Trouble running opentelemety-collector in a container

[alex-g-axion]

I am trying to get an ASP.NET Core application to send logs to opentelemetry-collection by following the examples from https://opentelemetry.io/docs/languages/dotnet/exporters/

Here is my C# program:

// Copyright The OpenTelemetry Authors
// SPDX-License-Identifier: Apache-2.0

using OpenTelemetry;
using OpenTelemetry.Exporter;
using OpenTelemetry.Logs;
using OpenTelemetry.Metrics;
using OpenTelemetry.Resources;
using OpenTelemetry.Trace;

const string serviceName = "Grocery.Price.Example";

var builder = WebApplication.CreateBuilder(args);

builder.Logging.ClearProviders();

builder.Logging.AddOpenTelemetry(logging =>
{
    logging
        .SetResourceBuilder(
            ResourceBuilder.CreateDefault()
                .AddService(serviceName))
        .AddOtlpExporter(options =>
        {
            options.Endpoint = new Uri("http://localhost:4318/v1/logs");
            options.Protocol = OtlpExportProtocol.HttpProtobuf;
        });
});

// Add OpenTelemetry logging provider by calling the WithLogging extension.
builder.Services.AddOpenTelemetry()
    .ConfigureResource(resource => resource.AddService(serviceName))
    .WithTracing(tracing => tracing
        // The rest of your setup code goes here
        .AddOtlpExporter(options =>
        {
            options.Endpoint = new Uri("http://localhost:4318/v1/traces");
            options.Protocol = OtlpExportProtocol.HttpProtobuf;
        }))
    .WithMetrics(metrics => metrics
        // The rest of your setup code goes here
        .AddOtlpExporter(options =>
        {
            options.Endpoint = new Uri("http://localhost:4318/v1/metrics");
            options.Protocol = OtlpExportProtocol.HttpProtobuf;
        }));

var app = builder.Build();

app.MapGet("/", (ILogger<Program> logger) =>
{
    logger.FoodPriceChanged("artichoke", 9.99);

    return "Hello from OpenTelemetry Logs!";
});

app.Logger.StartingApp();

app.Run();

internal static partial class LoggerExtensions
{
    [LoggerMessage(LogLevel.Information, "Starting the app...")]
    public static partial void StartingApp(this ILogger logger);

    [LoggerMessage(LogLevel.Information, "Food `{name}` price changed to `{price}`.")]
    public static partial void FoodPriceChanged(this ILogger logger, string name, double price);
}

It is based on a sample from https://github.com/open-telemetry/opentelemetry-dotnet

My collector-config.yaml (from https://opentelemetry.io/docs/collector/configuration/#exporters):

receivers:
  otlp:
    protocols:
      grpc:
        endpoint: 0.0.0.0:4317
      http:
        endpoint: 0.0.0.0:4318

exporters:
  debug:
  
extensions:
  zpages:
    endpoint: 0.0.0.0:55679
    
service:
  extensions: [zpages] 
  pipelines:
    traces:
      receivers: [otlp]
      exporters: [debug]
    metrics:
      receivers: [otlp]
      exporters: [debug]
    logs:
      receivers: [otlp]
      exporters: [debug]

I use this command to start the collector:

 podman run -p 4317:4317 -p 4318:4318 -p 55679:55679 -v "C:/dev/OpenTelemetry/collector-config.yaml:/etc/otelcol/config.yaml:z"  otel/opentelemetry-collector:0.143.0

The program runs, but nothing is being communicated to the collector. Further debugging has shown that the issue is that HTTP requests are timing out.

On my Application (OTel SDK) side the log is filled with messages like this:

2026-01-09T16:33:39.3357699Z:Unknown error in TrySubmitRequest method. Message: 'System.Threading.Tasks.TaskCanceledException: The request was canceled due to the configured HttpClient.Timeout of 10 seconds elapsing.
 ---> System.TimeoutException: A task was canceled.
 ---> System.Threading.Tasks.TaskCanceledException: A task was canceled.
   at System.Threading.Tasks.TaskCompletionSourceWithCancellation`1.WaitWithCancellation(CancellationToken cancellationToken)
   at System.Threading.Tasks.TaskCompletionSourceWithCancellation`1.WaitWithCancellationAsync(Boolean async, CancellationToken cancellationToken)
   at System.Net.Http.HttpConnectionWaiter`1.WaitForConnectionWithTelemetryAsync(HttpRequestMessage request, HttpConnectionPool pool, Boolean async, CancellationToken requestCancellationToken)
   at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
   at System.Net.Http.HttpMessageHandlerStage.Send(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.Metrics.MetricsHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
   at System.Net.Http.HttpMessageHandlerStage.Send(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.DiagnosticsHandler.SendAsyncCore(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
   at System.Net.Http.HttpMessageHandlerStage.Send(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.SocketsHttpHandler.Send(HttpRequestMessage request, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.Send(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationToken cancellationToken)
   --- End of inner exception stack trace ---
   --- End of inner exception stack trace ---
   at System.Net.Http.HttpClient.HandleFailure(Exception e, Boolean telemetryStarted, HttpResponseMessage response, CancellationTokenSource cts, CancellationToken cancellationToken, CancellationTokenSource pendingRequestsCts)
   at System.Net.Http.HttpClient.Send(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationToken cancellationToken)
   at OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation.ExportClient.OtlpExportClient.SendHttpRequest(HttpRequestMessage request, CancellationToken cancellationToken)
   at OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation.ExportClient.OtlpHttpExportClient.SendExportRequest(Byte[] buffer, Int32 contentLength, DateTime deadlineUtc, CancellationToken cancellationToken)
   at OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation.Transmission.OtlpExporterTransmissionHandler.TrySubmitRequest(Byte[] request, Int32 contentLength)'

When I try to run a test command it takes a long time:

❯ Measure-Command {
∙ Invoke-WebRequest -Uri "http://localhost:4318/v1/traces" -Method POST -InFile .\traces-2.pb -ContentType "application/x-protobuf"
∙ }


Days              : 0
Hours             : 0
Minutes           : 0
Seconds           : 21
Milliseconds      : 113
Ticks             : 211137801
TotalDays         : 0.000244372454861111
TotalHours        : 0.00586493891666667
TotalMinutes      : 0.351896335
TotalSeconds      : 21.1137801
TotalMilliseconds : 21113.7801

Here it took 21 seconds for the command to work.

zPages (http://localhost:55679/debug/tracez) don't show any posts that take so long. No errors are shown in the logs either.

Here are the two 21-second posts:

2026/01/09-17:27:59.578242      .  4513 trace_id: b84d4e7fb07ed854cb7d8c9612efa8b1 span_id: ff05a677e4e61b2d
                                        Status{Code=Unset, description=""}
                                        Attributes:{client.address=10.88.0.1, http.request.body.size=726, http.request.method=POST, http.response.body.size=2, http.response.status_code=200, network.peer.address=10.88.0.1, network.peer.port=60494, network.protocol.version=1.1, server.address=localhost, server.port=4318, url.path=/v1/traces, url.scheme=http, user_agent.original=Mozilla/5.0 (Windows NT; Windows NT 10.0; en-US) WindowsPowerShell/5.1.26100.7462}
2026/01/09-17:40:47.218836      .  1208 trace_id: b43e0966588de324a8c4318984687200 span_id: 2f87b26666193513
                                        Status{Code=Unset, description=""}
                                        Attributes:{client.address=10.88.0.1, http.request.body.size=726, http.request.method=POST, http.response.body.size=2, http.response.status_code=200, network.peer.address=10.88.0.1, network.peer.port=60659, network.protocol.version=1.1, server.address=localhost, server.port=4318, url.path=/v1/traces, url.scheme=http, user_agent.original=Mozilla/5.0 (Windows NT; Windows NT 10.0; en-US) WindowsPowerShell/5.1.26100.7462}

They always take just over 21 seconds so it seems like there is some kind of an internal timeout in opentelemetry-collector.

What could be the issue?