Docker nginx / bad gateway : multiple app with docker-compose - docker

Question

sorry for the question. I'm new with docker and nginx. I need some help
So, I have a docker with the nginx proxy and 3 dockers with 3 different applications
I don't know how to configure nginx at all to avoid bad gateway errors on my 3 applications. Can you please help me?
I can only find help for this problem on 1 application.
My docker-compose
version: '2.1'
services:
proxy:
container_name: proxy
hostname: proxy
build: .docker/nginx
ports:
- "80:80" #80:80
- "443:443"
volumes:
- ./certs:/etc/nginx/certs
- /var/run/docker.sock:/tmp/docker.sock:ro
networks:
- proxy
restart: always
networks:
proxy:
external: true
My DockerFile
FROM jwilder/nginx-proxy
RUN { \
echo 'client_max_body_size 500M;'; \
} > /etc/nginx/conf.d/my_proxy.conf
App1
version: '3'
services:
apache:
build: .docker/apache
container_name: app1_apache
environment:
VIRTUAL_HOST: "app1.local"
expose:
- "80"
volumes:
- .docker/config/vhosts:/etc/apache2/sites-enabled
- ../../app1:/var/www/app1.local
depends_on:
- php
networks:
- default
- proxy
php:
build: .docker/php
container_name: app1_php
environment:
VIRTUAL_HOST: "app1.local"
volumes:
- ../../app1:/var/www/app1.local
networks:
- default
- proxy
networks:
proxy:
external: true
Same file for App2 and App3
I found this solution but I don't understand how to implement it.
nginx docker container: 502 bad gateway response
I need to modify the nginx config.d configuration file but I don't see how I can do that.
my default config.d file
server {
listen 80;
server_name localhost;
#charset koi8-r;
#access_log /var/log/nginx/log/host.access.log main;
location / {
root /usr/share/nginx/html;
index index.html index.htm;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
# proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
# root html;
# fastcgi_pass 127.0.0.1:9000;
# fastcgi_index index.php;
# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
# include fastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}
So, I have to add
upstream app1{
//insert your hosts ip here
server 192.168.99.100:8080;
}
upstream app2{
//insert your hosts ip here
server 192.168.99.100:8080;
}
upstream app3{
//insert your hosts ip here
server 192.168.99.100:8080;
}
That's right ?
Do I also have to change the proxy_pass?
The nginx configuration is really obscure to me.
Thank you for your help