Hi,
You cannot alert on the lack of data but the lack of data usually indicates that the agent is not reporting and is therefore disconnected. Fortunately there is a metric which holds the connection status for an agent and that has a value 1 for when the agent is connected and 3 for when it isn't.
The metric can be found at
Custom Metric Host (virtual)
- Custom Metric Process (virtual)
- Custom Metric Agent (virtual)(collector_host@port)(SuperDomain)
- Agents
- Host
- Process
- AgentName
and then looks at the values for ConnectionStatus.
Obviously in your environment you will need to know which collector the agent should be connected to and it may not always be the same one. So you can define a metric grouping to look for the value across all collectors i.e.
agent expression
(.)\|Custom Metric Process \(Virtual\)\|Custom Metric Agent \(Virtual\) .\)
metric expression
Agents\|host\|Process\|Agentname:ConnectionStatus
If that approach is viable then you can set up an alert on that grouping to notify when the connection status value becomes 3.
Thanks
Mike