MID Server selection

You can configure applications to select MID Servers in a variety of ways.

MID Server criteria

MID Servers offer these types of criteria that help an application determine which MID Server to use:
  • Application: the ServiceNow application that you specify on the MID Server (starting with the Istanbul release). You can designate these applications for a specific MID Server:
    • Discovery
    • Orchestration
    • Service Mapping
    • Service Analytics
    • Event Management
    • Cloud Management

    An ALL application option is also available. By default, the ALL option includes all applications except Service Analytics, which requires an exclusive MID Server. You can configure which applications are included in ALL.

  • IP address or range: The IP address or the IP ranges that the MID Server is allowed to work within. You specify an IP address or IP range in two places: in the application, such as on a Discovery schedule or an Orchestration activity, and on the MID Server. If the IP configured in the application matches the IP address or falls within the allowable IP range configured on the MID Server, a match is possible and that MID Server passes this criteria.
  • Capabilities: the network capability an application needs to use, such as the Powershell Orchestration activity. Discovery does not use capabilities.
    Note: Discovery and Service Mapping can also use behaviors that determine the type of port probes used during the port scan phase of discovery. Both Discovery and Service Mapping use a behavior to discover load balancers running on Linux. Other applications do not use behaviors. Behaviors are not used for auto-selection, default MID Servers, or specific MID Servers as described below.

How an application selects a MID Server

If you do not specify a specific MID Server for an application to use, the application tries to select one. Each application relies on different criteria to select an appropriate MID Server.
Application Supported Application on the MID Server IP address range Capability
Discovery

(Select Auto-Select MID Server on the Discovery schedule)

The Discovery or ALL application must be specified on the MID Server. Discovery uses IP ranges that you configure on the discovery schedule to see if they fall within the IP ranges that you configure on the MID Server, or the ALL IP ranges option must be selected on the MID Server. not applicable
Note: Any configured behaviors are ignored.
Orchestration The Orchestration or ALL application must be specified on the MID Server. The target IP address that you configure in an Orchestration activity must fall within the IP ranges that you configure on the MID Server, or the ALL option must be selected on the MID Server. The capability that is required for an Orchestration activity must match the capabilities you configure on the MID Server, or the MID Server capability must be set to ALL.
Service Analytics The Service Analytics application must be specified on the MID Server. not applicable One of these capabilities must be present on the MID Server: the RCA capability for Service Analytics and the ITOA metrics capability for operational metrics.
Service Mapping The Service Mapping or ALL application must be specified on the MID Server. The endpoint IP address must fall within the IP ranges that you configure on the MID Server, or the ALL option must be selected on the MID Server.

One of the supported Service Mapping capabilities (for new installs) must be configured on the MID Server, or the MID Server capability must be set to ALL. Functionality differs for new installs and upgrades.

Event Management The Event Management or ALL application must be specified on the MID Server. The IP configured in the event connector instances, such as HPOM, must fall within the IP ranges configured on the MID Server.

Specifying a default MID Server for each application

A default MID Server is the last choice MID Server that an application uses if it cannot find a suitable MID Server during auto selection. You specify a default MID Server on the application record for all applications except Event Management. The default MID Server for the ALL application is used if the default MID Server for the specific application is not available. Some applications also offer a property to set the default MID Server.

The default MID Server does not need to meet any criteria (application, IP range, behavior, or capability) to be used. Specifying a default MID Server is optional, and you can use a MID Server as the default for more than one application.
Application Additional notes
Discovery Discovery attempts to use the default MID Server when the discovery schedule specifies Auto-Select MID Server and Discovery cannot find any MID Servers with the correct application and IP range.
Orchestration Orchestration attempts to use the default MID Server when it cannot find any MID Servers with the capabilities that you define in the Orchestration activity.

You can also specify a default MID Server using a property. The value in that property automatically synchronizes with the default MID Server you select in the Orchestration application.

Service Analytics Not applicable. The MID Server is selected if it has the RCA capability. Route to right MID by domain.
Service Mapping Starting with the Istanbul release, fresh Istanbul installs use the default MID Server for the Service Mapping application. Upgrades to Istanbul still use the MID Server in the mid.server.sm_default property.
Event Management You can also specify a default MID Server for using the mid.server.connector_default property. Event Management does not use the default MID Server in the application record.

Using a specific MID Server

Discovery and Event Management can use a MID Server that you specifically call out.

Note: Selecting a specific MID Server is not the same as specifying the default MID Server for an application. A specific MID Server is always used. If it is Down or not validated, the application does not execute commands against the MID Server. A default MID Server is fallback that is used when the auto-selection of MID Servers does not find any eligible MID Server.
Application How you specify a specific MID Server Criteria that the default MID Server must meet
Discovery Choose the MID Server on the Discovery schedule.
Note: You an also specify a cluster of MID Servers.
You can use any MID Server as long as it does not have the RCA capability for Service Analytics. If you select a MID Server without the Discovery or ALL application, it automatically adds the Discovery application.
Orchestration Not applicable Not applicable
Service Analytics Not applicable Not applicable
Service Mapping Not applicable Not applicable
Event Management Choose one or more MID Servers on the connector instance event collection, such as HPOM. Not applicable
Note: If a MID Server manages resources within defined IP ranges for Orchestration, you must map the fully-qualified domain name (FQDN) of a server with its IP address to run certain activities, such as Exchange activities.

Upgrading to Istanbul

When you upgrade to Istanbul, the upgrade scripts attempt to generate the necessary application records. For information on the changes that are made when you upgrade to Istanbul, see MID Server upgrade to the Istanbul release.

Domain separation

If you are using domain separation, you can configure MID Servers to be in separate domains. The domain that the MID Server is in affects how the application selects the domain:
  • Discovery and Service Mapping: On the Discovery schedule, the MID Servers and clusters that available for selection are limited to the same domain of the user who is configuring the schedule. This also applies to the auto-selection option: only MID Servers in the same domain as the user can be automatically selected.
  • Service Analytics: The metrics for a business service is done on the MID Server that is in the same domain as the business service. Otherwise, a MID Server from the global domain is used.