AWS classic ELB Service discovery

  • Release version: Yokohama
  • Updated January 30, 2025
  • 2 minutes to read
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    Summary of AWS classic ELB Service discovery

    The AWS classic ELB Service discovery pattern in ServiceNow enables customers to automatically find and map Amazon Elastic Load Balancers (ELBs) that handle HTTP and HTTPS traffic. It uses a top-down discovery approach starting from HTTP(s) or TCP endpoints, linking load balancers to their associated Amazon EC2 instances. This pattern supports discovery within both commercial AWS environments and Amazon Commercial Cloud Services (C2S), which is tailored for government intelligence community use.

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    The discovery pattern is compatible with ServiceNow Jakarta and later releases and integrates with ServiceNow’s AI Platform for cloud governance. It relies on the Configuration Management Database (CMDB) for storing discovered load balancer data, facilitating further service mapping and management.

    Prerequisites

    • Run a horizontal discovery using the Cloud API (CAPI) first, as the ELB pattern supports only top-down discovery.
    • Ensure load balancers are stored in the CMDB before creating application services for each load balancer.
    • Set read-only permissions for specific AWS REST APIs to describe load balancers and EC2 instances to create relations between them.
    • Download the Discovery and Service Mapping Patterns from the ServiceNow Store.
    • Install and configure the MID Server on a host machine that meets ServiceNow’s system requirements.
    • Refer to the Cloud Discovery patterns spreadsheet for user permissions and pattern details; keep it updated quarterly.
    • Test AWS REST APIs using tools like Postman to verify connectivity and permissions.

    Discovered Data and Practical Use

    The discovery captures detailed configuration items (CIs) related to load balancers and their network attributes, including:

    • Fully Qualified Domain Name (FQDN) and IP addresses of load balancers.
    • Ports used by load balancers and backend instances.
    • Protocols in use (HTTP, HTTPS).
    • Relations between load balancers and running EC2 instances.

    This detailed data enables ServiceNow customers to maintain an accurate, up-to-date CMDB reflecting their AWS ELB infrastructure, supporting better visibility, impact analysis, and cloud resource governance.

    Discovery uses the Amazon AWS classic ELB Service discovery pattern to find all load balancers that use HTTP and HTTPS traffic.

    Elastic Load Balancing (ELB) automatically distributes incoming application traffic across multiple targets.

    The Amazon AWS classic ELB Service discovery pattern supports top-down discovery. The two possible entry points for top-down discovery are the HTTP(s) Endpoint and TCP Endpoint. Outgoing relations are to Amazon EC2 instances.

    The ServiceNow AI Platform supports Amazon Commercial Cloud Services (C2S) for discovery and cloud governance. C2S is the government program that brings AWS into the Intelligence Community.

    You can use this pattern on the ServiceNow platform using Jakarta or later releases.

    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.

    Prerequisites

    • Run a horizontal discovery, using Cloud API (CAPI). This is necessary because this discovery pattern supports top-down discovery only. For cloud discovery, you can run the horizontal discovery as usual.
    • When the load balancers data has been stored in the Configuration Management Database (CMDB), create an application service for each load balancer.
    • Set read-only permissions for these REST APIs:
      • https://elasticloadbalancing.<REGION>.amazonaws.com/?Action=DescribeLoadBalancers&Version=2012-06-01&LoadBalancerNames.member.1=<LB_NAME>
      • https://ec2.<REGION>.amazonaws.com/?Action=DescribeInstances&Version=2016-11-15&Filter.1.Name=instance-state-name&Filter.1.Value=running&Filter.2.Name=instance-id&Filter.2.Value=<INSTANCE_ID> (to create relation between LB and EC2 instance)
    • For Cloud Discovery, download the Discovery and Service Mapping Patterns from the ServiceNow Store.
    • When installing the MID Server, ensure that the host machine meets or exceeds the MID Server system requirements published on the ServiceNow documentation site.

    Verify the REST API Permissions

    Download the Cloud Discovery patterns spreadsheet so you can grant user permissions required for running the Discovery patterns. In addition to permissions, the spreadsheet also includes useful information such as pattern names, types, CI Classes, and links to vendor documentation. New patterns are available quarterly, so check periodically to be sure you have the latest version of the spreadsheet.

    Note:
    You can test the AWS REST APIs using Postman API platform. For more information, see the How to test AWS REST API using POSTMAN [KB0782183] article in the Now Support Knowledge Base.

    Data collected by Discovery during horizontal discovery

    The discovered data includes the following tables and fields.

    Table and field Description
    Load Balancer Services [cmdb_ci_lb_service]
    Fully qualified domain name [fqdn] Fully Qualified Domain Name (FQDN) of the load balancer. The DNS name.
    Name [name] Name of the load balancer, in the following format: <LB name>:<LB port>.
    Back End Port [back_end_port] Port of the instance.
    Server Port [server_port] Port of the instance.
    Port [port] Port of the load balancer.
    Front End Port [front_end_port] Port of the load balancer.
    Object ID [object_id] LB port.
    IP Address [ip_address] IP address of the FQDN.
    Server Protocol [server_protocol] Protocol of the instance.
    IP Address [cmdb_ci_ip_address]
    IP Address [ip_address] IP address of the load balancer FQDN.
    Name [name] Name of the load balancer, in the following format: <LB name>:<LB port>.
    Netmask [netmask] 0.0.0.0