Mersher Service Management

• Service management is mainly used to effectively control and manage a large number of microservices in distributed systems. This guide will show you how to use the service management capabilities provided by mersher.

Before you start

• Walk through mersher-quick-start, mersher-load-balance and have mersher display programs running.

Grayscale release

Configuration

• 1 Change the version number to 1.1.1 and 1.1.2 respectively in conf microservice.yaml of two mersher_calculator instances. Restart the mersher service and you can see that the service version number has changed in servicecenter.

  

• 2 Change weight options in configuration file router.yaml of mersher_webapp. Then restart service.

  routeRule:
    calculator:        #service name
      - precedence: 2    #precedence of route rule
        route:           #route rule list
        - tags:
            version: 1.1.1
          weight: 70     #weight of 20%
        - tags:
            version: 1.1.2
          weight: 30     #weight of 20%
  

Verification

• Click the Submit button repeatedly and you can see that the BMI Instance ID keep changing according to the weight configuration.

Circuit breaker

Configuration

• 1 Change the circuit breaker configuration in conf chassis.yaml of mersher_webapp.

  isolation:
    Consumer:
      timeout:
        enabled: true
      timeoutInMilliseconds: 1000            
      maxConcurrentRequests: 1
  circuitBreaker:
    Consumer:
      enabled: true
      forceOpen: false
      forceClosed: false
      sleepWindowInMilliseconds: 10000    
      requestVolumeThreshold: 1          
      errorThresholdPercentage: 1
  fallback:
    Consumer:
      enabled: true
      maxConcurrentRequests: 1
  fallbackpolicy:
    Consumer:
      policy: returnnull
  

• 2 Stop the service instances in directory test_balance.

Verification

• 1 The circuit breaker of mersher_webapp takes effect when a negative parameter is passed in. The first picture is the log of mersher_webapp. The second picture is the return value when inputing negative parameter. The third picture is the return value when the circuit breaker of mersher_webapp takes effect.

  

  

  

• 2 The service is automatically restored after 10 seconds because of the conf parameter sleepWindowInMilliseconds.

What’s next

• Read mersher distributed tracing

• More about service management