Oracle.ManagedAccess.Client in .NET Core application running in Docker Linux Container

3758290

Hello

We are creating a Microservice based architecture with smaller Docker Containers hosting .NET Core 2.0 REST API. The Rest API internally uses Oracle.ManagedAccess.Client and connects to the Oracle Database hosted in Data center and retrieves the result. When the service is tested in Non-Docker mode, the application works and in the Docker Mode, it fails with ORA-12545. The stack trace of the errors are provided herewith:

ExtendedSocketException: No such device or address

System.Net.Dns.InternalGetHostByName(string hostName, bool includeIPv6)

NetworkException: ORA-12545: Network Transport: Unable to resolve connect hostname

OracleInternal.Network.OracleCommunication.DoConnect(string tnsDescriptor)

OracleException: ORA-12545: Network Transport: Unable to resolve connect hostname

The Docker Image is created from the base microsoft optimized image (microsoft/aspnetcore:2.0). What are we doing incorrect? Should we need to do additional configuration in the Docker image to enable the connection?

Christian.Shay -Oracle

Hello,

From your error, dns lookup of the database hostname appears to be failing. I would start by putting the IP address in your connect alias definition or connection string to verify that. Also I would make sure that there is no mistake which connection alias is being used.

If you still have the problem after trying the above, let us know:

1) Version number of ODP.NET Core

2) How exactly you are providing the connection details to ODP.NET... using an alias? Are you using a TNSNAMES.ORA file (and where is the file)? Trying to use configuration APIs?

3) How are you launching docker (what command line arguments are you passing)

Finally, have a google at Docker DNS issues... I'm not really a docker expert:

https://www.google.com/search?q=dns+lookup+fails+on+docker

Christian.Shay -Oracle

Hello,

From your error, dns lookup of the database hostname appears to be failing. I would start by putting the IP address in your connect alias definition or connection string to verify that. Also I would make sure that there is no mistake which connection alias is being used.

If you still have the problem after trying the above, let us know:

1) Version number of ODP.NET Core

2) How exactly you are providing the connection details to ODP.NET... using an alias? Are you using a TNSNAMES.ORA file (and where is the file)? Trying to use configuration APIs?

3) How are you launching docker (what command line arguments are you passing)

Finally, have a google at Docker DNS issues... I'm not really a docker expert:

https://www.google.com/search?q=dns+lookup+fails+on+docker

3758290

Thank you! The Connection string had DNS name, replacing with IP address worked.