ServiceNow MID Server

How it works

• Every time a service or a host's state is checked, the event passes through Centreon Broker, which uses the functions defined in the Stream Connector to send state changes to ServiceNow MID Server.
• State changes can occur in case of an anomaly detection or metrics falling out of range.

Filters

Several filters have been set in the ServiceNow MID Server Stream Connector:

• Only services and hosts' status changes are processed
• Only the HARD state type are processed
• If the host or the service is in downtime, acknowledged, or if notifications are disabled, it's not processed
• Pending states are ignored

Data format

Here is an example of how the POST data are formatted by the Stream Connector for a host and a service event:

[
  {
    "message_key": "24/0/1596634138",
    "type": "HOST",
    "resource": "HOST",
    "metric_name": "HOST",
    "severity": 0,
    "source_instance": "Centreon central server",
    "description": "OK: dummy\n",
    "time_of_event": "2020-08-05T13:30:55.000",
    "source": "Centreon",
    "node": "test-host_10",
    "additional_info": {
      "host_groups": [
        "Test-Machines",
        "Serveurs-Linux",
        "gold"
      ]
    }
  },
  {
    "message_key": "24/93/1595260330",
    "type": "test-svc",
    "resource": "test-svc",
    "metric_name": "test-svc",
    "severity": 2,
    "source_instance": "Centreon central server",
    "description": "CRITICAL: sample output\n",
    "time_of_event": "2020-08-06T08:26:13.000",
    "source": "Centreon",
    "node": "test-host_10",
    "additional_info": {
      "host_groups": [
        "Test-Machines",
        "Serveurs-Linux",
        "gold"
      ],
      "service_groups": [
        "Groupe-de-Services",
        "Autre-groupe-de-services"
      ]
    }
  }
]

Requirements

• This integration requires at least one ServiceNow MID Server, and you must have been provided with one of the following types of account:
  • an account with evt_mgmt_admin privilege to be able to configure the event collector (according to Configure the MID WebService Event Collector Context).
  • an account entitled to log in to the JSONv2 API, whose URL looks like http://{MID_Server_IP}:{MID_Web_Server_Port}/api/mid/em/jsonv2.
• It is also necessary to use a Centreon account with either admin privileges or Export configuration and Broker configuration menu access in the WUI, as well as a root access in command-line interface.

Support

If you need help with this integration, depending on how you are using Centreon, you can:

• Commercial Edition customers: please contact the Centreon Support team.
• Open Source Edition users or Centreon IT-100 users (free versions): please reach our Community Slack where our users and staff will try to help you.

Integration Walkthrough

In ServiceNow MID Server

You can follow this link to find out how to configure the MID WebService Event Collector Context.

In Centreon

Installation

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

In case your Centreon central server must use a proxy server to reach the Internet, you will have to export the https_proxy environment variable and configure yum to be able to install everything.

export https_proxy=http://my.proxy.server:3128
echo "proxy=http://my.proxy.server:3128" >> /etc/yum.conf

Now that your Centreon central server is able to reach the Internet, you can run:

yum install -y lua-curl epel-release
yum install -y luarocks
luarocks install luatz

These packages are necessary to run the script. Now let's download the script:

wget -O /usr/share/centreon-broker/lua/servicenow-mid-server.lua https://raw.githubusercontent.com/centreon/centreon-stream-connector-scripts/master/servicenow/servicenow-mid-server.lua
chmod 644 /usr/share/centreon-broker/lua/servicenow-mid-server.lua

The ServiceNow MID Server StreamConnnector is now installed on your Centreon central server!

Broker configuration

1. Login to the Centreon WUI using an administrator account.
2. Navigate to the Configuration > Pollers menu and select Broker configuration.
3. Click on the central-broker-master broker configuration object and navigate to the Output tab.
4. Add a new Generic - Stream connector output.
5. Name it as you want (eg. ServiceNow) and set the right path for the LUA script: /usr/share/centreon-broker/lua/servicenow-mid-server.lua.
6. Add at least the following parameters:

Name	Type	Value
MID_Servers_List	String	Comma-separated MID Servers list with protocol and port (eg. http://srv1:80,https://srv2:443)
MID_Login	String	Login for basic authentication on MID Server JSON v2 API
MID_Password	String	Password for basic authentication on MID Server JSON v2 API

7. Save your configuration, then navigate to the Configuration > Pollers menu and select Pollers.
8. Select the Central poller and click on Export configuration.
9. Keep Generate Configuration Files and Run monitoring engine debug (-v) checked and select Move Export Files and then click on the Export button.
10. Restart the cbd service:

systemctl restart cbd

Now your central server has loaded the ServiceNow MID Server Stream Connector and has started to send data!

To make sure that everything goes fine, you should have a look at central-broker-master.log and stream-connector-snow-mid-server.log, both located in /var/log/centreon-broker.

Advanced configuration

Parameters table

Name	Type	Value example	Explanation
http_proxy_string	String	http://your.proxy.server:3128	Proxy string needed to reach the Internet in HTTP/HTTPS
log_level	Number	2 (default value)	Verbosity level for logs 0: errors only 1: +warnings, 2: +verbose, 3: +debug
log_path	String	/var/log/centreon-broker/my-custom-logfile.log	Log file full path and name
max_buffer_size	Number	1 (default value)	Number of events to enqueue in buffer before sending
max_buffer_age	Number	5 (default value)	Maximum number of seconds before sending an event when max_buffer_size hasn't been reached

Remarks

• The default value of 2 for log_level is fine for initial troubleshooting, but can generate a huge amount of logs if you monitor a lot of hosts. In order to get less log messages, you should tune this parameter.
• The default value of 1 for max_buffer_size works fine and ensures the best response times. You might want to tune it (ie. increase it) if you have an important amount of data to send to ServiceNow MID Server.

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How to Uninstall

1. Login to the Centreon WUI using an administrator account.
2. Navigate to the Configuration > Pollers menu and select Broker configuration.
3. Click on the central-broker-master broker configuration object and navigate to the Output tab.
4. Delete the Generic - Stream connector output by clicking on the red circled cross at the end of the line.
5. Save your configuration, then navigate to the Configuration > Pollers menu and select Pollers.
6. Select the Central poller and click on Export configuration.
7. Keep Generate Configuration Files and Run monitoring engine debug (-v) checked and select Move Export Files and then click on the Export button.
8. Restart the cbd service:

systemctl restart cbd

The Stream Connector is not loaded anymore!

9. Optionally, you can even delete the script file:

rm -f /usr/share/centreon-broker/lua/servicenow-mid-server.lua