You can enable caching for your site by changing the cache settings under each site key. Using caching provide substantial speed improvement once the page are cached. The full settings looks like this:
cache: enabled: false duration: 30s skip_cache_uri: /wp-admin/|/xmlrpc.php|wp-.*.php|/feed/|index.php|sitemap(_index)?.xml skip_cache_cookie: comment_author|wordpress_[a-f0-9]+|wp-postpass|wordpress_no_cache|wordpress_logged_in
duration parameter control how long your pages will stay in the cache. You should generally keep this value low, unless your content doesn't change frequently. Lowering the duration to 1s will make the cache more like a DDOS protection, meaning that if you have a sudden spike of traffic, only one request will hit the back-end per second instead of the full load. The whole setup is "micro-cache" oriented, so there is no means of flushing the cache.
skip_cache_uri is a regex that will be used to tell Nginx to not cache pages matching it. Use it if you have sections of your site that you don't want cached (like shopping carts). Override
group_vars/all/main.yml or the specific environment. The default value is shown above.
skip_cache_cookie is a regex that will disable the cache when a cookie match it. Useful for disabling the cache for certain users.
Already cached content will continue be served if your back-end (PHP-FPM / HHVM) go down.