Pub/Sub Lite reports metrics to Cloud Monitoring. You can create alerting policies and charts of metrics using Cloud Monitoring.
Metrics and monitored resources
      A metric is a set of measurements about the behavior of a product, service, or application.
      For example, Pub/Sub Lite reports data for the backlog_quota_bytes
      metric.
    
For the complete list of Pub/Sub Lite metric types, see the list of Pub/Sub Lite metrics.
Pub/Sub Lite collects metrics from monitored resources, including the following:
Exploring metrics
To explore the metrics that Pub/Sub Lite reports to Cloud Monitoring, create a chart with the Metrics Explorer.
- 
          
In the Google Cloud console, go to the Metrics Explorer:
Go to the Metrics Explorer - 
          
            
In the Find resource type and metric pane, search for and select
pubsublite_subscription_partition. - 
          From the list of metrics, select 
backlog_quota_bytes. 
The Metrics Explorer creates temporary charts. To save a chart, add it to a dashboard.
Creating alerting policies
        An altering policy identifies a situation that warrants immediate attention or intervention.
        If metrics meet the conditions of an alerting policy, Cloud Monitoring sends you a
        notification. For example, Cloud Monitoring can notify you if
        backlog_quota_bytes is about to exceed a Pub/Sub Lite quota.
      
For more information about creating an alerting policy, see Introduction to alerting.
What's next
- Learn more about metrics and monitored resources.
 - Learn more about the Metrics Explorer.
 - Create and monitor groups of resources.
 - Create dashboards and charts.