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MID Server Basics

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In this lesson, you will learn:

  • What a MID Server is, and why it’s needed
  • How it talks to the instance through the ECC queue
  • How to check a MID Server’s status

1 Reaching inside the company network

Your ServiceNow instance lives in the cloud. But SNWR’s servers, databases, and directory are inside the company network, behind a firewall. How does ServiceNow reach them? With a MID Server. 🌉

Key term: MID Server

Management, Instrumentation, and Discovery Server. A small Java app installed on a computer inside the company network. It does work for the instance there, and sends back the results.

How a MID Server works. The SNWR instance is in the cloud. Inside the SNWR network, behind the firewall, is the MID Server, mid-snwr-01. Step 1: the instance puts a job in the ECC queue, like scan these servers. Step 2: the MID Server checks the queue over HTTPS, outbound only, and picks up the job. Step 3: it runs the job against internal systems like servers, a database, and the directory. Step 4: it puts the results back in the ECC queue. No inbound firewall ports are needed.
Figure 1. The MID Server reaches out to the instance, so the firewall stays closed to incoming traffic.

2 How it talks: the ECC queue

  • The instance puts work in the ECC queue (ecc_queue) as output records.
  • The MID Server checks in over HTTPS, picks up the work, and does it.
  • It sends the results back as input records.
  • Because the MID Server always starts the connection, no inbound firewall ports are needed.

3 What uses a MID Server

Feature Why it needs a MID Server
Discovery Scans internal servers and devices to find CIs (Lesson 44.1)
JDBC and LDAP imports Reads internal databases and directories (Lesson 43.1)
IntegrationHub and Orchestration Runs actions on internal systems
Service Mapping Maps how internal apps connect

4 Setting one up (overview)

  1. Create a user for the MID Server with the mid_server role.
  2. Download the installer from MID Server > Downloads and install it on a Windows or Linux computer inside the network.
  3. Enter the instance URL and the MID user’s login during setup.
  4. In MID Server > Servers, wait for status Up, then click Validate.

⚠️ Heads up: A MID Server that is Down or not Validated can’t do work. Discovery and imports that use it will wait or fail. Check its status first when something isn’t running.

⭐ Remember: MID Server = helper inside the network. Talks through the ECC queue, outbound HTTPS only. Must be Up and Validated.

5 Let’s try it: look around

  1. Open MID Server > Servers. Does your PDI have one? (Most PDIs don’t, and that’s fine.)
  2. Open MID Server > Downloads. Which operating systems are offered?
  3. Type ecc_queue.list in the filter navigator. Look at the Queue column: input or output?

6 Quick recap

  • A MID Server works inside the company network for the instance
  • It uses the ECC queue: output = work to do, input = results
  • It connects outbound over HTTPS, so no inbound ports are needed
  • Used by Discovery, JDBC/LDAP imports, IntegrationHub, and more
  • It must be Up and Validated

7 Check yourself

Think of your answer first. Then tap to check.

1 What does MID stand for? Show answer

Management, Instrumentation, and Discovery.

2 Which table carries work between the instance and the MID Server? Show answer

The ECC queue (ecc_queue).

3 Why don’t you need to open inbound firewall ports for a MID Server? Show answer

The MID Server starts the connection to the instance, outbound over HTTPS.

Nice work! You finished this lesson. 🎉

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