When creating and constructing services, reliability and resilience are crucial. REST APIs are frequently used in businesses to activate IoT devices and keep them connected to the internet. This service requires the maximum uptime attainable.
So, let’s discuss active architecture on AWS, why they are important, and how to build them.
What is an Active-Active Architecture?
An active-active architecture is a network of separate processing nodes that can independently interact with the same duplicated database to run a single application.
Across all useful purposes, we will run two or more “sets” of apps in two or more AWS regions that are separated geographically. In the event that one area fails, the other will be able to seamlessly pick up traffic flows from the affected zone without causing any outage for the users of the globally distributed application.
Reasons You May Consider a Multi-Region Active Architecture
Here are a few of the main justifications you might think about constructing a multi-region active-active architecture:
- Disaster recovery: Protect yourself from a regional failure.
- End users will benefit from improved latency – the quicker your backend is to the customers, the stronger the customer experience.
- Non-functional corporate criteria for Tier 1 applications with 99.99%+ availability.
With high-speed connection and reliability across a variety of network segments and geographies, AWS offers a stylish, worldwide network. These extensive worldwide networks can be used by businesses to create distributed software architectures and connect with customers throughout the world.
Now that we know why building a multi-region active architecture may be necessary; let’s find out the ways to build it.
Ways to Build a Multi-region Active Architecture
To put it simply, a multi-region active-active architecture deploys all services across the clients’ requested paths that are distributed across various AWS Regions. However, for this to happen successfully, several conditions must be met.
- Fast and dependable data duplication across regions is necessary.
- Establishing a worldwide network architecture to link your various regions.
- Services must be neutral and should distribute information among all regions; they shouldn’t have regional states.
- Implementing DNS routing will allow for a variety of eventualities.
- Apps must utilize regional resources.
- When feasible, synchronized cross-regional calls ought to be eliminated.
Let’s examine these conditions in more detail:
Data Replication Considerations
Let’s have a brief discussion of the CAP theorem. According to the Consistency, Availability, and Partition Tolerance (CAP) theorem, no network infrastructure can offer more than 2 of these 3 characteristics at once. Particularly in the case of system partition, one must pick between availability and consistency.
This leaves us with two options:
- Sacrificing consistency will keep the system strongly available
- Or sacrificing availability for consistent performance.
Because our target is to make an application AVAILABLE throughout various regions, we have no other option but to prioritize availability; it also implies that we must accept asynchronous technologies and replication.
Asynchronous replication for dispersed database systems separates the central node from its copies at the cost of adding replication delay or latency.
This implies that updates made on the central node do not always appear on its duplicates right away. This delay is what gives birth to eventual consistency. A framework is considered to have cointegrated or gained replica convergence when it reaches eventual consistency.
To accomplish replica convergence, software must balance disparities between numerous versions of different datasets. It can accomplish this by carrying out these various consolidations:
- Comparing different data versions
- selecting an arbitrary endpoint
- The data should be compared in a “smart” way.
Global Network Architecture
Some years back, while installing multi-regions architecture, it was normal protocol to set up encrypted VPN connections across regions in order to duplicate the information periodically.
While setting up and administering these connections has grown simpler, the key issue remained that they were connected to the network, leaving them vulnerable to sudden changes in connectivity and, in particular, latency, which made it challenging to sustain a reliable replication.
Vice President & Renowned Engineer at AWS, James Hamilton, revealed that AWS was now offering a fast broadband, global network infrastructure driven by independent 100GbE cables revolving around the world to address that issue.
As a result, AWS Regions are now linked to a privatized global network foundation, which offers better cross-region latencies at cheaper costs than the public internet. The advantages are obvious:
- Enhanced quality throughout, reduced network congestion and latency.
- Minimize bandwidth conflicts between network interconnects.
- Improved operational efficiency
Minimize Regional Calls And Utilize Local Resources
As was previously stated, it is essential for apps to avoid growing latency. To minimize latency, it is crucial to steer clear of simultaneous cross-region calls and ensure that resources are always accessible locally.
For instance, to provide access privileges from any location, assets hosted in an Amazon S3 bucket need to be replicated across several regions. Fortunately, Amazon recently introduced cross-region replication for Amazon S3 as a feature. With cross-region replication, items can be automatically and asynchronously copied between buckets within many AWS Regions.
Clients engage with a service through sessions, which are sets of interactions.
In a stateless design, the server must handle every user request separately from earlier queries or sessions and shouldn’t save any local records of client interactions. A stateless software should therefore give every end user identical output when provided the same input.
Due to the fact that any query can be serviced through any computer resources that are available, stateless apps can scale laterally (e.g., functions, containers, and instances)
A Domain Name System is required to distribute traffic across regions to enable adjustable routing algorithms.
Domain name registration, health-checking web services, and the Domain Name System (DNS) are all offered by Amazon Route 53. The capability for the flow of traffic across a number of routing algorithms, all of which may be paired with DNS recovery, is, however, what matters most for our application scenario.
- Utilize a geolocation routing strategy to route traffic according to where your consumers are.
- Utilize a Geo proximity routing strategy to direct traffic according to the geolocation of your resource and, perhaps, switch traffic from one place to the next.
- Employ a latency navigation protocol to direct traffic to the source that has the lowest latency once you have services spread across several locations.
- Utilize a weighted routing strategy to distribute traffic among several resources in the amounts you choose.
- Whenever you need Route 53 to react to DNS requests with over eight valid entries randomly chosen, use the multi-value response routing strategy.
Now we have covered how to create a multi-region active architecture, adopt asynchronous architectures and designs, and create entirely neutral apps. All the services upon a client request chain need to be distributed across various AWS Regions.
Of course, if we want to ensure accurate data replication, we must use highly available options like DynamoDB or Amazon S3 that take advantage of the global infrastructure that Amazon has built. Ultimately, we also outlined the need for flow of traffic in order to promote various routing regulations across AWS Regions.
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