HAProxy load balancer discovery with patterns

Release version: Zurich

Updated July 31, 2025

3 minutes to read

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Summary of HAProxy load balancer discovery with patterns

The Discovery and Service Mapping Patterns application in ServiceNow uses the HAProxy pattern to discover HAProxy Community load balancers running on Linux servers. This open-source load balancer supports HTTP mode discovery, while TCP mode is not supported. Since version 1.15.0 of the Discovery and Service Mapping Patterns application, pattern-based discovery is the default method for identifying HAProxy load balancers.

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This discovery process supports a one-to-one relationship mapping between front-end and back-end ports, mapping only the lowest front-end port in cases where multiple front-ends share the same back-end.

Prerequisites

Ensure Discovery and Service Mapping Patterns and Visibility Content applications are updated to their latest versions.
Verify that HAProxy is installed and running on the target Linux server.
Confirm permission to execute the HAProxy version command (haproxy -v) and read access to the HAProxy configuration file (haproxy.cfg).
Create SSH credentials for Discovery to access the Linux server.
Schedule a horizontal discovery job to initiate the HAProxy discovery process.

Data Collected and CMDB Impact

During discovery, data is populated into the Configuration Management Database (CMDB) across several tables:

HAProxy Load Balancer [cmdbcilbhaproxy]: Captures the load balancer name, version, and a description derived from the HAProxy version command.
Load Balancer Service [cmdbcilbservice]: Stores the service name (formatted as <LB name>:<LB port>), listening port, IP address, highest port number used, and reference to the parent load balancer.
Load Balancer Pool [cmdbcilbpool]: Contains pool name, associated load balancer, load balancing method (e.g., Round Robin), install status, and last discovery timestamp.
Load Balancer Pool Member [cmdbcilbpoolmember]: Includes member name, service port, IP address, and references to both the pool and load balancer.

CI Relationships Created

Discovery automatically establishes key relationships among the discovered configuration items to represent the HAProxy load balancer architecture accurately:

Load Balancer Pool allocated to Load Balancer Service
Load Balancer Pool owns Load Balancer Pool Members
Load Balancer Pool and Load Balancer Pool Members reference the HAProxy Load Balancer
Load Balancer Service references the HAProxy Load Balancer and runs on specific hardware

Practical Benefits for ServiceNow Customers

This pattern-based discovery enables ServiceNow customers to automatically identify and map HAProxy Community load balancers within their environment, providing a detailed and structured view of load balancing infrastructure in the CMDB. It improves visibility into load balancer services, pools, and pool members, supporting accurate impact analysis and service mapping. Customers should ensure that prerequisites are met and that Discovery is properly configured to leverage this capability effectively.

The Discovery and Service Mapping Patterns application uses the HA Proxy pattern to find HAProxy Community load balancers running on a Linux server. Discovering some of these resources may require updating to the latest version of the Discovery and Service Mapping Patterns application from the ServiceNow Store.

HAProxy Community edition is an open-source load balancer that can run in either TCP or HTTP mode. Note that although Discovery supports HAProxy for HTTP load balancing, TCP load balancing isn’t supported.

Starting with Discovery and Service Mapping Patterns 1.15.0 version, pattern-based discovery is the default method for discovering HAProxy load balancers. For information on probe-based HAProxy discovery, see HAProxy load balancer discovery using probes.

Note:

HAProxy discovery supports one-to-one relationship mapping between a front-end port and a back-end port. If multiple front-ends are connected to the same back-end, the discovery process will only map the relationship from the lowest front-end port number in a defined range to the back-end port.

Request apps on the Store

Visit the ServiceNow Store website to view all the available apps and for information about submitting requests to the store. For cumulative release notes information for all released apps, see the ServiceNow Store version history release notes.

To learn about HAProxy load balancers and their versions that you can discover, refer to Detailed information on products discovered by ITOM Visibility.

Prerequisites

Verify that the applications are up to date

Discovery and Service Mapping Patterns
Visibility Content

Verify HAProxy is installed on the Linux server

Verify the HAProxy software is installed and running on a Linux server.

Verify permission to run HAProxy command

Verify you have permission to run the following command: <HAproxy Installation Path>/haproxy -v.

Verify read access to HAProxy configuration file

Verify you have read access to the haproxy.cfg file.

Create SSH credentials

For more information, see SSH credentials.

Schedule a horizontal discovery

For more information, see Schedule a horizontal discovery.

Data collected by Discovery during horizontal discovery

Discovery populates the data in the CMDB when running the HA Proxy Pattern.

Table 1. HAProxy Load Balancer [cmdb_ci_lb_haproxy]
Field	Description
Name [name]	Name of the HAProxy load balancer.
Version [version]	Version of the HAProxy load balancer.
Description [short_description]	Description of the HAProxy process, which is obtained by running the command: `haproxy -version`.

Table 2. Load Balancer Service [cmdb_ci_lb_service]
Field	Description
Name [name]	Name of the load balancer in the following format: `<LB name>:<LB port>`.
Port [port]	Port on which the load balancer is listening.
IP Address [ip_address]	IP address of the load balancer service.
Last port [last_port]	Highest port number used by the load balancer service.
Load balancer [load_balancer]	References the HAProxy Load Balancer [cmdb_ci_lb_haproxy] table.

Table 3. Load Balancer Pool [cmdb_ci_lb_pool]
Field	Description
Name [name]	Name of the load balancer pool.
Load balancer [load_balancer]	References the HAProxy Load Balancer [cmdb_ci_lb_haproxy] table.
Load balancing method [load_balancing_method]	Method used to load balance the pool, for example: Round Robin.
Most recent discovery [last_discovered]	Timestamp of the most recent discovery.
Install Status [install_status]	Install status of the load balancer pool, for example: Installed.

Table 4. Load Balancer Pool Member [cmdb_ci_lb_pool_member]
Field	Description
Name [name]	Name of the load balancer pool member.
Service port [service_port]	Port used by the pool member.
IP Address [ip_address]	IP address of the pool member host.
Pool [pool]	References the Load Balancer Pool [cmdb_ci_lb_pool] table.
Load balancer [load_balancer]	References the HAProxy Load Balancer [cmdb_ci_lb_haproxy] table.

CI relationships

Discovery creates these relationships to support the HAProxy load balancer discovery.


CI	Relationship	CI
Load Balancer Pool [cmdb_ci_lb_pool]	Allocated to::Allocated from	Load Balancer Service [cmdb_ci_lb_service]
Load Balancer Pool [cmdb_ci_lb_pool]	Owns::Owned by	Load Balancer Pool Member [cmdb_ci_lb_pool_member]
Load Balancer Pool [cmdb_ci_lb_pool]	References	HAProxy Load Balancer [cmdb_ci_lb_haproxy]
Load Balancer Pool [cmdb_ci_lb_pool]	References	Load Balancer Pool Member [cmdb_ci_lb_pool_member]
Load Balancer Pool Member [cmdb_ci_lb_pool_member]	References	HAProxy Load Balancer [cmdb_ci_lb_haproxy]
Load Balancer Service [cmdb_ci_lb_service]	References	HAProxy Load Balancer [cmdb_ci_lb_haproxy]
Load Balancer Service [cmdb_ci_lb_service]	Runs on::Runs	Hardware [cmdb_ci_hardware]