AppDynamics Pro – basics

Adrian Citu

The goal of this ticket is to present and explain the basic notions of the AppDynamics Pro product.

  • Node – a node is the basic unit of processing that AppDynamics monitors. A node is instrumented by an AppDynamics agent.
  • Tier – a tier represents an instrumented service or multiple services that perform the exact same functionality. It represents a more logical view of the application.A tier is composed of one or multiple nodes.
  • Application – multiple tiers gathered together.
  • Business Transaction – represents a distinct logical user activity. The entire application traffic is organized in Business Transactions.
  • Transaction Snapshot -set of diagnostic data, taken at a certain point in time, for a specific Business Transaction across all the tiers though which the transaction has passed. The Transaction Snapshots are triggered periodically (every 10 minutes) or automatically for the slow and error business transactions.
  • Metrics -application performance informations sent from the App Server Agents and Machine Agents to the controller.
  • Baselines – set of metrics within a time range.
  • Baseline Deviations – degree of deviation from baseline at any given point in time and by default are calculated by a number of standard deviations above the average.
  • Service Endpoint – performance metrics focused on a particular service or set of services independent of business transactions.
  • Health Rule – defines a condition or set of conditions in terms of metrics. The condition compares the performance metrics that AppDynamics collects with some static or dynamic threshold that you define. If performance exceeds the threshold, a health rule violation event is triggered. There are two types of thresholds: Warning and Critical.
  • Diagnostic Session – the goal is to collect extra Transaction Snapshots for one or more Business Transactions for a period of time.
  • Events – emitted when the application state change. Eight type of events:
    • Health rules violation
    • Too many slow transactions
    • Too many errors
    • Code problems
    • Application changes
    • JVM and CLR (.NET) Crashes
    • AppDynamics Config Warnings
    • Discovery (new application, tier or done discovered)
  • Errors – AppDynamics treat as errors the following events:
    • unhandled exceptions
    • HTTP error codes from 400 to 505 (the error codes to catch are configurable)
    • Error or Fatal logging events (Log4j or java.util.logging)
  • Information Points – collects metrics outside the context of Business Transactions and across several Business Transactions. For me it looks similar with the Service Endpoints.
  • Data Collectors – collects extra-information at the Business Transaction level like application code arguments, return values, and variables and displays the information in the Call Drill Down panels. There are two types of Data Collectors : method invocation date collectors and HTTP data collectors.