I a using nginx as a reversproxy for a golang app.

I run the 2 docker containers like this

docker run --rm -t -p 8080:8080 --name goapp helloworld-go
docker run --rm  -p 8000:80 --link goapp:abc.xyz --name nginx-proxy foo/nginx

when I run

docker exec -it nginx-proxy cat /etc/hosts

output is below as you can see 172.17.0.2 is mapped to abc.xyz

127.0.0.1   localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
172.17.0.2  abc.xyz d9000af82a8f goapp
172.17.0.3  ebf96988c18c

nginx default.conf

server {
    listen 80;

    location / {
        try_files $uri @upstream;
    }

    location @upstream{
        proxy_pass http://$proxy_pass;
        
    }
}

nginx map

map $host $proxy_pass {
    hostnames;
    www.mydomain.com                   abc.xyz:8080;
}

but if I put proxy_pass http://abc.xyz:8080 it works. It is able to resolve based on what is in the /etc/hosts of the nginx container.

How to I force nginx to resolve to nginx container’s /etc/hosts. What IP should I put for the resolver directive to that it is force to look at nginx container’s /etc/hosts?