What is clustered hosting? How to set it up for your web hosting?
Clustered web hosting is the latest trend in hosting industry, where cluster of multiple servers have replaced a single dedicated server in hosting the web sites.
In our role as Outsourced Support Techs for web hosting companies, we configure and manage hundreds of servers by setting up clusters, and thus help reduce the impact of a downtime in the business.
The key benefit of having a cluster setup is to minimize the impact of a business downtime. Even if one server fails, having other servers to take its place, helps to keep websites and mail online.
Today, we’ll see the main advantages of cluster web hosting and how we can set it up for your servers.
What are the benefits of clustered web hosting?
Having multiple servers is useful to provide increased reliability and performance to the websites. Even after setting up a cluster, we can easily add and remove servers from it, as and when a need arises.
In addition to this scalability and flexibility features provided by a cluster web hosting, it also ensures better load balancing across multiple devices and high availability of services even in case of a node failure.
By eliminating all single points of failure and providing enough redundancy, cluster web hosting helps to host large web sites and handle the peak traffic, in a fault-tolerant manner.
For websites that handle huge amount of data, multiple database and web servers are required to ensure 99.99% uptime. During maintenance and upgrades too, this clustered setup helps avoid a downtime.
As there are multiple servers hosting the same content in clustered web hosting, this setup can benefit from the processing power of the multiple servers in the system.
With a proper resource planning and distribution of websites among the various nodes in an efficient manner, cluster web hosting also helps ensure better hardware utilization of your infrastructure, such as the storage space.
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What are the multi-server clusters offered by cPanel?
Many web hosting control panels such as cPanel, Plesk and InterWorx offer out-of-the-box clustering abilities for DNS service, Database, Web servers and Configuration management.
As of version 11.56, cPanel offers DNS Cluster for high availability, and Configuration Cluster for easier server management. Here are the details:
DNS being the key service based on which other services such as web and mail operations, a downtime for DNS can affect the availability of other services too.
The DNS protocol requires that a domain should have at least two name servers. This is to ensure that even if one name server goes down, there’ll be another to keep the domain online.
However, in a default cPanel setup, this requirement of redundancy is not met. Yes, cPanel does allocate two name servers to each domain, but both name servers will be in the same physical server, which defeats the purpose of redundant name servers.
For servers running with cPanel/WHM as the control panel, cPanel has a DNS Cluster feature. By setting up the nameservers in different servers of the cluster, we avoid website downtime due to DNS service failures.
When we setup DNSONLY clusters, we maximize the cluster effectiveness and security by:
- Setting up the name servers in separate geographical locations for redundancy purposes
- Making all name servers “masters” to lower DNS update delays among them
- Securing the cluster against cache poisoning and other attacks
Configuration cluster (only for cPanel updates)
When you have multiple servers, logging in to each of them for client management or server administration can quickly get tiring. This led to many cPanel owners ask for a central configuration management system, which would help them to manage and update multiple systems from a single location.
As a first step, “Configuration Clusters” was released in cPanel v11.44. As of v11.56, the Configuration Cluster feature can be used to manage cPanel upgrade settings across multiple servers.
It allows managed VPS hosting providers, dedicated hosting providers or shared hosts with multiple servers to implement a uniform upgrade policy from a single “master server”.
Yes, changing update preferences is not something you do daily, but this feature is more like a technology demonstrator right now, with more configuration settings to be included later on.