148422597X Kubernetes Management Design Patterns [Vohra 2017-01-29] {E559F6BB}

CHAPTER 16
Developing a Highly Available
Website
In Chapter 4 we used multiple AWS availability zones to provide fault tolerance for failure of a zone. But a
high-availability master was not used, and the single master is a single point of failure. In Chapter 15 we did
use a high-availability master with OpenShift and Ansible, but the single elastic load balancer remains a
single point of failure.
Problem
For a high-availability website, multiple public DNSes need to be configured. Another problem is that
Amazon Elastic Load Balancers do not support Inter-AWS Region High-availability Architecture, in which
the multiple master controllers in an HA master can be located in different AWS Regions. Amazon Elastic
Load Balancers only support Inter-AWS Zone High-availability Architecture within the same region. While
AWS zones are in different physical locations and are insulated from each other (failure of a one zone does
not cause failure in another zone), the HA is not spread across a wider geographical region.
Solution
Amazon Route 53 provides DNS failover, using which a high-availability website may be developed. Route
53 provides DNS failover across AWS regions as shown in Figure 16-1. Route 53 DNS failover can be used
to run applications across AWS zones or regions and configure alternate elastic load balancers to provide
failover across zones or regions. Route 53 DNS failover is not a Kubernetes design pattern but makes use of
the Amazon Route 53 Primary-Secondary architectural pattern.
© Deepak Vohra 2017
D. Vohra, Kubernetes Management Design Patterns, DOI 10.1007/978-1-4842-2598-1_16
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