Introduction to the use of Sermant

Sermant is a bytecode enhancement technology based on JavaAgent. It uses JavaAgent to enhance the host application in a non-intrusive way to solve the microservice governance problem of Java applications. The original intention of Sermant is to establish a solution ecosystem for micro-service governance that is non-intrusive to the development state, reduce the difficulty of service governance development and use, and achieve the effect of simplified development and plug-and-play by means of abstract interface, function integration and plugin isolation. This article introduces the components currently included in Sermant and the compilation and packaging of Sermant.

Architecture Introduction

The overall architecture of Sermant includes sermant-agent, Backend, Dynamic Configuration Center, sermant-injector and other components. Among them, sermant-agent is the implementation component of the core bytecode enhancement, and the rest are the supporting components of the Sermant architecture.

sermant-agent

Sermant-agent is the essential core component of Sermant, which contains bytecode enhancements of sermant-agentcore (opens new window), sermant-plugins (opens new window), sermant-common (opens new window). Sermant-agent takes effect when the host application is launched by specifying the sermant-agent.jar' package via the -javaagent argument.

Sermant-agent is based on JavaAgent technology and supports JDK 1.6 and above.

Please refer to the Sermant-agent User Manual for more instructions on how to use sermant-agent.

Backend

The Backend is the Sermant data processing back-end module and the front-end information display module, which mainly includes the reception and display of Sermant heartbeat information.

The Backend is not a required component of the Sermant, but it is highly recommended deploying the Backend for the observability of the Sermant.

Please refer to the Sermant Backend User Manual for more instructions on how to use the Backend.

Dynamic Configuration Center

Dynamic configuration center is a necessary component for Sermant when dynamic config function is enabled. This function allows Sermant to dynamically pull config from config center to achieve a variety of service governance capabilities, such as label routing, flow control, etc. If the Sermant dynamic configuration capability is not enabled, the dynamic configuration center does not need to be deployed.

Sermant dynamic configuration center currently supports two types: the Zookeeper (opens new window) and ServiceComb Kie (opens new window).

Please refer to the Sermant Dynamic Configuration Center User Manual for more instructions on how to use the dynamic configuration center.

Sermant Injector

Sermant provides a quick way to automatically mount Sermant from the host application in a container environment via the Sermant Injector component. Simply add sermant-injection:enabled to the labels in the yaml of the application deployment to enable this functionality.

The Sermant Injector component is not required for Sermant, but it is highly recommended deploying it in a container environment for quick deployment. Currently Sermant Injector supports k8s 1.15 and above.

Please refer to Sermant-injector User Manual for more instructions on how to use sermant-injector.

Package

How to package

The packaging process of Sermant is roughly divided into the following steps:

• agent: Compile or package core function and stable plugins
• release: Publish built artifacts to Maven Central Repository
• test: Compile or package all the modules in Sermant

Execute the following maven command which packages the Sermant project with agent：

mvn clean package -DskipTests -Pagent

After the command is executed, a folder such as sermant-agent-x.x.x and a compressed file such as sermant-agent-x.x.x.tar.gz will be generated in the project directory. The latter is the product package of sermant and the former is the decompressed content of the product package.

Product Directory

sermant-agent-x.x.x directory contains the following content:

• agent: sermant-agent related product
  • config: contains Sermant configuration files
  • core: contains Sermant core framework jars
  • implement: contains Sermant core implementation jars
  • common: contains Sermant common dependencies
  • pluginPackage: contains the extension function plugin package and configuration files
  • sermant-agent.jar: the entrance of Sermant via -javaagent
• server: contains servers of Sermant, such as Backend.