Configuring the Disco plug-in

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By default the Disco plug-in triggers rediscovery of devices associated with reboot events from the Tivoli Netcool/OMNIbus ObjectServer. You can configure the Disco plug-in to trigger rediscovery based on the receipt of any event.

About this task

By default, only reboot events (events with an eventId field set to NmosSnmpReboot) are passed to the Disco plug-in. In order to pass events with a different eventId field value to the Disco plug-in, any one of the following methods can be used:

Assign a different eventId to the existing Reconfiguration event map using one of the following event selection methods:
- Configure the relevant IBM Tivoli Netcool/OMNIbus probe rules files.
- Populate the Event Gateway config.precedence table using an appropriate insert.
This can be done if the LocalNodeAlias of the event identifies the chassis, or if the NmosEntityId is set.
Note: By default, the Reconfiguration event map does not pass events to the RCA plug-in for root-cause analysis. Do not use this method if the events to be passed to the Disco plug-in also need to be considered for root-cause analysis (RCA).
Register an existing event map with the Disco plug-in, using the script ncp_gwplugins.pl.
Note: All events using this existing event map will be passed to the Disco plug-in. Do not use this method if there are any events that use the existing map that must not trigger rediscovery.
Create a new event map, assign the events with a particular eventId field value to that event map, and register the new event map with the Disco plugin, using the script ncp_gwplugins.pl. This is the method presented in the example that follows.

Configuring the Disco plug-in to respond to any event

This example assumes that there exists an event type, that is, a group of events with the same eventId field value, that contains an IP address in the LocalNodeAlias field. There is a requirement to consider this event type for RCA and also be able to rediscover the entities associated with events of this event type.

Add a new event map to the EventGatewaySchema.cfg file, with an appropriate lookup stitcher. The existing LookupMainNode stitcher will select a chassis from an IP. This example assumes that the name of the new event map is NewEventMap.
Note: The EventGatewaySchema.cfg file is located at: $NCHOME /etc/precision/EventGatewaySchema.cfg.
```
insert into config.eventMaps 
(
    EventMapName,
    Stitcher
)
values
(
    "NewEventMap",
    "LookupMainNode"
);   
```
Associate the event type with the new event map by configuring the relevant probe rules file to populate the field NmosEventMap with the name of the new event map, NewEventMap.
Note: Configuring the probe rules file is the preferred way of associating the event with the new event map, as this method updates the event at source, and therefore the change to the event map is automatically detected by the Netcool/OMNIbus Knowledge Library and by all Network Manager installations that connect to the Tivoli Netcool/OMNIbus ObjectServer to which the probe is connected. Where EventId is the event identifer for the event type to be handled by the new event map.
1. On the server where the Netcool/OMNIbus Knowledge Library is installed, locate the rules file that corresponds to the eventID of the type of events that you want to customize. For vendor-specific rules, the rules files are placed under the vendor directory, for example, include-snmptrap/cisco.
2. Locate the appropriate rules file with the suffix user.include.rules. For example, /include-snmptrap/adtran/adtran-ADTRAN-ACTDAXL3-MIB.user.include.snmptrap.rules. Putting your customizations in a separate file makes it easier to identify and back them up later.
3. Edit the file and locate the section that corresponds to the type of trap that you want to customize.
4. Set the @NmosEventMap field using the following format: event map name.precedence value. For example:
```
@NmosEventMap = "NewEventMap.0"
```

Alternatively if you are unable to make changes to the probe rules file, then you can associate the event with the new event map by add a config.precedence insert to the EventGatewaySchema.cfg file, as in the following example:

# Precedence of 0 implies this event cannot suppress others
# 'MyEventId' should be the EventId field of the event in the Omnibus alerts.status table
insert into config.precedence
(
    Precedence,
    EventMapName,
    NcoEventId
)
values
(
    0,
    "NewEventMap",
    "EventId"
);

Configure the Disco and RCA plug-ins to subscribe to the new event map by running the following commands. This ensures that the event type of interest is considered as a candidate for suppression in RCA and is used to trigger rediscovery of the entity associated with the event.
```
ncp_gwplugins.pl -domain domain -plugin Disco -add -eventMap NewEventMap
ncp_gwplugins.pl -domain domain -plugin RCA -add -eventMap NewEventMap
```
Where domain is the current domain.
Perform the following verification operations:
- Verify the plug-in configuration by running the following commands:
```
ncp_gwplugins.pl -domain domain -plugin Disco
ncp_gwplugins.pl -domain domain -plugin RCA
```
  The responses to each of these commands should show that the plug-in subscribes to the NewEventMap event map.
- Verify the event map configuration by running the following command:
```
ncp_gwplugins.pl -domain domain -eventMap NewEventMap
```
  The responses to this commands should show that the NewEventMap event map is subscribed to by the Disco and RCA plug-ins.