I want to deploy an ASP.NET application with MongoDB on Kubernetes locally. Currently the application is working fine with the docker-compose.
In the case of Kubernetes YAML file, I have created a StatefulSet for the MongoDB and a Deployment for the ASP.NET app and also, I have created their respected Services and ConfigMap too. I have attached the complete code below.
Even I can see all the data are loaded into the Mongo database when I use the Mongo-Express Deployment. So, I am sure that the MongoDB StatefulSet is working fine. Now the only concern is the .NET App is throwing an exception called "Resource temporarily unavailable".
About the issue: the build is working fine while performing docker-compose up. But in the case of Kubernetes cluster deployment its throwing this exception:
fail:
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware[1]An unhandled exception has occurred while executing the request.
System.TimeoutException: A timeout occured after 30000ms selecting a server using CompositeServerSelector{ Selectors = MongoDB.Driver.MongoClient+AreSessionsSupportedServerSelector, LatencyLimitingServerSelector{ AllowedLatencyRange = 00:00:00.0150000 } }. Client view of cluster state is { ClusterId : "1", ConnectionMode : "Automatic", Type : "Unknown", State : "Disconnected", Servers : [{ ServerId: "{ ClusterId : 1, EndPoint : "Unspecified/mongo:27017" }", EndPoint: "Unspecified/mongo:27017", ReasonChanged: "Heartbeat", State: "Disconnected", ServerVersion: , TopologyVersion: , Type: "Unknown", HeartbeatException: "MongoDB.Driver.MongoConnectionException: An exception occurred while opening a connection to the server.
System.Net.Internals.SocketExceptionFactory+ExtendedSocketException (00000001, 11): Resource temporarily unavailable
at System.Net.Dns.InternalGetHostByName(String hostName)
at System.Net.Dns.ResolveCallback(Object context)
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw(Exception source)
at System.Net.Dns.HostResolutionEndHelper(IAsyncResult asyncResult)
at System.Net.Dns.EndGetHostAddresses(IAsyncResult asyncResult)
at System.Net.Dns.<>c.b__25_1(IAsyncResult asyncResult)
at System.Threading.Tasks.TaskFactory1.FromAsyncCoreLogic(IAsyncResult iar, Func2 endFunction, Action1 endAction, Task1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location where exception was thrown ---
at MongoDB.Driver.Core.Connections.TcpStreamFactory.ResolveEndPointsAsync(EndPoint initial)
at MongoDB.Driver.Core.Connections.TcpStreamFactory.CreateStreamAsync(EndPoint endPoint, CancellationToken cancellationToken)
at MongoDB.Driver.Core.Connections.BinaryConnection.OpenHelperAsync(CancellationToken cancellationToken)
--- End of inner exception stack trace ---
at MongoDB.Driver.Core.Connections.BinaryConnection.OpenHelperAsync(CancellationToken cancellationToken)
at MongoDB.Driver.Core.Servers.ServerMonitor.InitializeConnectionAsync(CancellationToken cancellationToken) at MongoDB.Driver.Core.Servers.ServerMonitor.HeartbeatAsync(CancellationToken cancellationToken)", LastHeartbeatTimestamp: "2022-06-26T16:04:05.7393346Z", LastUpdateTimestamp: "2022-06-26T16:04:05.7393356Z" }] }. at MongoDB.Driver.Core.Clusters.Cluster.ThrowTimeoutException(IServerSelector selector, ClusterDescription description) at MongoDB.Driver.Core.Clusters.Cluster.WaitForDescriptionChangedHelper.HandleCompletedTask(Task completedTask) at MongoDB.Driver.Core.Clusters.Cluster.WaitForDescriptionChanged(IServerSelector selector, ClusterDescription description, Task descriptionChangedTask, TimeSpan timeout, CancellationToken cancellationToken) at MongoDB.Driver.Core.Clusters.Cluster.SelectServer(IServerSelector selector, CancellationToken cancellationToken) at MongoDB.Driver.MongoClient.AreSessionsSupportedAfterServerSelection(CancellationToken cancellationToken) at MongoDB.Driver.MongoClient.AreSessionsSupported(CancellationToken cancellationToken) at MongoDB.Driver.MongoClient.StartImplicitSession(CancellationToken cancellationToken) at MongoDB.Driver.OperationExecutor.StartImplicitSession(CancellationToken cancellationToken) at MongoDB.Driver.MongoCollectionImpl1.UsingImplicitSession[TResult](Func2 func, CancellationToken cancellationToken) at MongoDB.Driver.MongoCollectionImpl1.FindSync[TProjection](FilterDefinition1 filter, FindOptions2 options, CancellationToken cancellationToken) at MongoDB.Driver.FindFluent2.ToCursor(CancellationToken cancellationToken) at MongoDB.Driver.IAsyncCursorSourceExtensions.FirstOrDefault[TDocument](IAsyncCursorSource`1 source, CancellationToken cancellationToken)
Pretty sure you need the change the name of mongo db connectionstring. Check out the DNS for services section: https://kubernetes.io/docs/concepts/services-networking/dns-pod-service/
In your case it would be mongodb-service.default.svc.cluster.local if you've deployed everything into default namespace.