Enable custom settings in an agent policy

In certain cases it can be useful to enable custom settings that are not available in Fleet, and that override the default behavior for Elastic Agent. Examples include limiting the amount of CPU consumed by an agent, configuring the agent download timeout, and overriding the default port used for monitoring.

If you need to limit the amount of CPU consumption you can use the agent.limits.go_max_procs configuration option. This parameter limits the number of operating system threads that can be executing Go code simultaneously in each Go process. The agent.limits.go_max_procs option accepts an integer value not less than 0, which is the default value that stands for "all available CPUs".

The agent.limits.go_max_procs limit applies independently to the agent and each underlying Go process that it supervises. For example, if Elastic Agent is configured to supervise two Beats with agent.limits.go_max_procs: 2 in the policy, then the total CPU limit is six, where each of the three processes (one Elastic Agent and two Beats) may execute independently on two CPUs.

This setting is similar to the Beats max_procs setting. For more detail, refer to the GOMAXPROCS function in the Go runtime documentation.

To enable agent.limits.go_max_procs, run a Fleet API request from the Kibana Dev Tools console to override your current Elastic Agent policy and add the go_max_procs parameter. For example, to limit Go processes supervised by Elastic Agent to two operating system threads each, run:

PUT kbn:/api/fleet/agent_policies/<policy-id>
{
  "name": "<policy-name>",
  "namespace": "default",
  "overrides": {
    "agent": {
      "limits": {
        "go_max_procs": 2
      }
    }
  }
}

You can configure the the amount of time that Elastic Agent waits for an upgrade package download to complete. This is useful in the case of a slow or intermittent network connection.

PUT kbn:/api/fleet/agent_policies/<policy-id>
{
  "name": "Test policy",
  "namespace": "default",
  "overrides": {
    "agent": {
      "download": {
        "timeout": "120s"
      }
    }
  }
}

You can override the default port that Elastic Agent uses to send monitoring data. It’s useful to be able to adjust this setting if you have an application running on the machine on which the agent is deployed, and that is using the same port.

PUT kbn:/api/fleet/agent_policies/<policy-id>
{
  "name": "Agent policy 1",
  "namespace": "default",
  "overrides": {
    "agent.monitoring.http.port": 6792
  }
}