HAProxy load balancer discovery using probes

  • Release version: Xanadu
  • Updated August 1, 2024
  • 2 minutes to read
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    Summary of HAProxy Load Balancer Discovery Using Probes

    Discovery of HAProxy Community edition load balancers is performed via SSH, with pattern-based discovery being the default method since version 1.15.0. Customers can enable probe-based discovery by following specific guidelines. This method is essential for accurately discovering and managing HAProxy load balancers within the ServiceNow environment.

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    Key Features

    • HAProxy Compatibility: Designed for HTTP load balancing, it supports session persistence and Layer 7 processing. TCP load balancing is not supported.
    • Discovery Requirements: HAProxy must be installed on a Linux server with the MID Server deployed and configured to access the HAProxy configuration file.
    • Probes Utilized: The discovery process employs various probes to gather critical information, including:
      • HAProxy – Version: Captures the HAProxy version.
      • HAProxy – Get Configuration: Gathers additional configuration details, populating multiple related tables.
    • Process Identification: The Unix - Active Processes probe is used to identify the HAProxy process, creating a record if one does not already exist.

    Key Outcomes

    Upon successful discovery, the following happens:

    • Records are created in the HAProxy Load Balancers table and related tables, including Load Balancer Service, Pool, Pool Member, Interface, and Application.
    • Establishes relationships between various configuration items, aiding in comprehensive management and oversight of the HAProxy environment.

    Discovery of HAProxy Community edition load balancers is performed by SSH.

    Note:
    Starting with Discovery and Service Mapping Patterns 1.15.0 version, pattern-based discovery is the default method for discovering HAProxy load balancers.

    HAProxy is an open-source load balancer that can manage any TCP service. It is particularly suited for HTTP load balancing because it supports session persistence and Layer 7 processing. Discovery supports HAProxy for HTTP load balancing. TCP load-balancing is not supported.

    Consider the following requirements for discovering the HAProxy:
    • The HAProxy software is installed and running on a Linux server.
    • The MID Server is deployed to explore the server and the MID Server has access to the server HAProxy configuration file.
    • The configuration probe checks for the haproxy.cfg file using one of the following methods:
      • Using the f parameter for the HAProxy process output.
      • Using the default /etc/haproxy/haproxy.cfg path.
    • The HAProxy probes require credentials and execute privileges to run commands.

    Discovery uses the Unix - Active Processes probe to identify an HAProxy load balancer when the name of the process is haproxy. If this criterion matches, a record is created in the HAProxy Load Balancers [cmdb_ci_lb_haproxy] table if one does not already exist for that running process.

    The following probes are triggered after classification:
    Table 1. HAProxy probes
    Probe Description Commands
    HAProxy – Version The sensor of this probe populates the HAProxy version in the HAProxy Load Balancers [cmdb_ci_lb_haproxy] table. haproxy
    HAProxy – Get Configuration The sensor of this probe populates additional information in the HAProxy Load Balancers [cmdb_ci_lb_haproxy] table. The probe also populates information in the Load Balancer Service [cmdb_ci_lb_service], Load Balancer Pool [cmdb_ci_lb_pool], Load Balancer Pool Member [cmdb_ci_lb_pool_member], Load Balancer Interface [cmdb_ci_lb_interface], and Load Balancer Application [cmdb_ci_lb_appl] tables. echo, sed, cut, grep, egrep (within the Borne shell script)

    In addition to populating the data, the following relationships records are created in CI Relationships [cmdb_rel_ci] table:

    • The records in the cmdb_ci_lb_appl table run on the cmdb_ci_web_server table records.
    • The records in the cmdb_ci_lb_service table use the cmdb_ci_lb_pool table records.
    • The records in the cmdb_ci_pool table are used by the cmdb_ci_service table records.
    • The records in the cmdb_ci_pool table are members of the cmdb_ci_pool_member table records.
    • The records in the cmdb_ci_pool_member table are members of the cmdb_ci_pool table records.