nginx-rendertron.conf

server {

 	listen 80;
	listen [::]:80;


    root   /usr/share/nginx/html;
    index  index.html;

    location / {
        try_files $uri @prerender;
    }
 
    location @prerender {
        
        set $prerender 0;
        if ($http_user_agent ~* "googlebot|bingbot|yandex|baiduspider|twitterbot|facebookexternalhit|rogerbot|linkedinbot|embedly|quora link preview|showyoubot|outbrain|pinterest|slackbot|vkShare|W3C_Validator") {
            set $prerender 1;
        }
        if ($args ~ "_escaped_fragment_") {
            set $prerender 1;
        }
        if ($http_user_agent ~ "Prerender") {
            set $prerender 0;
        }
        if ($uri ~* "\.(js|css|xml|less|png|jpg|jpeg|gif|pdf|doc|txt|ico|rss|zip|mp3|rar|exe|wmv|doc|avi|ppt|mpg|mpeg|tif|wav|mov|psd|ai|xls|mp4|m4a|swf|dat|dmg|iso|flv|m4v|torrent|ttf|woff|svg|eot)") {
            set $prerender 0;
        }
         
        resolver kube-dns.kube-system.svc.cluster.local valid=5s;
        
        if ($prerender = 1) {            
            set $prerender "rendertron";
            # rewrite .* /$scheme://$host$request_uri? break;
            proxy_pass http://$prerender.default.svc.cluster.local/render/$scheme://$host$request_uri?wc-inject-shadydom=true;
        }
        if ($prerender = 0) {
            rewrite .* /index.html break;
        }
    }
}

You need change to this resolver for docker:
resolver 127.0.0.11 ipv6=off;