Important: Self-monitoring is intended to help advanced users debug or troubleshoot Hardware Sentry. We recommend using it cautiously, as an incorrect configuration can lead to monitoring issues.

Hardware Sentry can monitor itself, granting you a way to access additional metrics, such as the number of requests for a specific protocol, or the current state of the JVM. Using the OpenTelemetry Java Agent, Hardware Sentry can export traces and metrics of the Hardware Sentry Agent to observe its own performance.

Those traces provide you and Sentry Desk with a complementary way to troubleshoot any problem arising. They describe the internal “path” that the Hardware Sentry application takes to execute its internal tasks and offer a clear overview of what is happening when a problem appears.

Self-Monitoring generates a variety of traces and tracks every protocol request such as:

  • HTTP
  • IPMI
  • OS Command
  • SNMP
  • SSH
  • WBEM
  • WinRM
  • WMI

The metrics range from the number of requests sent for each protocol to the latency measured for each request.

All the JVM metrics have the same attributes: host.arch,, os.description, os.type, pool, process.command_line, process.executable.path,, process.runtime.description,,, process.runtime.version,, service,, telemetry.sdk.language,, telemetry.sdkversion, type, host.

JVM Metrics Description Type Unit
otel.process.runtime.jvm.cpu.utilization Recent CPU utilization for the JVM process Gauge
otel.process.runtime.jvm.system.cpu.utilization Recent CPU utilization for the whole system Gauge
otel.process.runtime.jvm.classes.current_loaded Number of classes currently loaded by the JVM process Gauge
otel.process.runtime.jvm.classes.unloaded Number of classes unloaded by the JVM process since its start Counter
otel.process.runtime.jvm.classes.loaded Number loaded classes by the JVM process since its start Counter
otel.process.runtime.jvm.threads.count JVM process's number of executing threads Gauge
otel.process.runtime.jvm.memory.committed JVM process's memory committed Gauge By
otel.process.runtime.jvm.memory.init JVM process's initial memory requested Gauge By
otel.process.runtime.jvm.memory.limit JVM process's memory size limit Gauge By
otel.process.runtime.jvm.memory.usage JVM process's memory usage Gauge By

Self-monitoring the agent

The Self-Monitoring feature is disabled by default. Follow the steps below to activate it.

Enable OpenTelemetry traces

In order to export the traces to the observability back-end, comment out the traces pipeline inside the otel/otel-config.yaml file and configure the exporter.

  receivers: [otlp]  
  processors: [memory_limiter, batch, resourcedetection]  
  exporters: [logging, datadog/api] # List here the platforms on which you want to see the traces

Configure Java Options

Now that the traces pipeline is configured, you need to add Java options to properly link the OpenTelemetry Java Agent to the Hardware Sentry Agent and configure the service and the exporter.

Warning: you must change the property if you are using multiple Hardware Sentry Agents, so each service has a unique identifier. Otherwise, the observability back-end will aggregate the services together, resulting in issues regarding latency and information loss.

On Windows

Add the following options to the agent.cfg file located in C:\Program Files\hws\app.

java-options=-Dotel.exporter.otlp.headers=Authorization=Basic aHdzOlNlbnRyeVNvZnR3YXJlMSE=

On Linux

Add the following options to the agent.cfg file located in /opt/hws/lib/app.

java-options=-Dotel.exporter.otlp.headers=Authorization=Basic aHdzOlNlbnRyeVNvZnR3YXJlMSE=

Trace example

The traces are made of spans that describe the current state of Hardware Sentry. Every time a request is sent, a span is created. This is what a span looks like:

ScopeSpans #0
 ScopeSpans SchemaURL: 
 InstrumentationScope io.opentelemetry.okhttp-3.0 1.21.0-alpha
 Span #0
     Trace ID       : 1aff7feca80d8ad289fdac5a0e084912
     Parent ID      : 8921469e0196781e
     ID             : 7f4482078c119a15
     Name           : HTTP POST
     Kind           : Client
     Start time     : 2022-12-21 11:38:30.9002252 +0000 UTC
     End time       : 2022-12-21 11:38:31.1696872 +0000 UTC
     Status code    : Unset
     Status message : 
      -> Int(33)
      -> http.url: Str(https://localhost:4317/opentelemetry.proto.collector.metrics.v1.MetricsService/Export)
      -> http.method: Str(POST)
      -> Str(OkHttp https://localhost:4317/...)
      -> Str(localhost)
      -> net.transport: Str(ip_tcp)
      -> net.peer.port: Int(4317)
      -> http.user_agent: Str(OTel OTLP Exporter Java/1.21.0)
      -> http.flavor: Str(2.0)
      -> http.status_code: Int(200)

A span is made of 3 main parts:

  1. ScopeSpans #n1, n1 being the number associated to this group of spans.

  2. Span #n2, n2 being the current span number inside this scope of spans. There are common attributes to every span:

    • Trace ID: Unique ID of the trace.
    • Parent ID: Unique ID of the parent span (empty for root spans).
    • ID: Unique ID of the span.
    • Name: Name of the span, typically describing the step currently tracked by the span.
    • Kind: Type of the span, either Internal for an internal operation within Hardware Sentry or Client for clients automatically supported by the opentelemetry-javaagent such as HttpUrlConnection.
    • Start time: Timestamp marking the beginning of the span's lifecycle.
    • End time: Timestamp marking the end of the span's lifecycle.
    • Status code: Status code of the span, either Unset or Error.
    • Status message: Message associated to the Status code.
  3. Attributes, providing additional information about the current operation being tracked by the span. Attributes are specific to each span. A span tracking an HTTP request will not have the same attributes as a span tracking an SNMP request.

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