配置Nginx进行路由

Question

I am using Nginx docker image on port 80 in my VM (address xyzw ). So when I try http://xyzw in my browser, it is showing me Nginx index file.

Now I am configuring (basically proxy passing) it for my two docker images running on same VM on ports 8081 and 8082. What I want:

when I type http://x.y.z.w/a it should go to http://x.y.z.w:8081
when I type http://x.y.z.w/b it should go to http://x.y.z.w:8082

For this, I changed a portion in my conf file:

     location /a {
        rewrite ^/a(.*) /$1 break;
        proxy_pass http://x.y.z.w:8081 ;
    }

    location /b {
        rewrite ^/b(.*) /$1 break;
        proxy_pass http://x.y.z.w:8082 ;
    }

It is working as expected. But as all the images are in same machine (have same IP), I want to use localhost instead of xyzw . But it is not working with localhost .

Basically, I don't want to use the hardcoded IP (xyzw) in links, as the IP can change in the future.

Is there any way, Nginx can know the variable IP on which it is running and I may use that IP. Or how can it work with localhost with some modification?

Answer 1

You can't use localhost to address another docker container, since it refers to the loopback of the container and not of the host. As @Tuan suggested, you can link ( https://docs.docker.com/engine/userguide/networking/default_network/dockerlinks/ ) containers, so they can communicate via their names. Eg:

docker run --rm -ti --name backend nginx:latest
docker run --rm -ti --name proxy --link backend:backend nginx:latest

Now proxy knows about backend .

Answer 2

I just replaced every occurrence of xyzw in my nginx.conf with $host and it is working fine.

For example, instead of proxy_pass http://xyzw:8081 ; ,

wrote it proxy_pass http://$host:8081 ;

Now if my IP ( xyzw ) changes, it does not effect to my applications.