CODEWITHSUNDEEP
c#asp.net-corekubernetes
kafka
kafka

Reputation: 733

C# application not able to reach a kubernetes service?

I seem to have an issue with my C# applications that I containerize and put into pod, cant seem to reach services withing the cluster?

I made a simple code example 

using System;
using System.Net.NetworkInformation;

namespace pingMe
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            Ping ping = new Ping();
            PingReply pingresult = ping.Send("example-service.default.svc");
            if (pingresult.Status.ToString() == "Success")
            {
                Console.WriteLine("I can reach");
            }
        }
    }
}

which should be able to ping this within the cluster 

PS C:\Helm> kubectl apply -f https://k8s.io/examples/service/access/hello-application.yaml
deployment.apps/hello-world created
PS C:\Helm> kubectl expose deployment hello-world --type=ClusterIP --name=example-service
service/example-service exposed
PS C:\Helm> kubectl get service/example-service
NAME              TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
example-service   ClusterIP   10.97.171.216   <none>        8080/TCP   14s
PS C:\Helm> kubectl get deployment.apps/hello-world
NAME          READY   UP-TO-DATE   AVAILABLE   AGE
hello-world   2/2     2            2           61s

but In the cluster I get this: 

Hello World!
Unhandled exception. System.Net.NetworkInformation.PingException: An exception occurred during a Ping request.
 ---> System.Net.Internals.SocketExceptionFactory+ExtendedSocketException (00000005, 0xFFFDFFFF): Name or service not known
   at System.Net.Dns.InternalGetHostByName(String hostName)
   at System.Net.Dns.GetHostAddresses(String hostNameOrAddress)
   at System.Net.NetworkInformation.Ping.GetAddressAndSend(String hostNameOrAddress, Int32 timeout, Byte[] buffer, PingOptions options)
   --- End of inner exception stack trace ---
   at System.Net.NetworkInformation.Ping.GetAddressAndSend(String hostNameOrAddress, Int32 timeout, Byte[] buffer, PingOptions options)
   at System.Net.NetworkInformation.Ping.Send(String hostNameOrAddress, Int32 timeout, Byte[] buffer, PingOptions options)
   at System.Net.NetworkInformation.Ping.Send(String hostNameOrAddress)
   at pingMe.Program.Main(String[] args) in /src/pingMe/Program.cs:line 12

How come... Adding the port number does not help..

Upvotes: 2

Views: 934

Answers (1)

TwoTabbys
TwoTabbys

Reputation: 81

On the surface it all looks OK. I would start debugging by eliminating possibilities. From the "worker" pod can you ping the ClusterIP and not the service name? Can you successfully do a DNS lookup on any service or pod? If you can access the Cluster IP, but pinging or resolving the service name continues to fail then DNS seems more suspect.

Upvotes: 1

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