AWS Availability Zones Offer High Availability and More
Apr 12, 2022
Despite the name, the cloud doesn’t exist in the atmosphere. At least not the kind of cloud that powers information technology. It’s located on earth, comprised of servers residing in data centers around the world that are accessed over the internet.
The location of those servers and the cloud resources they power doesn’t necessarily mean that’s where cloud services must be used. At least in terms of the big cloud services providers (CSPs), like AWS, Azure, and Google, where cloud services are delivered is a matter of availability regions and, even more so, availability zones (AZs). AWS offers the most among the big three CSPs, along with numerous resources to maximize their benefits.
Availability Regions and Zones Defined
To understand the value of the benefits AWS offers through its global cloud infrastructure, it’s important to understand the basics of how and where this infrastructure is deployed.
Availability regions are the geographic locations where the data centers of public cloud service providers (CSPs) reside. Regions are connected to one another through a backbone network. Different regions offer different service qualities in terms of latency and costs. Each region contains several AZs.
An AZ is an isolated data center within a single region, or several data centers located close to one another. It has independent power, cooling, and networking. And, there are high-speed, low-latency connections between AZs within the region. The idea is that if an entire AZ goes down, you can failover workloads to one of the other zones in the same region.
The AWS Setup
As of April 2022, the AWS Cloud spans 84 AZs within 26 global regions. This is the most of any CSP. Each region contains between two and five AZs that are geographically separated from one another.
In addition, AWS has announced plans for 24 more AZs and 8 more regions in Australia, Canada, India, Israel, New Zealand, Spain, Switzerland, and United Arab Emirates (UAE). All this amounts to a vast array of resources designed to give AWS customers the highest possible availability.
Each AWS region is isolated and operates independently from other regions. This is beneficial for workloads with high data sovereignty and compliance requirements that don’t allow user data to pass outside of a specific geographic region.
In addition, AWS control planes and the AWS management console are distributed across regions and include regional API endpoints, which are designed to operate securely for at least 24 hours if isolated from the global control plane functions without requiring customers to access the region or its API endpoints via external networks during any isolation.
Multiple Availability Zone Design
While some CSPs define a region as a single data center, AWS employs a multi-AZ architecture within each region to deliver resilience and ensure continuous availability. This ensures that customers avoid having a critical service dependency on a single data center. AWS can conduct maintenance activities without making any critical service temporarily unavailable to any customer.
Services can be replicated across multiple AZs to reduce latency or protect cloud resources. If an outage occurs, resources can be moved from one AZ to another.
All AZs in an AWS region are interconnected with high-bandwidth, low-latency networking, over fully redundant, dedicated metro fiber. This ensures high-throughput, low-latency networking between AZs. The network performance facilitates synchronous replication between AZs. All traffic between AZs is encrypted to ensure greater security.
AWS also makes partitioning applications for high availability easy. Partitioning refers to separating an application into components that run on multiple servers. Each of AWS’s AZs is physically separated by a meaningful distance from other AZs. If an application is partitioned across AZs, companies are better isolated and protected from issues such as power outages and natural disasters.
In addition, data centers located in different AWS AZs have a discrete uninterruptible power supply (UPS) and onsite backup generation facilities. They’re also designed to be supplied by independent substations to reduce the risk of an event on the power grid impacting more than one AZ. All AWS AZs are redundantly connected to multiple tier-1 transit providers.
AWS Tools and Resources
AWS does a few other things that make its regions and zones more beneficial and helps ensure greater availability. Among them is Amazon Route 53. It allows developers to redirect IP traffic from a failing or overworked region into an operational one. Developers can use Elastic Load Balancer to automatically distribute traffic to applications, which can run with Auto Scaling. This ensures that a particular workload always has the necessary computing power to meet demand.
Route 53 Traffic Flow enables even more complex setups using traffic policies. Customers can build a routing system that directs traffic to different cloud or on-premises endpoints based on geographic location, latency, and availability. Various third-party companies offer similar technology, but Route 53 Traffic Flow offers cost savings over those options.
AWS also offers AWS Local Zones. Each AWS Local Zone location is an extension of an AWS Region, and places compute, storage, database, and other AWS services closer to end-users. They provide a high-bandwidth, secure connection between local workloads and those running in the AWS Region. This allows for seamlessly connecting to the full range of in-region services through the same APIs and toolsets. These Local Zones facilitate running demanding applications, such as real-time gaming and machine learning, that require single-digit millisecond latencies.
Then there’s AWS Wavelength. Developers can deploy their applications to Wavelength Zones. These AWS infrastructure deployments embed AWS compute and storage services within telecommunications providers’ data centers at the edge of 5G networks.
Application traffic can reach servers running in Wavelength Zones without leaving the mobile provider’s network. This reduces the extra network hops to the Internet that can result in latencies greater than 100 milliseconds, preventing customers from leveraging the benefits of 5G.
Another helpful tool AWS offers is a price calculator. The prices of AWS services vary depending on the region. So the calculator provides an easy way to generate monthly cost estimates for any region supported by a desired service.
ClearScale and AWS Availability Zones
ClearScale has extensive experience working with AWS AZs and regions. You can learn about some of our efforts in these case studies:
Deep Automation Helps Coupa Scale Globally
Education.com Modernizes Its Online Education Platform by Migrating to AWS Cloud
To learn more about how ClearScale can leverage AWS regions and AZs to benefit your organization – as well as other AWS resources, contact us today:
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Read our Customer Case Studies