I have a Dot Net Core 3.1 Worker Service Project which is hosted on Azure Kubernetes using Linux Docker as a CronJob.

The worker service needs to make external API calls as per the schedule. But when the pod instantiates for execution, I get the Connection refused error.

What is more frustrating is that I have other projects running as Linux Dockers but Dot Net Core 2 API projects and they are able to make external API calls using the same code as shown below.

Below are the codes:

WorkerService:

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            while (!stoppingToken.IsCancellationRequested)
            {
                try
                {
                    await _jobService.SyncProducts();
                }
                catch (Exception ex)
                {
                    _logger.LogInformation($"{ex.Message}, {ex.InnerException}, {ex.StackTrace}");
                }

                Environment.Exit(1);
            }
        }

Startup:

    public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
            .ConfigureServices((hostContext, services) =>
            {
                services.AddHostedService<Worker>();

                services.AddHttpClient(
                    "JobService",
                    client =>
                    {
                        client.BaseAddress = new Uri($"{config.Endpoint}"); // BaseAddress
                    })
                    .AddPolicyHandler(timeoutPolicy)
                    .AddPolicyHandler(request => request.Method == HttpMethod.Get ? retryPolicy : noOpPolicy)
                    .AddPolicyHandler(throttlerPolicy)
                    .SetHandlerLifetime(TimeSpan.FromMinutes(config.HandlerLifeSpanInMinutes));

                services.AddSingleton(typeof(IJobService), typeof(JobService));
            });

Error:

Connection refused, System.Net.Sockets.SocketException (111): Connection refused
     at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken),    at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
     at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
     at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
     at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
     at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
     at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
     at Microsoft.Extensions.Http.Logging.LoggingHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
     at Polly.Bulkhead.AsyncBulkheadEngine.ImplementationAsync[TResult](Func`3 action, Context context, Func`2 onBulkheadRejectedAsync, SemaphoreSlim maxParallelizationSemaphore, SemaphoreSlim maxQueuedActionsSemaphore, CancellationToken cancellationToken, Boolean continueOnCapturedContext)
     at Polly.AsyncPolicy`1.ExecuteAsync(Func`3 action, Context context, CancellationToken cancellationToken, Boolean continueOnCapturedContext)
     at Microsoft.Extensions.Http.PolicyHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
     at Polly.Retry.AsyncRetryEngine.ImplementationAsync[TResult](Func`3 action, Context context, CancellationToken cancellationToken, ExceptionPredicates shouldRetryExceptionPredicates, ResultPredicates`1 shouldRetryResultPredicates, Func`5 onRetryAsync, Int32 permittedRetryCount, IEnumerable`1 sleepDurationsEnumerable, Func`4 sleepDurationProvider, Boolean continueOnCapturedContext)
     at Polly.AsyncPolicy`1.ExecuteAsync(Func`3 action, Context context, CancellationToken cancellationToken, Boolean continueOnCapturedContext)
     at Microsoft.Extensions.Http.PolicyHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
     at Polly.Timeout.AsyncTimeoutEngine.ImplementationAsync[TResult](Func`3 action, Context context, CancellationToken cancellationToken, Func`2 timeoutProvider, TimeoutStrategy timeoutStrategy, Func`5 onTimeoutAsync, Boolean continueOnCapturedContext)
     at Polly.Timeout.AsyncTimeoutEngine.ImplementationAsync[TResult](Func`3 action, Context context, CancellationToken cancellationToken, Func`2 timeoutProvider, TimeoutStrategy timeoutStrategy, Func`5 onTimeoutAsync, Boolean continueOnCapturedContext)
     at Polly.AsyncPolicy`1.ExecuteAsync(Func`3 action, Context context, CancellationToken cancellationToken, Boolean continueOnCapturedContext)
     at Microsoft.Extensions.Http.PolicyHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
     at Microsoft.Extensions.Http.Logging.LoggingScopeHttpMessageHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
     at System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
     at SE.CAF.ETA.Workers.Agena.PIM.Sync.Services.EtaJobService.SyncAgenaProducts(Int32 page) in /src/SE.CAF.ETA.Workers.Agena.PIM.Sync/Services/EtaJobService.cs:line 34
     at SE.CAF.ETA.Workers.Agena.PIM.Sync.Worker.ExecuteAsync(CancellationToken stoppingToken) in /src/SE.CAF.ETA.Workers.Agena.PIM.Sync/Worker.cs:line 38

CronJob Yaml File:

apiVersion: batch/v1beta1
kind: CronJob
metadata:
    name: eta-worker-agena-pim-sync-cron-job
    namespace: eta-core
spec:
  schedule: "*/2 * * * *"
  concurrencyPolicy: Forbid
  jobTemplate:
    spec:
      activeDeadlineSeconds: 600
      template:
        metadata:
          labels:
            app: eta-agena-pim-sync
        spec:
          restartPolicy: OnFailure
          containers:
          - name: eta-agena-pim-sync
            image: etadev.azurecr.io/worker_agena_pim_sync:latest
            imagePullPolicy: Always
            env:
              - name: DOTNET_ENVIRONMENT
                value: dev