Why is APM Server a separate component?

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The APM Server is a separate component for the following reasons:

  • It helps to keep the agents as light as possible and since the APM Server is a stateless separate component, it can be scaled independently.
  • For Real User monitoring data is collected in browsers. APM Server prevents browsers from interacting directly with Elasticsearch (which poses a security risk), and controls the amount of data flowing into Elasticsearch.
  • In cases where Elasticsearch becomes unresponsive, APM Server can buffer data temporarily without adding overhead to the agents.
  • Acts as a middleware for source mapping for javascript in the browser.
  • Provides a JSON API for agents to use thereby improving compatibility across different versions of agents and the Elastic Stack.