How to configure Varnish and Memcached correctly for SSL?As search engines require all sites must be with SSL
Memcached is a key value pair storage. AFAIK it has nothing to do with SSL. You need to enable it with the PHP or webserver such as NGINX.
As for Varnish - it is quite complicated and confusing to make it work. I'd suggest sticking to Pagespeed and APCu.
What is the best solution for working with wordpress ssl and caching?3-4 k user per day
& http2 on server
Need wordpres + ssl + Http2 + caching
Personally i'd go with NGINX (with Pagespeed) + HHVM (set for PHP 7.1) + MySQL with Memcached server.
Perhaps someone will tell you how to optimize the maximum speed of the site using the solution for the optimal work of wordpress?
We have a guide in our documentation system that explains how to improve the performance of Bitnami WordPress.
You can also configure WordPress to use AWS S3 service to boost the performance of the application.
In case you're looking for a different configuration of WordPress, we suggest you ask in the official forums of the application to get more information about it.