ServiceNow Discovery is a process that automatically identifies the devices on your network, and then updates the Configuration Management Database (CMDB) with the information it finds. It uses a series of probes and sensors to detect devices on your network, classify them, and then update the CMDB with the details it finds.
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- The instructions are placed in the ECC Queue as output probes.
- Mid servers monitor the ECC Queue for jobs to be executed.
- Mid servers interrogate the target devices for the information according to the probe instructions.
- Mid servers report target responses as inbound probes back to ECC queue in the form of XML payload.
- XML payload is processed by the discovery pattern and the CMDB is updated accordingly.
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- Discovery starts either on a schedule or manually via Quick Discovery and it looks at specific IP ranges.
- A job is created in the ECC queue, and a mid-server picks it up.
- The mid-server scans the IP ranges for open ports like WMI, SNMP, SSH, HTTP, etc. This helps identify the type of devices.
- Based on the scan results, the mid-server classifies the device type.
- The device type is compared to a list in the CMDB to further classify the device, like a Windows 2019 server.
- More probes and patterns are used to identify and explore the device in detail, collecting data like serial numbers, IP and MAC addresses, CPU, OS, installed software, etc.
- This data is processed to check if the device already exists in the CMDB. If it does, the record is updated. If not, a new record is created.
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The Discovery Phases are as follows:
- Scanning Phase: This phase begins with a port probe scanning the predefined IP ranges for a list of open ports, such as WMI, SNMP, SSH, HTTP, and more. Identifying open ports helps to classify the type of devices that are being discovered.
- Classification Phase: Based on the return results, the classification phase determines exactly what type of device has responded to the open port identified during the scanning phase. The results are compared to a list of CI classifications in the CMDB to further determine the device.
- Identification Phase: Once discovery has identified that device as a Windows server, then it can see if that device already exists in the CMDB through the identification phase. Once discovery determines if the device exists or not, a record will either be created or an existing record will be updated.
- Exploration Phase: Next, discovery will go through the exploration phase to gather further details about that device. These probes can be viewed in the Status record on the ECC queue tab, and there you can see how many of the probes were sent out, and how many were returned.
In essence, Discovery is a process that identifies, classifies, and updates device information in the CMDB. It uses a mid-server to scan and collect data, which is then processed and stored in the CMDB. It helps keep the CMDB up-to-date and accurate.
