Governing Microservices

Prerequisites

• You can create a microservice in Microservice List from Service Catalog and start the microservice. After the microservice starts, the service instance is registered under the corresponding service based on configurations in the .yaml file.
• If the microservice is not created in advance or has been deleted, the microservice is automatically created when the service instance is registered.
• After a microservice is created, register the service instance before performing the corresponding operation.

Governance Policies

You can configure the following policies: Load Balancing, Rate Limiting, Fault Tolerance, Service Degradation, Circuit Breaker, Fault Injection, and Blacklist and Whitelist. For details, see the following table.

Configuring Load Balancing

1. Log in to ServiceStage and choose Cloud Service Engine > Engines.
2. Select the target microservice engine from the Microservice Engine drop-down list in the upper part of the page.
3. Choose Microservice Governance.
   • For microservice engines with security authentication disabled, go to 5.
   • For microservice engines with security authentication enabled, go to 4.

4. In the displayed Security Authentication dialog box, enter the account name and password, and click OK.
   

   • If you connect to the microservice engine for the first time, enter the account name root and the password entered when Creating a Microservice Engine.
   • For details about how to create an account, see Adding an Account.

5. Click the microservice to be governed.
6. Choose Load Balancing.
7. Click New. Select the microservices to be governed and select a proper load balancing policy. For details, see the following table.
   Figure 1 Configuring load balancing (for microservices accessed through Spring Cloud)
   
   Figure 2 Configuring load balancing (for microservices accessed through Java chassis)
   

   Policy	Description
   Round robin	Supports routes according to the location information about service instances.
   Random	Provides random routes for service instances.
   Response time weight	Provides weight routes with the minimum active number (latency) and supports service instances with slow service processing in receiving a small number of requests to prevent the system from stopping response. This load balancing policy is suitable for applications with low and stable service requests. NOTE: This policy applies to microservices accessed through Java chassis.
   Session stickiness	Provides a mechanism on the load balancer. In the specified session stickiness duration, this mechanism allocates the access requests related to the same user to the same instance. Stickiness Duration: time limit for keeping a session. The value ranges from 0 to 86400, in seconds. Failures: number of access failures. The value ranges from 0 to 10. If the upper limit of failures or the session stickiness duration exceeds the specified values, the microservice stops accessing this instance. NOTE: This policy applies to microservices accessed through Java chassis.

8. Click OK.

Configuring Rate Limiting

1. Log in to ServiceStage and choose Cloud Service Engine > Engines.
2. Select the target microservice engine from the Microservice Engine drop-down list in the upper part of the page.
3. Choose Microservice Governance.
   • For microservice engines with security authentication disabled, go to 5.
   • For microservice engines with security authentication enabled, go to 4.

4. In the displayed Security Authentication dialog box, enter the account name and password, and click OK.
   

   • If you connect to the microservice engine for the first time, enter the account name root and the password entered when Creating a Microservice Engine.
   • For details about how to create an account, see Adding an Account.

5. Click the microservice to be governed.
6. Click Rate Limiting.
7. Click New. The following table describes configuration items of rate limiting.
   Figure 3 Configuring rate limiting (for microservices accessed through Spring Cloud)
   
   Figure 4 Configuring rate limiting (for microservices accessed through Java chassis)
   

   Configuration Item	Description	Value Range
   Rate Limiting Object	Other microservices that access the microservice. NOTE: This configuration applies to microservices accessed through Java chassis.	Select an item from the drop-down list next to Rate Limiting Object.
   Upstream Microservice	Configure rate limiting for the upstream microservice to invoke the service. NOTE: This configuration applies to microservices accessed through Spring Cloud.	Select an item from the drop-down list next to Upstream Microservice.
   QPS	Requests generated per second. When the number of requests sent by the rate limiting object to the current service instance exceeds the specified value, the current service instance no longer accepts requests from the rate limiting object.	Enter an integer ranging from 1 to 99999.

   

   If a microservice has three instances, the rate limiting of each instance is set to 2700 QPS, then the total QPS is 8100, and rate limiting is triggered only when the QPS exceeds 8100.

8. Click OK.

Configuring Service Degradation

1. Log in to ServiceStage and choose Cloud Service Engine > Engines.
2. Select the target microservice engine from the Microservice Engine drop-down list in the upper part of the page.
3. Choose Microservice Governance.
   • For microservice engines with security authentication disabled, go to 5.
   • For microservice engines with security authentication enabled, go to 4.

4. In the displayed Security Authentication dialog box, enter the account name and password, and click OK.
   

   • If you connect to the microservice engine for the first time, enter the account name root and the password entered when Creating a Microservice Engine.
   • For details about how to create an account, see Adding an Account.

5. Click the microservice to be governed.
6. Click Service Degradation.
7. Click New and select a proper policy. The following table describes the configuration items of service degradation.
   Figure 5 Configuring service degradation (for microservices accessed through Spring Cloud)
   
   Figure 6 Configuring service degradation (for microservices accessed through Java chassis)
   

   Configuration Item	Description
   Fallback Object	Microservice to be degraded.
   Request Path	Click and set Method, Path, and Headers to specify the request path. NOTE: This configuration applies to microservices accessed through Spring Cloud.
   Fallback	Open Close

8. Click OK.

Configuring Fault Tolerance

1. Log in to ServiceStage and choose Cloud Service Engine > Engines.
2. Select the target microservice engine from the Microservice Engine drop-down list in the upper part of the page.
3. Choose Microservice Governance.
   • For microservice engines with security authentication disabled, go to 5.
   • For microservice engines with security authentication enabled, go to 4.

4. In the displayed Security Authentication dialog box, enter the account name and password, and click OK.
   

   • If you connect to the microservice engine for the first time, enter the account name root and the password entered when Creating a Microservice Engine.
   • For details about how to create an account, see Adding an Account.

5. Click the microservice to be governed.
6. Click Fault Tolerance.
7. Click New and select a proper policy. The following table describes the configuration items of fault tolerance.
   Figure 7 Configuring fault tolerance (for microservices accessed through Spring Cloud)
   
   Figure 8 Configuring fault tolerance (for microservices accessed through Java chassis)
   

   Configuration Item	Description
   Downstream Microservice	Configure fault tolerance for the microservice to invoke the downstream microservice. You can select a value from the drop-down list. NOTE: This configuration applies to microservices accessed through Spring Cloud.
   Fault Tolerance Object	Microservice or method that the application relies on. NOTE: This configuration applies to microservices accessed through Java chassis.
   Fault Tolerance	Open: The system processes a request sent to the fault tolerance object based on the selected fault tolerance policy when the request encounters an error. Close: The system waits until the timeout interval expires and then returns the failure result even though the service request fails to be implemented.
   FT Policy	This parameter is mandatory when Fault Tolerance is set to Open. For microservices accessed through Spring Cloud, set the following parameters: Number of attempts to the same microservice instance Number of attempts to the new microservice instance For microservices accessed through Java chassis, set the following parameters: Failover The system attempts to reestablish connections on different servers. Failfast The system does not attempt to reestablish a connection. After a request fails, a failure result is returned immediately. Failback The system attempts to reestablish connections on the same server. custom Number of attempts to reestablish connections on the same server Number of attempts to reestablish connections on new servers

8. Click OK.

Configuring Circuit Breaker

1. Log in to ServiceStage and choose Cloud Service Engine > Engines.
2. Select the target microservice engine from the Microservice Engine drop-down list in the upper part of the page.
3. Choose Microservice Governance.
   • For microservice engines with security authentication disabled, go to 5.
   • For microservice engines with security authentication enabled, go to 4.

4. In the displayed Security Authentication dialog box, enter the account name and password, and click OK.
   

   • If you connect to the microservice engine for the first time, enter the account name root and the password entered when Creating a Microservice Engine.
   • For details about how to create an account, see Adding an Account.

5. Click the microservice to be governed.
6. Click Circuit Breaker.
7. Click New and select a proper policy. The following table describes the configuration items of circuit breaker.
   Figure 9 Configuring circuit breaker (for microservices accessed through Spring Cloud)
   
   Figure 10 Configuring circuit breaker (for microservices accessed through Java chassis)
   

   Configuration Item	Description
   Downstream Microservice	Configure circuit breaker for the microservice to invoke the downstream microservice. NOTE: This configuration applies to microservices accessed through Spring Cloud.
   Circuit Breaker Object	Microservice or method invoked by the application. NOTE: This configuration applies to microservices accessed through Java chassis.
   Request Path	Click and set Method, Path, and Headers to specify the request path. NOTE: This configuration applies to microservices accessed through Spring Cloud.
   Triggering Condition	Circuit Breaker Time Window: circuit breaker duration. The system does not respond to requests within this time window. Request Failure Rate: failure rate of window requests. Window Requests: number of requests received by the window. Circuit breaker is triggered only when Request Failure Rate and Window Requests both reach their thresholds.

8. Click OK.

Configuring Fault Injection

1. Log in to ServiceStage and choose Cloud Service Engine > Engines.
2. Select the target microservice engine from the Microservice Engine drop-down list in the upper part of the page.
3. Choose Microservice Governance.
   • For microservice engines with security authentication disabled, go to 5.
   • For microservice engines with security authentication enabled, go to 4.

4. In the displayed Security Authentication dialog box, enter the account name and password, and click OK.
   

   • If you connect to the microservice engine for the first time, enter the account name root and the password entered when Creating a Microservice Engine.
   • For details about how to create an account, see Adding an Account.

5. Click the microservice to be governed.
6. Click Fault Injection.
7. Click New and select a proper policy. The following table describes the configuration items of fault injection.
   Figure 11 Configuring fault injection (delayed)
   
   Figure 12 Configuring fault injection (fault)
   

   Configuration Item	Description
   Injection Object	Microservices for which fault injection is required. You can specify a method for this configuration item.
   Type	Type of the fault injected to the microservice. Delayed Fault
   Protocol	Protocol for accessing the microservice when latency or fault occurs. Rest Highway
   Occurrence Probability	Probability of latency or fault occurrence.
   Delay Time	Duration of the latency during microservice access. This parameter is required when Type is set to Delayed.
   HTTP Error Code	HTTP error code during microservice access. This parameter is required when Type is set to Fault. This error code is an HTTP error code.

8. Click OK.

Configuring Blacklist and Whitelist

Based on the public key authentication mechanism, microservice engines provide the blacklist and whitelist functions. The blacklist and whitelist can be used to control which services can be accessed by microservices.

The blacklist and whitelist take effect only after public key authentication is enabled. For details, see Configuring Public Key Authentication.

1. Log in to ServiceStage and choose Cloud Service Engine > Engines.
2. Select the target microservice engine from the Microservice Engine drop-down list in the upper part of the page.
3. Choose Microservice Governance.
   • For microservice engines with security authentication disabled, go to 5.
   • For microservice engines with security authentication enabled, go to 4.

4. In the displayed Security Authentication dialog box, enter the account name and password, and click OK.
   

   • If you connect to the microservice engine for the first time, enter the account name root and the password entered when Creating a Microservice Engine.
   • For details about how to create an account, see Adding an Account.

5. Click the microservice to be governed.
6. Click Black and white list.
7. Click New to add a blacklist or whitelist for the application. The following table describes configuration items of blacklist and whitelist.
   Figure 13 Configuring blacklist and whitelist
   

   Configuration Item	Description
   Type	Blacklist: Microservices that match the matching rule are not allowed to access the current service. Whitelist: Microservices that match the matching rule are allowed to access the current service.
   Rule	Use a regular expression. For example, if Rule is set to data*, services whose names start with data in the blacklist are not allowed to access the current service, or services whose names start with data in the whitelist are allowed to access the current service.

8. Click OK.

Configuring Public Key Authentication

Public key authentication is a simple and efficient authentication mechanism between microservices provided by CSE. Its security is based on the reliable interaction between microservices and the service center. That is, the authentication mechanism must be enabled between microservices and the service center. The procedure is as follows:

1. When the microservice starts, a key pair is generated and the public key is registered with the service center.
2. Before accessing the provider, the consumer uses its own private key to sign a message.
3. The provider obtains the public key of the consumer from the service center and verifies the signed message.

To enable public key authentication, perform the following steps:

1. Enable public key authentication for both the consumer and provider.

   servicecomb:
     handler:
       chain:
         Consumer:
           default: auth-consumer
         Provider:
           default: auth-provider

2. Add the following dependency to the pom.xml file:

   <dependency> 
       <groupId>org.apache.servicecomb</groupId> 
       <artifactId>handler-publickey-auth</artifactId> 
     </dependency>