server {
    listen 80;
    server_name yyy.xxx.zzz;

    proxy_redirect          off;
    proxy_set_header        Host            $host;
    proxy_set_header        X-Real-IP       $remote_addr;
    proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;

    access_log  /var/log/nginx/YYYYY.access.log  main;

    location / {
        proxy_pass http://clickhouse_cluster1/;
    }

client_max_body_size 20G;
}

    upstream clickhouse_cluster1 {
        server YYYY005.XXXX:8123;
        server YYYY006.XXXX:8123 backup;
    }