essential parts for let's encrypt renewal under nginx

gistfile1.txt

server {
    listen 80;
    # set root and server_name here

    # only serve validation files for Let's Encrypt on port 80
    location /.well-known/acme-challenge/ {
        try_files $uri /dev/null =404;
    }

    # otherwise to SSL
    location / {
        return 301 https://$server_name$request_uri;
    }

}

server {
    listen 443 ssl;
    # set root and server_name here
    # set location of ssl certificates

    # let's encrypt domain validation
    location /.well-known/acme-challenge/ {
        try_files $uri /dev/null =404;
    }

    location / {
        # regular site requests
    }

    # this prevents hidden files (beginning with a period) from being served
    location ~ /\. {
        access_log off;
        log_not_found off;
        deny all;
    }

}