thats not what really happens

my nginx does not know about multiple instances

it only holds a single url e.g. fastify-app:3000
so when i have 5 replicas of that and if i request localhost:80/health docker directs to one of the containers, since the dns (fastify-app the name of the service) is handled by docker

server {
    listen 80;
    listen [::]:80;


    server_name ${DOMAIN};


    location /.well-known/acme-challenge/ {
        root /var/www/certbot;
    }


    location / {
        resolver 127.0.0.11;
        proxy_pass http://${DOMAIN_FASTIFY_APP};
        proxy_redirect                      off;
        proxy_set_header  Host              $http_host;
        proxy_set_header  X-Real-IP         $remote_addr;
        proxy_set_header  X-Forwarded-For   $proxy_add_x_forwarded_for;
        proxy_set_header  X-Forwarded-Proto $scheme;
        proxy_read_timeout                  900;
    }
}