Invoke Control

Instance-Level Fault Isolation


In the scenario where some instances fail to be called, the instance-level fault isolation function stops the ServiceComb framework from sending requests to the faulty instance.


This instance-level fault isolation function is integrated into the load balancing function. For configuration of the load balancing policy, see Service Configurations. For parameters associated with instance-level fault isolation in the load balancing policy, see table below:

Configuration Item Default Value Value Range Mandatory Description Remark
servicecomb.loadbalance.isolation.enabled false Boolean No Specifies whether to enable faulty instance isolation. -
servicecomb.loadbalance.isolation.enableRequestThreshold 20 Integer No Specifies the threshold number of instance calls. If this value is reached, isolation is enabled. -
servicecomb.loadbalance.isolation.errorThresholdPercentage 20 Integer, (0,100] No Specifies the error percentage. Instance fault isolation is enabled when the set value is reached. -
servicecomb.loadbalance.isolation.singleTestTime 10000 Integer No Specifies the duration of a faulty instance test on a single node.  

Circuit Break Policy


Circuit brake policy can configure ServiceComb fallback capability, you can configure conditions under which service will stop send request after circuit break policy configured.


Circuit break is part of fallback policy when a service request is abnormal, relevant concept such as isolation and fault tolerance please refer to fallback policy

Flow Control Policy


You can limit the frequency of request send to specific microservice when flow control was enables in consumer service.


See detail info at Service Configurations


Flow control policy configuration is in microservice.yaml file. You need to configure consumer handler in chain of service. See example blow:

        default: qps-flowcontrol-consumer

Configuration items of QPS:

Configuration Item Default Value Value Range Mandatory Description Remark
servicecomb.flowcontrol.Consumer.qps.enabled true Boolean No Specifies whether consumers flowcontrol enables. -
servicecomb.flowcontrol.Consumer.qps.limit.[ServiceName].[Schema].[operation] 2147483647 (max int) (0,2147483647], Integer No Specifies number of requests per second. Support three level configurations: microservice、schema、operation.