CHAPTER 1 ■ INTRODUCING THE CLOUD COMPUTING PLATFORM
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Content Delivery Networks are essential for delivering dense web content,
especially media, to the user with low latencies. CDNs are a system of interconnected
and distributed cache servers located across the globe in a network. Multiple copies
of the content exist on these servers. When a user makes a request to the application,
DNS will resolve to a cache server based on location and availability. Microsoft Azure
Content Delivery Network Service and Amazon Web Services CloudFront Service offer
Content Delivery Networks to users. However, you can also consider other Telco and
Internet service providers for solutions. Before you sign up for a service, do have a long
conversation with the provider and verify there are adequate points-of-presence, or cache
server locations, in the geographic areas that are of interest to you.
Load balancing is to be considered if you want to improve the availability of critical
business applications; sustain agreed-to service levels for access and latency; and
distribute traffic for large, complex, and global deployments. Load balancing distributes the
incoming traffic to multiple instances of an application running on different data centers.
Load balancing can typically be used to distribute the traffic via three different methods:
Fai lover: Use this method when you want to use a primary endpoint for all traffic,
but provide backups in case the primary becomes unavailable.
Performance: Use this method when you have endpoints in different geographic
locations and you want requesting clients to use the “closest” endpoint in terms of the
lowest latency.
Round Robin: Use this method when you want to distribute load across a set of cloud
services in the same data center or across cloud services or websites in different data centers.
Load balancing is critical for failover scenarios—on detecting “failed” instances,
incoming traffic is routed to healthy instances, thereby ensuring high availability of the
application. Both cloud platform vendors provide a load-balancing service, via Microsoft
Azure Traffic Manager Service and Amazon Web Services Elastic Load Balancing Service.
Storage and Data Services
From providing storage and data services as virtual machines to the current sophisticated
service offerings, cloud platform vendors have covered much ground. In the remainder of
this section you will review the varied storage and data services offered by both vendors.
Databases
The database service provides you with the ability to manage relational data with built-in
high-availability constructs. Microsoft Azure SQL Database and Amazon Web Services
Relational Database Service (RDS) are considered Software as a Service (SaaS), and these
are available for integration with your applications. Databases, e.g., Microsoft SQL Server
or Oracle Database, are also available as virtual machines.
Cloud platforms provide relational databases for both cloud- and on-premises-based
business applications to use. Databases on cloud platforms are scalable to hundreds
and thousands of databases and can be scaled up or down depending on usage patterns.
These databases have two or more backups and will guarantee uptime. Data backup is
available for periods of up to a month and are great for the “oops I deleted it” scenario via
the point-in-time recovery option. The bottom line is that database administrators are able
to accomplish more since these databases self-manage and require little maintenance.