在k8s中使用OpenTelemetry auto-instru

原文

创建collector

apiVersion: opentelemetry.io/v1alpha1
kind: OpenTelemetryCollector
metadata:
  name: otel
spec:
  config: |
    receivers:
      otlp:
        protocols:
          grpc:
          http:
    processors:

    exporters:
      logging:

    service:
      pipelines:
        traces:
          receivers: [otlp]
          processors: []
          exporters: [logging]

会自动创建configmap,serviceaccount,service, deployment/daemonset/statefulset

service name为crd的name后面加-collector

创建Instrumentation

内容如下

apiVersion: opentelemetry.io/v1alpha1
kind: Instrumentation
metadata:
  name: my-instrumentation
spec:
  exporter:
    endpoint: http://otel-collector:4317
  propagators:
    - tracecontext
    - baggage
    - b3
  sampler:
    type: parentbased_traceidratio
    argument: "0.25"
  java:
    image: ghcr.io/open-telemetry/opentelemetry-operator/autoinstrumentation-java:latest
  nodejs:
    image: ghcr.io/open-telemetry/opentelemetry-operator/autoinstrumentation-nodejs:latest
  python:
    image: ghcr.io/open-telemetry/opentelemetry-operator/autoinstrumentation-python:latest

创建deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: spring-petclinic
spec:
  selector:
    matchLabels:
      app: spring-petclinic
  replicas: 1
  template:
    metadata:
      labels:
        app: spring-petclinic
      annotations:
        sidecar.opentelemetry.io/inject: "true"
        instrumentation.opentelemetry.io/inject-java: "true"
    spec:
      containers:
      - name: app
        image: ghcr.io/pavolloffay/spring-petclinic:latest

自动注入以下环境变量到pod的第一个容器中,用于sdk的相应配置

OTEL_SERVICE_NAME
OTEL_EXPORTER_OTLP_ENDPOINT
OTEL_RESOURCE_ATTRIBUTES
OTEL_PROPAGATORS,OTEL_TRACES_SAMPLER
OTEL_TRACES_SAMPLER_ARG

相关代码

代码仓库github.com/open-telemetry/opentelemetry-operator

main.go中

func main() {
    ...
    mgr.GetWebhookServer().Register("/mutate-v1-pod", &webhook.Admission{
            Handler: webhookhandler.NewWebhookHandler(cfg, ctrl.Log.WithName("pod-webhook"), mgr.GetClient(),
                []webhookhandler.PodMutator{
                    sidecar.NewMutator(logger, cfg, mgr.GetClient()),
                    instrumentation.NewMutator(logger, mgr.GetClient()),
                }),
    })
    ...
}

pkg/instrumentation/podmutator.go中

func NewMutator(logger logr.Logger, client client.Client) *instPodMutator {
    return &instPodMutator{
        Logger: logger,
        Client: client,
        sdkInjector: &sdkInjector{
            logger: logger,
            client: client,
        },
    }
}

func (pm *instPodMutator) Mutate(ctx context.Context, ns corev1.Namespace, pod corev1.Pod) (corev1.Pod, error) {
    ...
    return pm.sdkInjector.inject(ctx, insts, ns, pod), nil
}

pkg/instrumentation/sdk.go中

func (i *sdkInjector) inject(ctx context.Context, insts languageInstrumentations, ns corev1.Namespace, pod corev1.Pod) corev1.Pod {
    ...
    if insts.Java != nil {
        otelinst := *insts.Java
        i.logger.V(1).Info("injecting java instrumentation into pod", "otelinst-namespace", otelinst.Namespace, "otelinst-name", otelinst.Name)
        pod = i.injectCommonSDKConfig(ctx, otelinst, ns, pod)
        pod = injectJavaagent(i.logger, otelinst.Spec.Java, pod)
    }
    ...
    return pod
}

func (i *sdkInjector) injectCommonSDKConfig(ctx context.Context, otelinst v1alpha1.Instrumentation, ns corev1.Namespace, pod corev1.Pod) corev1.Pod {
    container := &pod.Spec.Containers[0]
    resourceMap := i.createResourceMap(ctx, otelinst, ns, pod)
    idx := getIndexOfEnv(container.Env, envOTELServiceName)
    if idx == -1 { 
        container.Env = append(container.Env, corev1.EnvVar{
            Name:  envOTELServiceName,
            Value: chooseServiceName(pod, resourceMap),
        })
    }
    ...
}