Docker container is only able to access MSSQL running inside another container with the internal IP/port

Question

I have deployed a very simple MSSQL docker container using the following docker run command :

docker run -e "ACCEPT_EULA=Y" -e "SA_PASSWORD=NotYourBusiness" -p 2433:1433 --name sql1 -d mcr.microsoft.com/mssql/server:2017-latest

I have SSMS installed on my machine and i'm able to connect to this instance with the following URL :

MyHostName,2433

I am able to run my spring boot app from my machine also with the following connection string :

dataSource.setJdbcUrl("jdbc:sqlserver://localhost:2433;database=SomeDatabase;");

With only MSSQL in a docker container, my application works perfectly from my machine.

Now, i want to put my spring boot app into a container as well. I have therefore built the following docker file :

FROM openjdk:11-jre-slim
VOLUME /tmp
EXPOSE 8082
ADD target/tno-1.0.jar tno-1.0.jar
ENTRYPOINT ["java","-jar","tno-1.0.jar"]

This is the build command i use to create the image :

docker build -f Dockerfile -t tno .

And this is the command i use to build the container :

docker run -t --name tno --link sql1:mssql -p 8082:8082 tno

Using the same connection string that works on my machine, the spring boot app fails to start with a connection refused error. I did look at many posts and they pointed out that the term "localhost" no longer really applies when running from a container since it refers to that container only. The only way i was able to make it work is to replace localhost:2433 with the container IP address : 1433.

This is perfectly acceptable but is there a way for a container to behave like my dev machine and be able to connect to another container as if the connection was coming from the outside world?

Thanks

Answer 1

If you can access to the database from the application running in other containers, try to configure your jdbc url from localhost to mssql (name of db link).

jdbc:sqlserver://mssql:2433;database=SomeDatabase ;

Let me know or check this how to link container in docker?