This PPT provides information on DNS clusters, their management, their requirements and structures along with cluster members’ failure threshold.

1. A Comprehensive
Guide for DNS Cluster
Configurations

2. Table of Contents
2
DNS Cluster
DNS
Web Hosting
Managing DNS Clusters
Cluster Members’ Failure Threshold
DNS Cluster Requirements
DNS Cluster Structures

3.  A DNS (Domain Name System) cluster refers to a collection of nameservers. This
groups shares records among each other. It serves the purpose of separating in
physical form the nameservers that are handing the web servers’ DNS requests. It
makes it possible to configure a DNS cluster, so that servers could be added to a
DNS cluster that already exists.
3
DNS Cluster

4.  DNS is the abbreviation of Domain Name System. It refers to the naming system
used by computers and other resources that are connected to either a private
network or to the Internet. It is decentralized as well as hierarchical. It is the DNS
that ensures the delegation of the task which caters to the assignment of domain
names and mapping those to Internet resources. Moreover, the more easily
memorized domain names are translated by it to IP addresses that are numerical.
These IP addresses are needed to locate and identify computer services and
devices. The technical functionality of the service related to database is also
specified by DNS.
4
DNS

5.  In the context of the Internet which is used to browse innumerable websites, web
hosting is important to mention. Web Hosting refers to the leasing of server space
along with providing the necessary service and technology to make a website
accessible over the Internet. There are many website hosting service providers (also
referred to as web hosts) that offer various plans for various types of web hosting,
such as shared, dedicated, resellers,WordPress, cloud etc.
 The terms that are often heard in the context of web hosting are “Top Cloud
Hosting Company”, the “Best Website Hosting Company” and the “Best Windows
Hosting Company”. These refer to web hosts that excel in the quality of services
provided by them.
5
Web Hosting

6. 6
1-800-123 -8156
Whoa!That’s a big number, aren’t
you proud?

7.  Those users who have the All ACL privilege are able to add to a DNS cluster their
own custom DNS servers. Such users who possess this privilege also have the
ability to make changes to the cluster members that exist. Modifying DNS cluster
settings involves choosing between managing one’s DNS clusters as the root user
or in the form of a reseller from the Managing DNS Cluster as: menu.
 Prior to the addition of custom DNS servers or making changes to existing cluster
members, one is supposed to choose the root setting that is in the Managing DNS
Cluster as: menu.
7
Managing DNS Clusters

8.  The failure threshold with regard to cluster members’ setting enables the user to specify that particular
number of DNS Admin commands that are allowed to fail, prior to WHM disabling a DNS cluster member that
is unresponsive. It is advisable to disable an unresponsive DNS cluster member in order to aid improvement in
performance.
 The steps that need to be followed in order for the failure threshold for cluster members’ setting to be
configured are mentioned below-
 Step 1- Selection of the desired setting. A user should opt for 10 (Default) to use the default setting. In
this setting a cluster member is permitted to fail DNS Admin commands up to 10 times. It is usually
recommended to use this setting. Next the second setting should be chosen, so that the custom failure
threshold could be entered. It is advisable to increase the count for failure number in those situations where
the server down time is frequent and network interruption happens frequently. This ensures that certain cluster
members are not marked offline by the system. If the user wants to keep all of the servers in his DNS cluster
online perpetually and doesn’t want to consider the number of DNS Admin commands that have failed, then he
should opt for “Keep all cluster members online at all times”
8
Cluster Members’ Failure
Threshold

9.  Step 2- “Receive a notification when WHM disables an unresponsive cluster
member” option should be selected in order to receive notifications in that case
when an unresponsive member in the DNS cluster is disabled. Disabled cluster
members must be enabled manually.
 Step 3- The option to change must be clicked. In the scenario when any cluster
member that is in the sync role is found to be offline for a very long period of time,
the other server’s zones need to be resynchronized. This keeps the cluster member
updated.
9
Cluster Members’ Failure
Threshold

10. Certain minimum requirements need to be met in order to configure a DNS cluster. These are
mentioned below-
 A minimum of 2 servers must be present in the clusters.
 There must be at least 1 cPanel and WHM server present with cPanel and WHM installed. A scenario
involving a DNS cluster that has more than 1 of these, also functions properly.
 Every machine that is in the DNS cluster needs to have cPanel and WHM or have a version 11 or
higher of cPanel DNS Only installed. This is necessary as some of the features of cPanel and WHM
might not function with versions that are old.
 The most efficient structure should be considered prior to setting up the DNS cluster. The speed of
resolution of DNS requests is determined by the way in which each server is linked.
 To digress, terms such as “Top Cloud Hosting Company”, the “Best Website Hosting Company” and the
“Best Windows Hosting Company” are used for those web hosts that provide reliable web hosting
services.
10
DNS Cluster Requirements

11.  Direct links should be used- When there are multiple steps present between a cPanel and WHM and a
nameserver, then the speed of servers tend to decrease. It is advisable to link cPanel and WHM server to the DNS
servers directly, in order to enhance the performance of the servers. This ensures the elimination of the steps
performed by every request. Hence, the DNs requests get resolved swiftly. It is optimal to have a direct link
between each of the 2 nameservers and the web server. Such a configuration can be created by one cPanel and
WHM server with the need for nameservers that can be one or more in number.
 The primary nameserver should be used as an intermediary- If the need arises, the primary nameserver can be
placed between the cPanel and WHM server and the nameserver that is secondary. Any intermediate server that
gets added will slow the data transfer speed to three times in comparison with that for a direct link. An
intermediate nameserver that is present between the web server and that nameserver that is secondary is
admissible. For the creation of such a configuration, one cPanel and WHM server with a minimum of 2
nameservers is needed.
 Multiple intermediary nameservers should be used- In this configuration multiple steps are used between WHM
server and cPanel and nameservers. A minimum of two cPanel and WHM servers along with a minimum of two
nameservers is needed for the creation of this configuration. Such a configuration is known to reduce the servers’
response time significantly. This is not a method that is advisable as it reduces performance considerably.
11
DNS Cluster Structures

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