Urgent Installing WordPress on Lemp

Can you clarify what you’re looking to accomplish? Running multiple caching layers will not necessarily improve the performance of your site and could even impact it negatively since each of these caching systems requires resources of their own.

This is a great walk through to get you started.

• https://deliciousbrains.com/hosting-wordpress-setup-secure-virtual-server/

The following guides are not so much a one off walk through but each have a great deal to offer. I suggest reading through them and take what you need/like and adjust your setup/configuration as needed.

Installing the LEMP Stack on Ubuntu:16.04

• https://www.digitalocean.com/community/tutorials/how-to-install-linux-nginx-mysql-php-lemp-stack-in-ubuntu-16-04

Securing NGINX with LetsEncrypt

• https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-16-04

This is my preferred method for NGINX and LetsEncrypt.

• https://gist.github.com/cecilemuller/a26737699a7e70a7093d4dc115915de8

Optimizing NGINX with PHP pools - This guide is for Ubuntu:13.04 and PHP5 however it is still relevant. You will need to adjust for your PHP version.

• https://www.digitalocean.com/community/tutorials/how-to-optimize-nginx-with-php-pools-on-an-ubuntu-13-04-vps

Installing WordPress on Ubuntu:16.04 with NGINX

• https://www.digitalocean.com/community/tutorials/how-to-install-wordpress-with-lemp-on-ubuntu-16-04

Understanding Caching with NGINX/NGINX Plus

• https://www.nginx.com/blog/nginx-caching-guide/

Enable PHP7 Opcache + a discussion on configuring.

• https://lastplaceonthe.net/how-to-enable-php-7-opcache-on-ubuntu-16-04/
• https://www.digitalocean.com/community/questions/configure-tune-opcache-on-php7

Installing Redis on Ubuntu:16.04

• https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-redis-on-ubuntu-16-04

Using Redis with WordPress (I use Method 2 Personally)

• https://www.cloudways.com/blog/install-redis-cache-wordpress/

Hope that helps!

502 means that you have received an invalid response from your backend server. In this case it is most likely PHP. You will need to go through your configs and ensure they are correct.