docker 容器上的服务器访问问题

Question

I am trying to build and run docker image from example on this site: https://kubernetes.io/docs/tutorials/hello-minikube/

//server.js
var http = require('http');

var handleRequest = function(request, response) {
   console.log('Received request for URL: ' + request.url);
   response.writeHead(200);
   response.end('Hello World!');
};
var www = http.createServer(handleRequest);
www.listen(8080);


//Dockerfile
FROM node:6.14.2
EXPOSE 8080
COPY server.js .
CMD node server.js

I use commands

docker build -t nsj .
docker run nsj

They run without error but I cannot access the server on localhost:8080.

What is wrong?

Answer 1

Seems like at least two things are wrong:

1. You need to map the port from your docker host
2. You need to bind your server to 0.0.0.0

So, probably these changes (untested):

In your code:

www.listen(8080, "0.0.0.0");

In your docker command:

docker run nsj -p 8080:8080

Note that having EXPOSE 8080 in your Dockerfile does not actually expose anything. It just "marks" this port in the docker engine's metadata and is intended for both documentation (so people reading the Dockerfile know what it does) and for tools that inspect the docker engine.

To quote from the reference :

The EXPOSE instruction does not actually publish the port. It functions as a type of documentation between the person who builds the image and the person who runs the container, about which ports are intended to be published