MySQL Connection from Docker/Kubernetes with Connection String

xola :

developing an ASP.NET Core 3.0 application, with centralized MySQL Database.

I am using a Connection String, which looks like this:

Server=mysql;Database=db-name;Uid=User;Pwd=Pass;SslMode=Preferred;persistsecurityinfo=false;

"mysql" is an internal DNS Record, which points to the central MySQL Server. In Visual Studio, it works fine.

Now I want to deploy it to kubernetes.

I already did that with MSSQL successfully. I created an endpoint (ep) in kubernetes, pointing to the correct IP:

Name:         mysql
Namespace:    my_namespace
Labels:       <none>
...
Subsets:
  Addresses:          192.168.6.200
  NotReadyAddresses:  <none>
  Ports:
    Name   Port  Protocol
    ----   ----  --------
    mysql  3306  TCP

Events:  <none>

And I created a corresponding Kubernetes service:

Name:              mysql
Namespace:         my_namespace
Labels:            <none>
...
Selector:          <none>
Type:              ClusterIP
IP:                10.104.84.99
Port:              mysql  3306/TCP
TargetPort:        3306/TCP
Endpoints:         192.168.6.200:3306
Session Affinity:  None
Events:            <none>

All this looks like the stuff I did with MSSQL.

And I could confirm the working networking:

root@kubernetes-server:/application# kv exec application-7c85b5d9d8-9vxhb -- curl mysql:3306
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:--  0:00:04 --:--:--     0J
100   115    0   115    0     0     25      0 --:--:--  0:00:04 --:--:--    25#08S01Got packets out of order

"Got packets out of order" is definately a response from the MySQL server. I also could confirm that via Wireshark.

But the application will not run. I get the error: "Unable to connect to any of the specified MySQL hosts."

Did I do something wrong?

Greetings, xola

xola :

Got it. It wasn't the Connection String. Unfortunately, I did't see the errors prior to that error message. Since we encrypt the connection string, we have a key for decryption. The decrypt-key was not correctly set, so the application wanted to set up a connection using the encrypted, not the decrypted Connection String.

But thank you anyway!