If data loss occurs during a collection process, Log Service can receive no data, and this issue may not be noticed. Therefore, Log Service provides the no-data alert feature to alert this type of issue.

For example, you can configure an alert monitoring rule to monitor the CPU metrics for each host. If the following conditions are met, an alert is triggered, and an alert notification is sent:
  • The CPU utilization of a host exceeds 95%.
  • No data exists in the query and analysis result.
Configure the alert monitoring rule based on the following description:
  • Query Statistics: Specify * | select promql_query_range('cpu_util') from metrics limit 1000.

    This query statement is used to query the CPU utilization of the hosts.

  • Trigger Condition: Select data matches the expression, enter value>95, and then select Severity: Medium.

    If the value field in the query and analysis result is greater than 95, an alert of medium severity is triggered.

  • Threshold of Continuous Triggers: If the number of consecutive times the specified trigger condition is met reaches the value of this parameter, an alert is triggered.
  • No Data Alert: Turn on No Data Alert, and configure the Severity and Add Annotation parameters.

    If you turn on No Data Alert, an alert is triggered when the number of consecutive times no data is returned exceeds the value of Threshold of Continuous Triggers.

    If you turn on No Data Alert, you must specify an independent severity and annotations for this feature.

No-data alert