retry the quick connect startup probe, and exit non-zero when a start fails

Jellyfin.Server/Program.cs

@@ -54,6 +54,13 @@ namespace Jellyfin.Server
         /// </summary>
         public const string LoggingConfigFileSystem = "logging.json";
 
+        /// <summary>
+        /// How long a failed start keeps the setup server answering before the process exits, so an
+        /// install without a supervisor shows the failure instead of spinning. Skipped under an
+        /// orchestrator, where restarting is its job and holding only stretches the crash loop.
+        /// </summary>
+        private static readonly TimeSpan _setupServerHoldAfterFailedStart = TimeSpan.FromMinutes(10);
+
         private static readonly SerilogLoggerFactory _loggerFactory = new SerilogLoggerFactory();
         private static SetupServer? _setupServer;
         private static CoreAppHost? _appHost;
@@ -255,13 +262,14 @@ namespace Jellyfin.Server
             catch (Exception ex)
             {
                 _restartOnShutdown = false;
+                Environment.ExitCode = 1;
                 _logger.LogCritical(ex, "Error while starting server");
                 if (_setupServer!.IsAlive && !configurationCompleted)
                 {
                     _setupServer!.SoftStop();
-                    if (options.StartupMode is null or Configuration.StartupMode.MediaServer)
+                    if (options.StartupMode is null or Configuration.StartupMode.MediaServer && !IsRunningInContainer())
                     {
-                        await Task.Delay(TimeSpan.FromMinutes(10)).ConfigureAwait(false);
+                        await Task.Delay(_setupServerHoldAfterFailedStart).ConfigureAwait(false);
                     }
 
                     await _setupServer!.StopAsync().ConfigureAwait(false);
@@ -285,6 +293,10 @@ namespace Jellyfin.Server
             }
         }
 
+        // Set by every official .NET base image, including the one this server ships in.
+        private static bool IsRunningInContainer()
+            => string.Equals(Environment.GetEnvironmentVariable("DOTNET_RUNNING_IN_CONTAINER"), "true", StringComparison.OrdinalIgnoreCase);
+
         /// <summary>
         /// [Internal]Runs the startup Migrations.
         /// </summary>