1.2 Validate & Test Configuration

Gateway: In the Gateway terminal window, run the following command to start the Gateway:

../otelcol --config=gateway.yaml

If everything is configured correctly, the collector will start and state Everything is ready. Begin running and processing data. in the output, similar to the following:

2025-06-09T09:22:11.944+0100    info    service@v0.126.0/service.go:289 Everything is ready. Begin running and processing data. {"resource": {}}

Once the Gateway is running, it will listen for incoming data on port 5318 and export the received data to the following files:

• gateway-traces.out
• gateway-metrics.out
• gateway-logs.out

Start the Agent: In the Agent terminal window start the agent with the agent configuration:

../otelcol --config=agent.yaml

Verify CPU Metrics:

1. Check that when the Agent starts, it immediately starts sending CPU metrics.
2. Both the Agent and the Gateway will display this activity in their debug output. The output should resemble the following snippet:

<snip>
NumberDataPoints #31
Data point attributes:
     -> cpu: Str(cpu3)
     -> state: Str(wait)
StartTimestamp: 2025-07-07 16:49:42 +0000 UTC
Timestamp: 2025-07-09 09:36:21.190226459 +0000 UTC
Value: 77.380000
        {"resource": {}, "otelcol.component.id": "debug", "otelcol.component.kind": "exporter", "otelcol.signal": "metrics"}

At this stage, the Agent continues to collect CPU metrics once per hour or upon each restart and sends them to the gateway. The Gateway processes these metrics and exports them to a file named gateway-metrics.out. This file stores the exported metrics as part of the pipeline service.

Verify Data arrived at Gateway: To confirm that CPU metrics, specifically for cpu0, have successfully reached the gateway, we’ll inspect the gateway-metrics.out file using the jq command.

The following command filters and extracts the system.cpu.time metric, focusing on cpu0. It displays the metric’s state (e.g., user, system, idle, interrupt) along with the corresponding values.

Open or create your third terminal window and name it Tests. Run the command below in the Tests terminal to check the system.cpu.time metric:

jq '.resourceMetrics[].scopeMetrics[].metrics[] | select(.name == "system.cpu.time") | .sum.dataPoints[] | select(.attributes[0].value.stringValue == "cpu0") | {cpu: .attributes[0].value.stringValue, state: .attributes[1].value.stringValue, value: .asDouble}' gateway-metrics.out

{
  "cpu": "cpu0",
  "state": "user",
  "value": 123407.02
}
{
  "cpu": "cpu0",
  "state": "system",
  "value": 64866.6
}
{
  "cpu": "cpu0",
  "state": "idle",
  "value": 216427.87
}
{
  "cpu": "cpu0",
  "state": "interrupt",
  "value": 0
}