MID Server

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Note
Note: This article applies to Fuji and earlier releases. For more current information, see MID Server at http://docs.servicenow.com

The ServiceNow Wiki is no longer being updated. Visit http://docs.servicenow.com for the latest product documentation.


1 Overview

The Management, Instrumentation, and Discovery (MID) Server is a Java application that runs as a Windows service or UNIX daemon. The MID Server facilitates communication and movement of data between the ServiceNow platform and external applications, data sources, and services.

For specific requirements for using the MID Server with Discovery, see MID Server Requirements for Discovery. See the following pages for installation and configuration information:

The MID Server performs the following tasks:

  • Communicates securely with the ServiceNow instance to determine what Discovery probes to run
  • Runs Discovery probes on the local network to gather data on network devices
  • Sends Discovery probe results back to the ServiceNow instance for processing
Note
Note: MID Server communications are initiated inside the enterprise's firewall and therefore do not require any special firewall rules or VPNs.


2 Functional Architecture

The MID Server is a Java process that oversees 2 main functional groups of sub-processes, namely Monitors and Workers. A Monitor runs in a separate thread as a timer object and is configured to execute a task periodically, returning its result to ServiceNow's ECC Queue (External Communication Channel Queue). A Worker is an on-demand thread that executes a task when a corresponding ECC output queue record is read from ServiceNow (The Queue Monitor reads the ECC output queue and triggers a Worker). For example, a Discovery probe is a Worker.

Monitors

  1. Auto Upgrade
  2. Heartbeat
  3. Queue Monitor
  4. Queue Sender
  5. Synchronizers
    • Altiris
    • LanDesk
    • Microsoft SMS
    • JDBC

Workers

  1. Command Line
  2. JDBC
  3. File
  4. Probes
    • HTTP
    • WMI
    • SNMP
    • SSH

2.1 JAR File Synchronization

An administrator can upload a JAR file to an instance and synchronize it to all MID Servers. The administrator can then write custom probes that use the synchronized JAR file. To upload a JAR file to the instance:

  1. Navigate to MID Server > JAR Files.
  2. Click New.
  3. Complete the following fields:
    • Name: A unique and descriptive name for identifying the file in the instance.
    • Version: A version number for the file, if one is available.
    • Source: Location of the JAR file for reference purposes. Source information is not used by the system.
    • Description: Short description of the JAR file and its purpose in the instance.
  4. Click the paper clip icon in the banner and attach the JAR file to the record.

    JAR_File_Sync.png

  5. Click Submit.
  6. Restart the MID Server service.
    The platform makes the JAR file available to any MID Server configured to communicate with the instance.

3 System Requirements

ServiceNow has tested the MID Server in the following environments:

  • Windows Server 2003, 2008, and 2012. All Windows Server 2008 and 2012 editions are supported. Virtual machines and 64-bit systems are supported.
  • Linux: Virtual machines and 64-bit systems are supported. On 64-bit Linux systems, you must install the 32-bit GNU C library (glibc). The installation command for CentOS is: yum install glibc.i686

The minimum suggested configuration is:

  • 4GB of available RAM per MID Server
  • 2+GHZ CPU (Multi-core preferred)
  • 500MB of disk space per MID Server
  • Can ride-along with other services (dependent on server utilization and resource availability)

3.1 Java Version Support

The MID Server installs with JRE version 1.8. If you upgrade with a MID Server using JRE 1.6, the system automatically upgrades that MID Server to use version 1.8. Both the 32 bit and 64 bit MID Server use JRE 1.8.

4 Applications

The MID Server is used by the following applications:

5 Reports

The following global reports are available for MID Server analytics (starting with the Eureka release).

  • MID: Avg Max Memory Percent Use Last 30 Days
  • MID Host: Avg CPU Use Percent Per Last 30 Days

6 MID Servers and System Clones

See KB0547597 for a information on what to do with MID servers when you are cloning your instance.

7 Enhancements

7.1 Fuji

  • The following records can no longer be modified or deleted:
Table Record
Public Page [sys_public] InstanceInfo
Scripted Web Service [sys_web_service]
  • InstanceInfo
  • GetMIDInfo
  • MIDAssignedPackages
  • MIDFieldForFileProvider
  • MIDFileSyncSnapshot
  • MIDServerCheck
  • MIDServerFileProvider

7.2 Eureka

  • MID Server upgrades support an HTTPS connection over port 443.
  • Provides a new SSH client with improved connectivity.
  • Provides new reports for MID Server analytics.

7.3 Dublin

  • Administrators can install a 64-bit MID Server on a 64-bit host system.
  • Script File synchronization stores all MID Server scripts in the ServiceNow instance to simplify distribution and security. It is no longer necessary to manually unblock MID Server scripts on the host machine.
  • Several new business rules ensure that changing a MID Server's name in the configuration parameter also changes the name in MID Server record. See Available Parameters.
  • The first MID server to successfully connect with the ServiceNow instance automatically becomes the default MID Server.
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