--- sourceDocument: Yokohama IT Operations Management sourceDocumentLink: https://www.servicenow.com/docs/r/yokohama/it-operations-management Release : - yokohama ft:locale : - en-US ft:publication_title : - Yokohama IT Operations Management ft:clusterId : - itom bundleId : - itom workflow : - Technology --- # Discovery probes and sensors # Discovery probes and sensors {#ariaid-title1} Release version: Yokohama Updated January 30, 2025 ![](https://www.servicenow.com/docs/portal-asset/ico-clock) 2 minutes to read Summarize ![AI sparkle icon](https://servicenow.com/docs/portal-asset/ai-sparkle-icon) Summarized using AI This content was generated using new OpenAI-powered functionality. Results are provided on an as is basis and are not guaranteed to be accurate or complete. ## Summary of Discovery probes and sensors Discovery probes and sensors are key components in ServiceNow Discovery that collect and process data to update the Configuration Management Database (CMDB). While newer releases increasingly use patterns for discovery tasks, probes and sensors remain crucial for customers not yet using patterns or maintaining customized probes. Probes collect data from devices, and sensors process this data to update the CMDB accurately. Show full answer Show less ## How Probes and Sensors Work Discovery operates in multiple phases: scanning, classification, identification, and exploration. Probes and sensors are essential during the scanning and classification phases and may still be used alongside patterns in later phases. The MID Server monitors the ECC queue for discovery tasks, runs probes to gather device information, and returns results to the ECC queue. Sensors then process this data and update the CMDB accordingly. Probes may include post-processing scripts executed on the MID Server before sending data to sensors. Multi-probes combine several probes into one, with multi-sensors handling the processing of their combined data through individual and main scripts. ## Probe Types * Windows computers and servers: Remote WMI queries, shell commands * UNIX and Linux servers: Shell commands via SSH (Bourne-compatible) * Storage devices: CIM/WBEM queries * Printers and network gear: SNMP queries * Web servers: HTTP header examination * Uninterruptible Power Supplies (UPS): SNMP queries ## Management and Customization ServiceNow provides a wide variety of pre-built probes and sensors, which typically require minimal modification. However, customers may need to adjust parameters or update customized probes and sensors after upgrading their instance to ensure compatibility with the latest versions. Multiprobes allow multiple queries to be executed efficiently under a single authentication. Additionally, custom probes can be created, such as one that reads data from a text file on a Windows computer to populate a CI in the CMDB, enabling flexibility to meet unique discovery requirements. Discovery probes and sensors perform data collection and update the Configuration Management Database (CMDB). With each release, patterns are replacing many probes and sensors for Discovery. Consider creating new patterns or editing existing ones if you want to customize what Discovery can find. The information on probes and sensors is intended for customers who are not using patterns yet and for customers who already have customized probes that are retained upon upgrade. See [Patterns and horizontal discovery](https://www.servicenow.com/docs/F1AaGd2A7GKs7d9ZAQQp5w#c-UsingPatternsForHorizontalDiscovery "A pattern is a series of operations that tell Discovery which CIs to find on your network, what credentials to use, and what tables to populate in the CMDB.") for more information on patterns. Note: For information on Probe to Pattern migration see the knowledge article [KB0694477](https://support.servicenow.com/kb_view.do?sysparm_article=KB0694477). ## Discovery phases {#c_DiscoveryProbesAndSensors__section_ug3_fv2_dcb} Discovery always uses probes and sensors during the first two phases of discovery: scanning and classification. For the last two phases, identification and exploration, Discovery can use probes and sensors or patterns. This topic refers to probes and sensors only. See [Exploring Discovery](https://www.servicenow.com/docs/0y16n1wev3IjSWn6FtCyjQ "Discovery finds computers, servers, printers, a variety of IP-enabled devices, and the applications that run on them. It can then update the CIs in your CMDB with the data it collects.") for an explanation of these phases. See [Patterns and horizontal discovery](https://www.servicenow.com/docs/F1AaGd2A7GKs7d9ZAQQp5w#c-UsingPatternsForHorizontalDiscovery "A pattern is a series of operations that tell Discovery which CIs to find on your network, what credentials to use, and what tables to populate in the CMDB.") for more information on patterns. ## Probes, sensors, and the ECC queue {#c_DiscoveryProbesAndSensors__section_zh4_dv2_dcb} The probe collects the information and the sensor processes it. Both get their instructions from the ECC queue. There is a worker job on the MID Server that monitors the queue for work. The monitor checks for any entries where the Queue is output and the State is ready. The MID Server then processes all the output ECC messages, runs the necessary probes, and returns the probes results to the ECC queue. These results are put in the ECC queue as input entries.Figure 1. ECC queue input After an entry is inserted in the ECC Queue table, a business rule fires (on insert) that takes that information and runs it through a sensor processor. The sensor processor's job is to take the input data, find any sensors interested in that data, and pass it along to be processed. Those sensors ultimately update the CMDB. ## How probes and sensors work together The MID Server launches probes to collect information about a device. The probe sends back information to the sensor to be processed. If the probe has a post-processing script defined, the post-processing script does some data processing on the MID Server before data is sent back to the sensor on the ServiceNow instance. Otherwise the probes sends back all the data collected and the sensor performs this data processing. In both cases, the sensor updates the CMDB. A multi-probe is a probe that contains probes. A multi-sensor processes the data from a multi-probe. To process the data from the multi-probe, the multi-sensor contains individual scripts to process the data returned by each probe contained in the Multiprobe, as well as a main multi-sensor script. The individual scripts pass their processed data to the main multi-sensor script. ## Probe types {#c_DiscoveryProbesAndSensors__table_ixz_r1l_z4__entry__2} | Device | Probe Type | |-|-| | Windows computers and servers | Remote WMI queries, shell commands | | UNIX and Linux servers | Shell command (via SSH protocol, version 2). Discovery supports any Bourne-compatible shell. | | Storage | CIM/WBEM queries | | Printers | SNMP queries | | Network gear (switches, routers, etc.) | SNMP queries | | Web servers | HTTP header examination | | Uninterruptible Power Supplies (UPS) | SNMP queries | [ ] {#c_DiscoveryProbesAndSensors__table_ixz_r1l_z4} * **[List of Discovery probes](https://www.servicenow.com/docs/F4fPHL_pRcSyOUcSLoqUPA)** A wide variety of probes exist for the Discovery application to detect elements on your network. * **[Discovery sensors](https://www.servicenow.com/docs/wWNT7bd0pTJjUibDqy3T5w#r_Sensors)** Every probe in Discovery must have a corresponding sensor to process the data returned. * **[Discovery probe management](https://www.servicenow.com/docs/K80y4uGKzeYB9BNTLkXs6Q)** Several discovery probes and their associated sensors are included with Discovery. You rarely need to modify probes or sensors. But you might need to set parameters to control the behavior of a particular probe or align versions of customized probes. * **[Align versions of customized probes and sensors](https://www.servicenow.com/docs/RoFIyn73nJB8CElKjpLU0Q)** If you customized a probe or sensor and upgraded to a new instance version, realign the customized probe and sensor to the most current version. * **[Discovery multiprobes and multisensors](https://www.servicenow.com/docs/d~uAmStwz2Y3bx50t2CPpA#r_MultiprobesIncludedWithDiscovery)** Multiprobes contain one or more simple probes configured to extract specific information from manageable devices by executing multiple queries with a single authentication. * **[Custom Discovery probe to populate a CI from a text file](https://www.servicenow.com/docs/XDvLXHzDHOUvYO0YRFlKoA)** This custom Discovery probe reads a text file from a Windows computer and populates a configuration item (CI) in the CMDB with the values from the file.