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# Create Circuit Breaking Rules

Circuit breaking rules can monitor the response time or exception ratio of internal or downstream services in an application. When a specified threshold is reached, the priority of the downstream dependencies is reduced, and lower-priority unstable resources are not called within a specified time range. This helps prevent the application from being affected, ensuring high availability. After a circuit breaker's duration ends, it enters a probing recovery state: if the response time of the next request is less than the set slow call maximum response time, the circuit is closed; otherwise, the resource will be circuit broken again.

Follow the steps below to create a circuit breaking rule:

1. Click the name of the target managed registry, then click __Microservices__ in the left sidebar and click the  __Governance__ option on the right side.

    > Note that the microservice you want to govern should have the "Can be governed" status set to "Yes" in order to proceed with the following steps.

    ![](https://docs.daocloud.io/daocloud-docs-images/docs/en/docs/skoala/images/gov00.png)
   
2. Select `Fusing rule`, then click __Create Fusing Rule__ on the right side.

    ![](https://docs.daocloud.io/daocloud-docs-images/docs/en/docs/skoala/images/gov04.png)

3. Fill in the rule configuration based on the instructions below and click __OK__ in the bottom right corner.

    - Resource Name: Specify the resource for which you want to control the traffic, such as a specific API endpoint, function, or variable within the current service.
    - Slow Call Ratio: If the ratio of slow calls within a unit statistical period exceeds the set threshold, the resource will be circuit broken for the remaining time within the circuit breaker's duration.
    - Exception Ratio: If the ratio of exception requests within a unit statistical period exceeds the threshold, the resource will be circuit broken for the remaining time.
    - Exception Count: If the number of exception requests received within a unit statistical period exceeds the set threshold, the resource will be circuit broken for the remaining time.
    - Maximum RT: The maximum response time of a request, in milliseconds. Requests with a response time greater than this value are considered slow calls.
    - Threshold: The ratio of slow calls (for slow call ratio strategy) / exception requests (for exception ratio strategy) to all requests within a statistical period. The threshold range is [0.0, 1.0], representing 0% - 100%.
    - Circuit Duration: The duration of the circuit breaker, in seconds. During this duration, all requests will fail fast.
    - Minimum Request Count: The minimum number of requests required to trigger the circuit breaker within a statistical period. **Even if the circuit-breaking conditions are met, the circuit breaker will not be triggered if the current number of requests within the statistical period is less than this value**.
    - Statistical Period: The length of the statistical time window, in milliseconds. Valid values range from 1 second to 120 minutes.

    ![](https://docs.daocloud.io/daocloud-docs-images/docs/en/docs/skoala/images/gov06.png)

4. After creating the rule, you can view it in the list of circuit breaking rules. Click the more options button on the right side to update or delete the rule.

   ![](https://docs.daocloud.io/daocloud-docs-images/docs/en/docs/skoala/images/gov07.png)