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This topic covers the Standalone Machine Agent. It does not cover the embedded machine agent included with the App Agent for .NET.

The Standalone Machine Agent uses a built-in hardware monitor to report metrics and hardware utilization data. The hardware monitor is a script that writes data to STDOUT of a process. The Machine Agent is always running and reports to the Controller once a minute.

Performance Data Collected by the Standalone Machine Agent

The agent automatically collects the following performance data:

  1. CPU
    1. Busy, Free
  2. Memory
    1. Used, Free, Total
  3. Disk
    1. Network mounted disks (Free, Used, IO Writes/Reads in KB/s and packets)
    2. Local disks (Free, Used, IO Writes/Reads in KB/s and packets)
      You can configure the agent to monitor virtual disks.
  4. Network interfaces
    1. No Loopback
    2. No disabled or unconnected
    3. Incoming KB, KB/s, packets, packets/s
    4. Outgoing KB, KB/s, packets, packets/s

Standalone Machine Agents and the Flow Map

The Standalone Machine Agent monitors a particular machine and not a particular application server. The agent can therefore refer to multiple nodes running on the same machine. A flow map, on the other hand, displays the communication between different nodes during application execution, or the business transaction flow from tier to tier. A Standalone Machine Agent cannot be a part of the flow and therefore is not shown in the flow map.

Standalone Machine Agents and the Server Health Indicator

Metrics monitored by the agent are included in the infrastructure health indicator in the dashboards.

The health indicator is driven by health rule violations in the given time period and health rule violations are configured on hardware metrics collected by the Standalone Machine Agent. Health rules for all possible metrics are not configured out-of-the-box, so you might want to configure additional health rule according to your requirements. For details see Configure Health Rules.

Common Tasks for the Standalone Machine Agent

To access the Machine Agents window

  • In  the upper right menu bar of the controller UI, click Settings -> AppDynamics Agents 

AppDynamics lists all agents for all business applications.

Resetting Standalone Machine Agents

The reset operation purges all existing metrics for an agent and starts gathering them again. It stops the agent and starts it again.

To reset (stop/restart) a machine agent

1. In the Machine Agents window, select a machine agent.

2. Click Reset Selected Machine Agent.

Associate a Standalone Machine Agent with an Application

If no configuration details are provided during installation, or if the node has been moved to another application, then the Standalone Machine Agent will appear in the System -> Agents tab as "not associated with any applications". To have the Machine Agent start sending metrics or executing workflow tasks, manually associate it with an application.

The following message in the agent log (<machine_agent_home>/logs/machine-agent.log) indicates that there is no application associated with the agent:

Received Metric Registration request for a machine id:<NNNNN> that is NOT registered to any nodes yet, sending back null response!

To associate a Standalone Machine Agent with a business application

1. In the AppDynamics Agents window, select an agent.

2. Click Associate with an Application.

To associate multiple Standalone Machine Agents with multiple business applications

If the machine is hosting servers that belong to multiple business applications, you may need multiple Standalone Machine Agents.

If there are nodes belonging to multiple business applications, you can run multiple Standalone Machine Agents each configured to report metrics for a different node, tier, and application.

Background information: You cannot "assign" a single Standalone Machine Agent to multiple business application per se. A Standalone Machine Agent on a specific machine is automatically associated with all nodes running on that machine. A node is associated with a single business application. Therefore an application is associated with the Standalone Machine Agents of its nodes. By default Standalone Machine Agents inherit the application/tier/node names of the App Agents installed on the same hardware.

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