Virtual server response processor example

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  • Updated February 1, 2024
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    Summary of Virtual Server Response Processor Example

    The CreateVirtualServerResponseProcessor script in Cloud Provisioning and Governance is designed to manage the creation of AWS virtual machine Configuration Items (CIs). This script automatically generates a virtual server record in the Virtual Machine Instance [cmdbcivminstance] table upon provisioning a new virtual server.

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    Key Features

    • Common Parameters: The script includes essential parameters that facilitate the processing of responses from the cloud provider, including cloudServiceAccountId, ldc, and correlationId.
    • JSON Parsing: The first step in the script is parsing the response into JSON format for easier processing of the data.
    • Identification of CIs: The script identifies new virtual servers and related CIs using specific object IDs, ensuring that no duplicates are created in the CMDB.
    • Attribute Population: It populates the cmdbcivminstance table with relevant attributes such as name, state, memory, and ipaddress.
    • References to Other CIs: The script can also reference other CIs, including OS templates and compute templates, by identifying their object IDs.

    Key Outcomes

    By utilizing the CreateVirtualServerResponseProcessor, ServiceNow customers can effectively automate the creation of AWS virtual machine records, ensuring accurate and up-to-date inventory in the CMDB. This process enhances operational efficiency while minimizing the risk of duplicate records, facilitating better cloud resource management.

    The Create_Virtual_Server_Response_Processor script, which is available by default in Cloud Provisioning and Governance, is the response processor that handles the creation of AWS virtual machine CIs.

    Create Virtual Server

    The Create_Virtual_Server_Response_Processor resource processor script is available by default on the Virtual Server resource block. Its job is to create a virtual server record in the Virtual Machine Instance [cmdb_ci_vm_instance] table when a new virtual server is provisioned.

    All response processors have this first line with these common parameters:
    function processResponse(response, cloudServiceAccountId, ldc, correlationId,step, requestorContext) {
    

    This brings in the response from the cloud provider and the important information, such as the account ID, that is required for the new CI that the system can create. All of these parameters are required for all response processors.

    Line 10 parses the response into JSON so that the system can process it. The information is held in the vmResponse variable:

    
    var vmResponse = global.JSON.parse(response);
    

    Whenever you create or edit a response processor, you must know which inputs are required for the CI type. Line 11 handles one of the necessary inputs, the hardware ID, that the CMDB record requires:

    
    var hardwareId = vmResponse.hardwareId;
    

    Line 39 shows the information that is required for the system to identify the new virtual server and related CIs, so the information can be put into the CMDB. In this case, the service account object ID identifies the account associated with the virtual server, the datacenter object ID identifies the datacenter in which the virtual server lives, and the virtual machine instance object ID identifies the virtual server itself. This identification code block prevents the creation of duplicate CIs.

    
    var vmInfo = {
        "cmdb_ci_vm_instance": {
          "validator": "virtual_machine_create_update_validator",
          "validator_overrides": {},
          "identification": {
            "cmdb_ci_cloud_service_account": {
              "criterion": {
                "object_id": cloudServiceAccountId
              }
            },
            "cmdb_ci_aws_datacenter": {
              "criterion": {
                "object_id": ldc
              }
            },
            "cmdb_ci_vm_instance": {
              "criterion": {
                "object_id": vmResponse.nodeId
              }
            }
          },

    Attributes are populated into the fields on in the cmdb_ci_vm_instance table. These attributes are defined in line 61:

    
    "attributes": {
      "name": vmResponse.nodeName,
      "object_id": vmResponse.nodeId,
      "state": status_map[vmResponse.state],
      "dns_suffix": vmResponse.dnsSuffix,
      "cpus": vmCPUs,
      "memory": vmMemory,
      "disks": vmResponse.volumes.length,
      "disks_size": "",
      "nics": vmResponse.networkInterfaces.length,
      "terminated_on": "",
      "termination_protection": "",
      "ip_address": vmPubIPAddr,
      "assigned_to": reqContext.userId,
      "assignment_group": reqContext.groupId
    },
    

    References to other CIs can also be included in the response processor. In this case, the OS template that the virtual server is based on is identified by first identifying the object ID of the service account and the datacenter along with the actual OS template.

    
    "references": {
      "cmdb_ci_os_template": {
        "identification": {
          "cmdb_ci_cloud_service_account": {
            "criterion": {
              "object_id": cloudServiceAccountId
            }
          },
          "cmdb_ci_aws_datacenter": {
            "criterion": {
              "object_id": ldc
            }
          },
          "cmdb_ci_os_template": {
            "criterion": {
              "object_id": imageIdTrim
            }
          }
        },

    The following code block adds the object ID of the OS image to the attributes list so that this information can be populated into the virtual server CMDB record.

    
    "attributes": {
      "object_id": imageIdTrim
    }
    

    This code block performs additional identification on the Compute template (the hardware type) and then add it to the attributes:

    
    "cmdb_ci_compute_template": {
      "identification": {
        "cmdb_ci_cloud_service_account": {
          "criterion": {
            "object_id": cloudServiceAccountId
          }
        },
        "cmdb_ci_aws_datacenter": {
          "criterion": {
            "object_id": ldc
          }
        },
        "cmdb_ci_compute_template": {
          "criterion": {
            "object_id": vmResponse.hardwareId
          }
        }
      },
      "attributes": {
        "object_id": vmResponse.hardwareId,
        "name": vmResponse.hardwareId
      }
    }

    Additional code sections make the relationship with network interfaces and identify any storage attached to the virtual server.

    This mandatory code block pushes the data to the CMDB and returns the JSON string:

    
    cloudModelString.push(vmInfo);
    return global.JSON.stringify(cloudModelString);