SQL Server connection with Docker and Entity Framework

For sharing network between two containers, we could use docker-compose which will create the shared network.

Follow steps below:

1. docker-compose

   version: '3.4'services:coredocker:    image: coredocker    build:    context: .    dockerfile: CoreDocker/Dockerfilesql.data:    image: microsoft/mssql-server-linux:2017-latest    environment:    - SA_PASSWORD=Pass@word    - ACCEPT_EULA=Y    ports:    - "1433:1433"

2. appsettings.json

   {    "ConnectionStrings": {        "DefaultConnection": "Server=sql.data,1433;Database=CoreDocker;MultipleActiveResultSets=true;User ID=sa;Password=Pass@word"    },    "Logging": {        "LogLevel": {        "Default": "Warning"        }    },    "AllowedHosts": "*"}

Here are two points:

1. Change Server=tcp:127.0.0.1,1433; to Server=sql.data,1433 which is the service name and port
2. Remove Trusted_Connection=True;

As this is not clear, I am assuming that both your service and the db are dockerized.

Then first, in the appsettings.json you have to specify the IP-address of the docker host instead of localhost, since localhost only refers to the localhost of the container itself. You might want to read more about docker networking here.

Second, I see no reason to overcomplicate the docker-compose.yml by also specifying an override.yml, but it has to be docker-compose.override.yml instead of docker-compose-override.yml. For debugging it might be helpful to see how a container is really started (especially if using docker-compose) with the help of docker inspect.