First, let’s see how we can create a symptom definition. vRealize Operations comes out of the box with more than 600 symptom definitions. I recommend you first spend some time getting yourself familiar with them as much as possible. Before creating a new one, make sure an existing definition doesn't exist that matches your needs, by using the symptom definition search and filter options vRealize Operations provides. Otherwise, you may end up creating new definitions when there is an already existing one which can satisfy your requirements.

For the purpose of this example, let’s say we have a company policy which states that we should be alerted if a VM is configured with more than 16 GB of memory. Let’s see how we can create a symptom definition to match that policy.

Perform the following steps to create a new symptom definition:

1. Go to the vRealize Operations User UI on the Master Replica node by navigating to the following URL: https://<FQDN or IP of the Master Replica Node>/ui. Navigate to the Alerts section and select Alert Settings, and then Symptom Definitions. Here we can see the symptoms on the right-hand side. Here is where we can tweak existing ones or create our own. Let's create our own so we can see what goes into a symptom definition. Click on the little green plus (+) icon, as shown in the following screenshot:

2. From the Base Object Type drop-down menu, navigate to vCenter Adapter and select Virtual Machine. Select Properties from the next drop-down menu. Navigate to Memory and select the VM Limit (KB) property.
3. Type a name for the definition. For example, Virtual Machine maximum memory configuration is violating corporate policies. From the Criticality drop-down menu, select Warning. From the matching criteria drop-down menu, select is greater than or equal to. Enter a value of 16384. Click Save:

This completes the process of creating a symptom definition.