ServiceNow Event Manager

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Before starting

• You can send events from a central server, a remote server or a poller.
• By default, this stream connector sends host_status and service_status events. The event format is shown there.
• Aformentioned events are fired each time a host or a service is checked. Various parameters let you filter out events.

Installation

Login as root on the Centreon central server using your favorite SSH client.

Run the command according on your system:

Alma / RHEL / Oracle Linux 8

dnf install centreon-stream-connector-servicenow

Alma / RHEL / Oracle Linux 9

dnf install centreon-stream-connector-servicenow

Debian_11

apt install centreon-stream-connector-servicenow

Configuration

To configure your stream connector, you must head over the configuration --> Poller --> Broker configuration menu. Select the central-broker-master configuration (or the appropriate broker configuration if it is a poller or a remote server that will send events) and click the Output tab when the broker form is displayed.

Add a new generic - stream connector output and set the following fields as follow:

Field	Value
Name	Servicenow events
Path	/usr/share/centreon-broker/lua/servicenow-em-events-apiv2.lua
Filter category	Neb

Add Service Now mandatory parameters

Each stream connector has a set of mandatory parameters. To add them you must click on the +Add a new entry button located below the filter category input.

Type	Name	Value explanation	Value exemple
string	instance	the name of the service now instance	MyCompany
string	client_id	The Oauth client_id
string	client_secret	The Oauth client_secret
string	username	The Oauth user
string	password	The Oauth pasword

Add Service Now optional parameters

Some stream connectors have a set of optional parameters dedicated to the Software that they are associated with. To add them you must click on the +Add a new entry button located below the filter category input.

Type	Name	Value explanation	default value
string	logfile	the file in which logs are written	/var/log/centreon-broker/servicenow-em-stream-connector.log
number	log_level	logging level from 1 (errors) to 3 (debug)	1

Standard parameters

All stream connectors can use a set of optional parameters that are made available through Centreon stream connectors lua modules.

All those parameters are documented here.

Some of them are overridden by this stream connector.

Type	Name	Default value for the stream connector
string	accepted_categories	neb
string	accepted_elements	host_status,service_status

Event bulking

This stream connector is compatible with event bulking. Meaning that it is able to send more that one event in each call to the Service Now REST API.

To use this feature you must add the following parameter in your stream connector configuration.

Type	Name	Value
number	max_buffer_size	more than one

Event format

This stream connector will send event with the following format.

service_status event

{
  "records": [{
    "source": "centreon",
    "event_class": "centreon",
    "severity": 5,
    "node": "my_host",
    "resource": "my_service",
    "time_of_event": "2022-09-06 11:52:12",
    "description": "CRITICAL: USB cable behaving like a water hose"
  }]
}

host_status event

{
  "records": [{
    "source": "centreon",
    "event_class": "centreon",
    "severity": 5,
    "node": "my_host",
    "resource": "my_host",
    "time_of_event": "2022-09-06 11:52:12",
    "description": "DOWN: someone plugged an UPS on another UPS to create infinite energy"
  }]
}

Custom event format

This stream connector allows you to change the format of the event to suit your needs. Only the records part of the json is customisable. It also allows you to handle events type that are not handled by default such as ba_status events.

In order to use this feature you need to configure a json event format file and add a new stream connector parameter.

Type	Name	Value
string	format_file	/etc/centreon-broker/servicenow-em-events-format.json

The event format configuration file must be readable by the centreon-broker user

To learn more about custom event format and templating file, head over the following documentation.

Curl commands

Here is the list of all the curl commands that are used by the stream connector.

You must replace all the <xxxx> inside the below commands with their appropriate value. <instance> may become MyCompany.

Get OAuth tokens

curl -X POST -H "Content-Type: application/x-www-form-urlencoded" 'https://<instance_name>.service-now.com/oauth_token.do' -d 'grant_type=password&client_id=<client_id>&client_secret=<client_secret>&username=<username>&password=<password>'

Refresh OAuth tokens

curl -X POST -H "Content-Type: application/x-www-form-urlencoded" 'https://<instance_name>.service-now.com/oauth_token.do' -d 'grant_type=refresh_token&client_id=<client_id>&client_secret=<client_secret>&username=<username>&password=<password>&refresh_token=<refresh_token>'

The <refresh_token> is obtained thanks to this curl.

Send events

curl -X POST -H 'content-type: application/json' -H 'Accept: application/json' -H 'Authorization: Bearer <access_token>' 'https://<instance_name>.service-now.com/api/global/em/jsonv2' -d '{"records":[{"source": "centreon","event_class": "centreon","severity": 5,"node": "my_host","resource": "my_service","time_of_event": "2022-09-06 11:52:12","description": "CRITICAL: USB cable behaving like a water hose"}]}'

The <access_token> is obtained thanks to this curl.