How to switch back from using EMS to using NAS again

Products

• DX Unified Infrastructure Management (Nimsoft / UIM)
• Unified Infrastructure Management for Mainframe
• CA Unified Infrastructure Management SaaS (Nimsoft / UIM)

Issue/Introduction

We have configured our UIM DEV environment to process alarm messages via EMS upon recommendation via one of the support cases we opened, but it did resolve the issue we were having at that time. Now we are looking to fallback from EMS to NAS to match production. Please let us know the steps to switch back to NAS from EMS.

Cause

- Customer wanted EMS-focused configuration to be reverted back to NAS.

Environment

Release : 9.1.0

Component : UIM - EMS

Resolution

Out of the box/defaults you should see in the hub with nas and ems installed but not reconfigured for EMS, looks like this:

 

Quick checklist for message queue Subject names for nas and alarm_enrichment probes with NO EMS being used:

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1.alarm_enrichment probe uses a Subject of alarm

2.nas probe uses a Subject of alarm2

So by default, the alarm_enrichment probe uses the "alarm" Subject and forwards messages to the "alarm2" subject for the nas probe.

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Before ems deployment, alarm messages flow through the UIM environment in the following manner:

- probes and the baseline_engine send alarm messages with the Subject "alarm"

- The alarm_enrichment probe receives the alarm messages, enriches them with user-defined data, and then changes the alarm message subject to "alarm2"

- The nas probe receives the alarm2 message and performs further alarm processing

Post-reconfiguration, the alarm message Subjects used should be:

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1.alarm_enrichment probe: Change the enrichment_subject key via Raw Configure Mode from "alarm1" to "alarm"

2.nas probe continues to use a Subject of alarm2 (so normally no change is required here)

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In some cases, if you reconfigure UIM in favor of using the NAS, instead of the ems probe in your UIM environment:

The Alarm Routing Service is not automatically removed.

The enrichment_subject in the nas configuration file (nas.cfg) remains "alarm1"

Use the following procedure to ensure that no alarms are lost.

 

Follow these steps:

This procedure assumes that legacy alarm messages are currently being sent to the ems probe.

If you did not:

- Change the default routing destination to ems, and/or
- Configure any routing rules to send alarms to ems

Then-> Skip to step 3, otherwise:

1. In the Alarm Routing Service configuration file, change the default destination back to nas and remove any routing rules. This action prevents alarms from getting 'stuck' in the legacy_alarm queue
2. Enter the Raw Configure menu for the nas probe
3. Navigate to the setup folder 
4. Change the enrichment_subject key from "alarm1" to "alarm"
5. If you had deactivated the nas probe, deploy and reactivate it
6. Redeploy the correct ems version for your UIM version

Note that if you are running the spectrumgtw, you must have the ems probe installed on the Primary as well.

Additional Information

In some environments, if you run through the above process but after a restart of the nas/alarm_enrichment, the alarm_enrichment probe reverts back to a Subject of alarm1, follow these steps to avoid that issue:

1. Open nas probe in Raw Configure.
Please change value of "enrichment_subject" key (in setup section) from "alarm1" to "alarm", and save the change.

2. Deactivate trellis probe, delete trellis probe and delete probe folder (<UIM>/probes/service/trellis)

3. Deploy trellis probe to the Primary UIM hub and activate trellis probe.

4. Deploy nas-api-service package to the Primary UIM hub (applies to UIM v9.02 or earlier releases)

5. (Spectrum Gateway probe Users only!) Deploy Spectrum UIM Services package to the Primary UIM hub.

(*) The version of Spectrum UIM Services package should match the version of Spectrum Gateway probe.

6. Open hub probe GUI in the Primary hub, go to [Queues] tab, highlight [alarm-routing-service] queue, delete the queue and save it.