Taking our mynginx image, the easiest way to access the server is to port-forward as we execute the docker run command.
Start the container from the last chapter:
docker run -d -p 80:80 mynginx
With the -p flag we have set so that port 80 on localhost is forward to port 80 on the container. Now we should be able to access localhost and see the file we put there earlier as part of the image build.
The -d flag says to run the container in detached mode, effectively in the background so we don't tie it to the current terminal session.
Get the content from the server:
curl localhost/index.html
If you have two containers that need to talk to each other, at first it can seem complicated. The containers run without knowing they're a container, and you can't address your way back to your host machine easily.
To show that it doesn't work:
Start two alpine containers:
docker run -dit --name alpine1 alpine
docker run -dit --name alpine2 alpine
Attach to the first container:
docker attach alpine1
Ping the second container:
ping alpine2
Thankfully there's a construct called a docker network. This allows for simple intercontainer communication, by allowing addressing by container name.
To create a docker network, we can do it with a single command
Create a docker network:
docker network create mynetwork
Start two alpine containers:
docker run -dit --net mynetwork --name alpine3 alpine
docker run -dit --net mynetwork --name alpine4 alpine
Attach to the first container:
docker attach alpine3
Ping the second container:
ping alpine4
You should now see responses from alpine4