无Sidecar时OpenTelemetry自动插装失效及Sidecar开销咨询

背景 #

我们是一家创业公司，近期已将工作负载迁移至AWS EKS集群，正搭建可观测性栈：Signoz部署在单独EC2实例（测试用，集群小型节点无法运行其Helm Chart）；集群已部署OpenTelemetry Operator，且Deployment模式的Collector已验证可正常连接Signoz实例。但尝试为应用实现自动插装时，无Sidecar的方案无法正常工作。

无Sidecar模式的相关配置 #

apiVersion: v1
kind: Namespace
metadata:
  name: opentelemetry
  labels:
    name: opentelemetry
---
apiVersion: opentelemetry.io/v1alpha1
kind: OpenTelemetryCollector
metadata:
  name: otel-collector
  namespace: opentelemetry
spec:
  config: |
    receivers:
      otlp:
        protocols:
          grpc: 
          http:
    processors:
      memory_limiter:
        check_interval: 1s
        limit_percentage: 75
        spike_limit_percentage: 15
      batch:
        send_batch_size: 10000
        timeout: 10s
    exporters:
      otlp:
        endpoint: obs.stg.company.domain:4317
        tls:
          insecure: true
      logging:
    service:
      pipelines:
        traces:
          receivers: [otlp]
          processors: [memory_limiter, batch]
          exporters: [otlp, logging]
        metrics:
          receivers: [otlp]
          processors: [memory_limiter, batch]
          exporters: [otlp, logging]
        logs:
          receivers: [otlp]
          processors: []
          exporters: [otlp, logging]
---
apiVersion: opentelemetry.io/v1alpha1
kind: Instrumentation
metadata:
  name: my-instrumentation
  namespace: opentelemetry
spec:
  exporter:
    endpoint: http://otel-collector-collector.opentelemetry.svc.cluster.local:4317
  propagators: 
    - tracecontext
    - baggage
    - b3
  sampler:
    type: parentbased_traceidratio
    argument: "0.25"
  dotnet:
  nodejs:

无Sidecar模式的现象 #

为应用Deployment或命名空间添加注解instrumentation.opentelemetry.io/inject-dotnet=opentelemetry/auto-instrumentation并重建Pod后，.NET自动插装的init容器运行正常，但Collector和Signoz中均无链路追踪、指标或日志数据。

Sidecar模式的正常配置 #

当创建Sidecar模式的Collector，并将Instrumentation指向该Collector，同时为命名空间添加注解sidecar.opentelemetry.io/inject=sidecar后，可观测数据正常流入Signoz。Sidecar Collector配置如下：

apiVersion: opentelemetry.io/v1alpha1
kind: OpenTelemetryCollector
metadata:
  name: sidecar
  namespace: application
spec:
  mode: sidecar
  config: |
    receivers:
      otlp:
        protocols:
          grpc:
          http:
    processors:
      batch:
    exporters:
      logging:
      otlp:
        endpoint: "http://otel-collector-collector.opentelemetry.svc.cluster.local:4317"
        tls:
          insecure: true
    service:
      telemetry:
        logs:
          level: "debug"
      pipelines:
        traces:
          receivers: [otlp]
          processors: []
          exporters: [logging, otlp]

核心疑问 #

• 集群规模较小，想尽量降低开销：Sidecar方案的开销是否值得担忧？和无Sidecar方案的开销差异是否显著？
• 无Sidecar模式的配置存在哪些问题？已参照Signoz文档配置，但无法获取数据。

内容的提问来源于stack exchange，提问作者Victor Chacon