cc59ae4d98
OpenTelemetry's Tracer#Start() returns (ctx, span). We have no reasons to swap them. Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>
85 lines
2.5 KiB
Markdown
85 lines
2.5 KiB
Markdown
# Tracing
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containerd supports OpenTelemetry tracing since v1.6.0.
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Tracing currently targets only gRPC calls.
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## Sending traces from containerd deamon
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By configuring `io.containerd.tracing.processor.v1.otlp` plugin.
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containerd daemon can send traces to the specified OpenTelemetry endpoint.
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```toml
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[plugins."io.containerd.tracing.processor.v1.otlp"]
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endpoint = "http://localhost:4318"
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```
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The following options are supported.
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- `endpoint`: The address of a server that receives [OpenTelemetry Protocol](https://github.com/open-telemetry/opentelemetry-specification/blob/v1.8.0/specification/protocol/otlp.md).
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- `protocol`: OpenTelemetry supports multiple protocols.
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The default value is "http/protobuf". "grpc" is also supported.
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- `insecure`: Disable transport security when the protocol is "grpc". The default is false.
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"http/protobuf" always uses the schema provided by the endpoint and
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the value of this setting being ignored.
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The sampling ratio and the service name on the traces could be configured by
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`io.containerd.internal.v1.tracing` plugin.
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```toml
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[plugins."io.containerd.internal.v1.tracing"]
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sampling_ratio = 1.0
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service_name = "containerd"
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```
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## Sending traces from containerd client
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By configuring its underlying gRPC client, containerd's Go client can send
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traces to an OpenTelemetry endpoint.
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Note that the Go client's methods and gRPC calls are not 1:1. Single method
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call would issue multiple gRPC calls.
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```go
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func clientWithTrace() error {
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exp, err := otlptracehttp.New(ctx,
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otlptracehttp.WithEndpoint("localhost:4318"),
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otlptracehttp.WithInsecure(),
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)
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if err != nil {
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return err
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}
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res, err := resource.New(ctx, resource.WithAttributes(
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semconv.ServiceNameKey.String("CLIENT NAME"),
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))
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if err != nil {
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return err
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}
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provider := trace.NewTracerProvider(
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trace.WithSampler(trace.AlwaysSample()),
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trace.WithSpanProcessor(trace.NewSimpleSpanProcessor(exp)),
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trace.WithResource(res),
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)
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otel.SetTracerProvider(provider)
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otel.SetTextMapPropagator(propagation.TraceContext{})
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...
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dialOpts := []grpc.DialOption{
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grpc.WithTransportCredentials(insecure.NewCredentials()),
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grpc.WithStreamInterceptor(otelgrpc.StreamClientInterceptor()),
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grpc.WithUnaryInterceptor(otelgrpc.UnaryClientInterceptor()),
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}
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client, ctx, cancel, err := commands.NewClient(context, containerd.WithDialOpts(dialOpts))
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if err != nil {
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return err
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}
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defer cancel()
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ctx, span := tracing.StartSpan(ctx, "OPERATION NAME")
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defer span.End()
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...
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}
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```
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