Configuration Rules

override rules

Overriding rules is a capability designed by Dubbo to dynamically adjust the behavior of RPC calls without restarting the application. Starting from version 2.7.0, dynamic configuration adjustments are supported at two granularities of service and application.

Overview

Please view or modify override rules in the service governance console.

Application Granularity

# Change the weight of all services (scope:application) provided by the application demo (key:demo) on port 20880 (side:provider) to 1000 (weight:1000).
---
configVersion: v2.7
scope: application
key: demo
enabled: true
configs:
- addresses: ["0.0.0.0:20880"]
  side: provider
  parameters:
  weight: 1000
  ...

Service Granularity

# All consumer (side:consumer) DemoService service (key:org.apache.dubbo.samples.governance.api.DemoService) application instance (addresses:[0.0.0.0]), the timeout is changed to 6000ms
---
configVersion: v2.7
scope: service
key: org.apache.dubbo.samples.governance.api.DemoService
enabled: true
configs:
- addresses: [0.0.0.0]
  side: consumer
  parameters:
  timeout: 6000
  ...

Detailed Rules

Configuration template

---
configVersion: v2.7
scope: application/service
key: app-name/group+service+version
enabled: true
configs:
- addresses: ["0.0.0.0"]
  providerAddresses: ["1.1.1.1:20880", "2.2.2.2:20881"]
  side: consumer
  applications/services: []
  parameters:
    timeout: 1000
    cluster: failfase
    loadbalance: random
- addresses: ["0.0.0.0:20880"]
  side: provider
  applications/services: []
  parameters:
    threadpool: fixed
    threads: 200
    iothreads: 4
    dispatcher: all
    weight: 200
...

in:

• configVersion means dubbo version
• scope indicates the scope of configuration, which is the granularity of application or service. Required.
• key specifies which service or application the rule body acts on. Required.
  • When scope=service, the key value is a combination of [{group}:]{service}[:{version}]
• When scope=application, the key value is the application name
• enabled=true Whether the overriding rule is valid, it can be left blank, and it is valid by default.
• configs defines specific coverage rule content, and n (n>=1) rule bodies can be specified. Required.
  • side,
  • applications
  • services -parameters
  • addresses
  • providerAddresses

For most configuration scenarios, you only need to clarify the following questions to know how to write the configuration:

1. Whether you want to modify the configuration of the entire application or a service.

   • Application: scope: application, key: app-name (you can also use services to specify certain services).
   • Service: scope: service, key:group+service+version.

2. Whether the modification is applied to the consumer or the provider.

   • Consumer: side: consumer, when acting on the consumer side (you can further use providerAddress, applications to select specific provider examples or applications).
   • Provider: side: provider.

3. Whether the configuration takes effect only for certain specific instances.

   • All instances: addresses: ["0.0.0.0"] or addresses: ["0.0.0.0:*"] depends on the side value.
   • Specified instances: addersses[list of instance addresses].

4. Which property is to be modified.

Example

1. Disable provider: (Usually used to temporarily kick off a provider machine, similarly, please use routing rules to prohibit consumer access)

---
configVersion: v2.7
scope: application
key: demo-provider
enabled: true
configs:
- addresses: ["10.20.153.10:20880"]
  side: provider
  parameters:
    disabled: true
...

2. Adjust the weight: (usually used for capacity evaluation, the default weight is 200)

---
configVersion: v2.7
scope: application
key: demo-provider
enabled: true
configs:
- addresses: ["10.20.153.10:20880"]
  side: provider
  parameters:
    weight: 200
...

3. Adjust the load balancing strategy: (the default load balancing strategy is random)

---
configVersion: v2.7
scope: application
key: demo-consumer
enabled: true
configs:
- side: consumer
  parameters:
    loadbalance: random
...

4. Service downgrade: (Usually used to temporarily shield a non-critical service that has an error)

```yaml

configVersion: v2.7 scope: service key: org.apache.dubbo.samples.governance.api.DemoService enabled: true configs:

• side: consumer parameters: force: return null …