use the Delimited Text Parsing technique along with the Include Lines field to extract the specific data you want — in this case, the IPv6 address 🌐.
📋 Then, in the Variables section, click Table and specify the following:
- Table Name: cmdb_ci_computer
- Field Name: u_ipv6_address
💡 This configuration tells the Pattern to extract the IPv6 address from the command output and populate it into the u_ipv6_address field of the Computer CI record in the CMDB.
Finally, click the Test button 🧪 — you should see the IPv6 Address value successfully set on the target CI.
🎯 Our job is now complete! When you re-run the Discovery, the Horizontal Discovery Probe will automatically trigger the Windows - OS Desktop pattern during the Exploration phase. 🧠
Within this pattern, the Extension Section we created will execute and populate the IPv6 Address field (u_ipv6_address) in the Computer CI record. 🌐
🪄 Once the Discovery process finishes, navigate to the Discovery Logs and open the entry for the Windows - OS Desktop pattern.
Here, you’ll be able to see your Extension Section in action — along with the IPv6 Address value successfully captured and set in the CMDB. ✅
📎 Click the “Here” link to view the log details and confirm that the value was updated correctly.
Go to updated CI and find that IP6 Address filed is populated successfully.
🎉 Congratulations! You’ve successfully performed Discovery using Patterns — a modern, visual, and efficient approach to identifying and enriching Configuration Items in the CMDB.
Unlike Probes and Sensors, which rely on JavaScript scripting, Patterns offer a graphical, modular, and declarative way to define Discovery logic.
They simplify maintenance, improve visibility, and allow you to extend existing Discovery flows without touching complex code. 🧩✨
By leveraging the Pattern Designer, you not only collected the IPv6 Address of the Windows machine but also experienced how Patterns seamlessly integrate with the Discovery lifecycle — from Classification → Exploration → CMDB Update. ⚙️
