Load balancer fields and probes

  • Release version: Xanadu
  • Updated August 1, 2024
  • 4 minutes to read
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    Summary of Load balancer fields and probes

    This documentation focuses on how ServiceNow Discovery collects and stores data about load balancers using probes and sensors. It details the specific fields populated in various load balancer-related Configuration Item (CI) tables during discovery. This information is relevant if you are using probes and sensors for load balancer discovery, not patterns such as those for F5 Big-IP, which have separate documentation.

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    By default, the system uses the discovered IP address (often the management IP) for the load balancer CI. Customers can configure Discovery to select the NIC IP address instead by adjusting IP address selection properties.

    Key Fields and Associated Probes

    Discovery populates multiple tables specific to different load balancer types and components, each with relevant fields gathered by dedicated probes:

    • Citrix Netscalers (cmdbcilbnetscaler): Includes serial number, asset tag, and model ID using SNMP Netscaler probes.
    • Cisco GSS (cmdbcilbciscogss): Populates serial number, model ID, IP address, and manufacturer via Cisco GSS probes.
    • Cisco CSS (cmdbcilbciscocss): Collects serial number, model ID, IP address, and manufacturer using SNMP Load Balancer probes.
    • F5 BIG-IP (cmdbcilbbigip): Fields include active modules, asset tag, model ID, failover mode and peer, and serial number, gathered primarily through SNMP and Cisco GSS probes; some fields require form customization to display.
    • General Load Balancer (cmdbcilb): Captures operational status and name using multiple probes including Apache, HAProxy, SNMP F5 BIG-IP, and Netscaler.
    • Load Balancer Application (cmdbcilbappl): Gathers configuration files, name, IP address, last discovery timestamp, and version from Apache, HAProxy, and Nginx probes.
    • Load Balancer Interface (cmdbcilbinterface): Tracks status, associated load balancer, and name with data from Apache, HAProxy, and SNMP probes; some fields may need form customization.
    • Load Balancer Pool (cmdbcilbpool): Includes load balancing method, associated load balancer, last discovery, and name, populated from Apache, HAProxy, SNMP, and Netscaler probes.
    • Load Balancer Pool Member (cmdbcilbpoolmember): Contains fully qualified domain name, IP address, load balancer association, last discovery, name, pool, and service port; data sourced from Apache, Nginx, HAProxy, SNMP, and Netscaler probes.
    • Load Balancer Service (cmdbcilbservice): Fields such as input URL, IP address, last port, load balancer, last discovery, and service port, gathered from Apache, Cisco GSS, HAProxy, Nginx, and SNMP probes.
    • Load Balancer VLAN (cmdbcilbvlan): Records load balancer reference, name, and tag using various probes including Apache, HAProxy, SNMP F5 BIG-IP, and Netscaler.

    Note that some fields are not visible on forms by default and require customization to display.

    Additional Load Balancer Data

    Discovery also collects data on Apache web server load balancing modules via SSH, such as modjk and modproxy. For comprehensive details on Apache web server discovery and related tables, fields, and probes, customers should consult the specific Apache web server discovery documentation.

    Practical Implications for ServiceNow Customers

    • Understanding these fields and their discovery sources helps ensure accurate and complete load balancer CI data in your CMDB.
    • Customization of forms may be necessary to make all discovered attributes visible for operational use and reporting.
    • Adjusting IP address selection properties allows you to tailor discovery to use management or NIC IP addresses, improving CI accuracy.
    • For specialized load balancers or discovery methods (like patterns for F5 Big-IP), refer to their dedicated topics to complement this probe-based approach.

    Discovery stores load balancer information in several tables.

    The information in this topic pertains to discovery with probes and sensors only. If you are using patterns, such as to discover F5 Big-IP load balancers, see the relevant topic for that type of load balancer.

    Note:
    By default, the system uses the discovered IP address of a load balancer for the CI record. This can be the management IP created for the device that is used in the Discovery schedule. For instructions on how to force Discovery to use the IP address of the load balancer's NIC rather than that of a management IP, see IP address selection properties.
    Table 1. Fields on the Citrix Netscalers [cmdb_ci_lb_netscaler] table
    Field label and name Probes that gather data
    Serial Number [serial_number] SNMP - Netscaler - Identity - Serial
    Asset tag [asset_tag] SNMP - Netscaler - Identity
    Model ID [model_id] SNMP - Netscaler - Identity
    Table 2. Fields on the Cisco GSS [cmdb_ci_lb_cisco_gss] table
    Field label and name Probes that gather data
    Serial Number [serial_number] Cisco GSS - Serial Number
    Model ID [model_id] Cisco GSS - Identity
    IP Address [ip_address] Cisco GSS - Network
    Manufacturer [manufacturer] Cisco GSS - Identity
    Table 3. Fields on the Cisco CSS [cmdb_ci_lb_cisco_css] table
    Field label and name Probes that gather data
    Serial Number [serial_number] SNMP - Load Balancer – Identity
    Model ID [model_id]
    IP Address [ip_address]
    Manufacturer [manufacturer]
    Table 4. Fields on the F5 BIG-IP [cmdb_ci_lb_bigip] table
    Field label and name Probes that gather data
    Active modules [active_modules]* SNMP - F5 BIG-IP - System
    Asset tag [asset_tag]
    Model ID [model_id]
    Failover mode [failover_mode]*
    Failover peer [failover_peer]*
    Serial Number [serial_number] Cisco GSS - Serial Number
    *not visible on the form by default. Customize the form to add this field.
    Table 5. Fields on the Load Balancer [cmdb_ci_lb] table
    Field label and name Probes that gather data
    Operational status [operational_status]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    • SNMP - Load Balancer - Identity
    Name [name]
    Table 6. Fields on the Load Balancer Application [cmdb_ci_lb_appl] table
    Field label and name Probes that gather data
    Configuration file [config_file]* Nginx - Get Configuration
    Name [name]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • Nginx - Get Configuration
    IP Address [ip_address]*
    Most recent discovery [last_discovered]*
    Version [version]
    • Apache - Version
    • HAProxy - Version
    • Nginx - Version
    Table 7. Fields on the Load Balancer Interface [cmdb_ci_lb_interface] table
    Field label and name Probes that gather data
    Status [install_status]*
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Load Balancer [load_balancer]
    Name [name]
    *not visible on the form by default. Customize the form to add this field.
    Table 8. Fields on the Load Balancer Pool [cmdb_ci_lb_pool] table
    Field label and name Probes that gather data
    Load Balancing Method [load_balance_method]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Load Balancer [load_balancer]
    Most recent discovery [last_discovered]*
    Name [name]
    *not visible on the form by default. Customize the form to add this field.
    Table 9. Fields for Load Balancer Pool Member [cmdb_ci_lb_pool_member] data
    Field label and name Probes that gather data
    Fully qualified domain name [fqdn]*
    • HAProxy - Get Configuration
    • Nginx - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    IP Address [ip_address]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • Nginx- Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Load balancer [load_balancer]
    Most recent discovery [last_discovery]*
    Name [name]
    Pool [pool]*
    Service Port [service_port]
    *not visible on the form by default. Customize the form to add this field.
    Table 10. Fields for Load Balancer Service [cmdb_ci_lb_service] data
    Field label and name Probes that gather data
    Input URL [input_url]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • Nginx - Get Configuration
    IP Address [ip_address]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • Cisco GSS - Identity
    • HAProxy - Get Configuration
    • Nginx - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Last port [last_port]* HAProxy - Get Configuration
    Load Balancer [load_balancer]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • Cisco GSS - Identity
    • HAProxy - Get Configuration
    • Nginx - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Most recent discovery [last_discovery]*
    Service Port [service_port]*
    *not visible on the form by default. Customize the form to add this field.
    Table 11. Fields for Load Balancer VLAN [cmdb_ci_lb_vlan] data
    Field label and name Probes that gather data
    Load Balancer [load_balancer]
    • Apache - Get JK Module
    • Apache - Get Proxy Module
    • HAProxy - Get Configuration
    • Nginx - Get Configuration
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System
    Name [name]
    Tag [tag]
    • SNMP - F5 BIG-IP - System
    • SNMP - Netscaler - System

    Apache web server data

    Discovery also collects data on Apache web serer load balancing modules using SSH. See Apache mod_jk and mod_proxy discovery for more information on probes for Apache web server data. For information on the tables, fields, and data sources that discovery populates for Apache web servers, see Apache web server discovery.