Create an error count threshold rule

Create an error count threshold rule to alert you when the number of errors in a service exceeds a defined threshold. Threshold rules can be set at different levels: environment, service, transaction type, and/or transaction name.

To create your error count threshold rule:

1. In the Observability UI, go to Alerts.
2. Select Manage Rules from the Alerts page, and select Create rule.
3. Enter a Name for your rule, and any optional Tags for more granular reporting (leave blank if unsure).
4. Select the Error count threshold rule type from the APM use case.
5. Select the appropriate Service, Environment, and Error Grouping Key (or leave ALL to include all options). Alternatively, you can select Use KQL Filter and enter a KQL expression to limit the scope of your rule.
6. Enter the error threshold in Is Above (defaults to 25 errors).
7. Define the period to be assessed in For the last (defaults to last 5 minutes).
8. Choose how to Group alerts by. Every unique value will create an alert.
9. Define the interval to check the rule (for example, check every 1 minute).
10. (Optional) Set up Actions.
11. Save your rule.

You can extend your rules with actions that interact with third-party systems, write to logs or indices, or send user notifications. You can add an action to a rule at any time. You can create rules without adding actions, and you can also define multiple actions for a single rule.

To add actions to rules, you must first create a connector for that service (for example, an email or external incident management system), which you can then use for different rules, each with their own action frequency.

Action frequency

After you select a connector, you must set the action frequency. You can choose to create a Summary of alerts on each check interval or on a custom interval. For example, you can send email notifications that summarize the new, ongoing, and recovered alerts every twelve hours.

Alternatively, you can set the action frequency to For each alert and specify the conditions each alert must meet for the action to run. For example, you can send an email only when the alert status changes to critical.

With the Run when menu you can choose if an action runs when the threshold for an alert is reached, or when the alert is recovered. For example, you can add a corresponding action for each state to ensure you are alerted when the rule is triggered and also when it recovers.

Action variables

Use the default notification message or customize it. You can add more context to the message by clicking the Add variable icon and selecting from a list of available variables.

The following variables are specific to this rule type. You can also specify variables common to all rules.

context.alertDetailsUrl

Link to the alert troubleshooting view for further context and details. This will be an empty string if the server.publicBaseUrl is not configured.

context.environment

The transaction type the alert is created for.

context.errorGroupingKey

The error grouping key the alert is created for.

context.errorGroupingName

The error grouping name the alert is created for.

context.interval

The length and unit of time period where the alert conditions were met.

context.reason

A concise description of the reason for the alert.

context.serviceName

The service the alert is created for.

context.threshold

Any trigger value above this value will cause the alert to fire.

context.transactionName

The transaction name the alert is created for.

context.triggerValue

The value that breached the threshold and triggered the alert.

context.viewInAppUrl

Link to the alert source.

The error count threshold alert triggers when the number of errors in a service exceeds a defined threshold. Because some errors are more important than others, this guide will focus a specific error group ID.

Before continuing, identify the service name, environment name, and error group ID that you’d like to create an error count threshold rule for.

This guide will create an alert for an error group ID based on the following criteria:

• Service: {your_service.name}
• Environment: {your_service.environment}
• Error Grouping Key: {your_error.ID}
• Error count is above 25 errors for the last five minutes
• Group alerts by service.name and service.environment
• Check every 1 minute
• Send the alert via email to the site reliability team

From any page in Applications, select Alerts and rules → Create threshold rule → Error count rule. Change the name of the alert (if you wish), but do not edit the tags.

Based on the criteria above, define the following rule details:

• Service: {your_service.name}
• Environment: {your_service.environment}
• Error Grouping Key: {your_error.ID}
• Is above: 25 errors
• For the last: 5 minutes
• Group alerts by: service.name service.environment
• Check every: 1 minute

Next, select the Email connector and click Create a connector. Fill out the required details: sender, host, port, etc., and select Save.

A default message is provided as a starting point for your alert. You can use the Mustache template syntax ({{variable}}) to pass additional alert values at the time a condition is detected to an action. A list of available variables can be accessed by clicking the Add variable icon .

Select Save. The alert has been created and is now active!