Load balancing in the cloud still less understood by the end users. Load balancing in practical usage has been explained in this guide. In the article on Making WordPress Scalable, we have discussed the practical usage of Load Balancers. Other theoretical articles like, Principles of Load Balancing, Scalability, and Redundancy, Load Balancer Service from Rackspace and practical guide like How To Configure To Speed Up Your Blog are useful good read for any level of users.
You can add nodes / servers from different service providers like that from DigitalOcean to have more scalability.
Load Balancing in the Cloud : Tips and Tricks
We are taking OpenStack Cloud Software based Load Balancer as a Service as today’s usable service at lower cost. We are not discussing about dedicated Load Balancer which might cost several times more than Load Balancer as a Service. We are using Load Balancer as a Service offered by Rackspace. Rackspace does not charge or count the bandwidth used within their one data center (ServiceNet), so if one is using a Load Balancer only to assign an IP for MySQL database server, only the hourly usage will be counted. In case of concurrent connections over Internet ( Public Net ), however the bandwidth consumption will be counted.
As any load balancer from Rackspace will have a dedicated IP address, adding one load balancer in front one server instead of directly exposing the server’s IP will provide a kind of defense from the script kiddies. You might want to read Hardening Rackspace Cloud Server for WordPress to activate less known features like
ServerSignature to Off and activate
ServerTokens Prodon the main server running Apache 2.4
Basically, with one server with load balancer, the monthly charge does not increase much – the cost of bandwidth for the server is getting deducted. Total cost, practically increases by $10-$20 per month. One can close the PublicNet access to the main server and use the Console of Rackspace Cloud Control Panel to make the server fully inaccessible from outside.
Load Balancing in the Cloud : SSL and Non SSL
With Cloud Load Balancers, we can add the Key Pairs on the Load Balancer, the servers behind works as Nodes. There is extra charge for SSL based Load Balancers. We recommend to use a separate server for SSL website, which is the exact mirror of the non-SSL website but contains only HTML copies. For example, one can simple wget the contents of the non-SSL website from Server 2 and activate the SSL feature, add keys etc. As the content is static HTML and on SSL website we can not use several methods to serve and co-share session cookies to speed up, non-SSL with load balancer in front will face the main traffic and add some logical criteria to redirect to SSL counterpart.
Using SSL for the whole old site exclusively might give temporary good performance on SERP but it possibly will decline with time as the scope of Page Speed Optimization is lesser on servers with SSL. It is risky to use PHP to render the pages or cache, such as using cache plugins in case of WordPress. Keep in mind, you must use SSL CDN too for the HTTPS counterpart of your website. Otherwise, there will be mixed content error.
Other points like using a higher TTL, activating the caching feature on load balancer has been described in the linked articles.