HA Architectures
Successful businesses require production environments that are always available with minimal impacts for customers during application or infrastructure downtimes. Also, as businesses grow, their applications need to cater to varying traffic loads expanding and shrinking resources according to the traffic demands while optimizing costs. Amazon web services allow organizations to design and implement highly available and scalable cloud architectures to provide continuous access to the resources.
One of the techniques AWS cloud storage services use to achieve high availability is replicating data across different availability zones and regions. One example is Amazon S3 that offers cross-region replication that automatically replicates data to another S3 bucket in another region. If a disaster strikes affecting the primary region, you can restore the data from the replicated region, eliminating a single point of failure. AWS-managed database services also support data replication by maintaining read replicas in different availability zones. When the primary availability zone becomes unavailable, it can automatically promote the read replica to the primary database.
Multi-AZ Deployments
Cloud applications can be designed to become highly available by distributing resources across multiple availability zones. Multiple availability zones (Multi-AZ) allow your applications to automatically failover to healthy applications instances when the primary availability zone becomes unavailable with minimal impacts for your customers. For example, Amazon provides Multi-AZ deployments for Oracle, MySQL, PostgreSQL, and MariaDB databases. In a disaster for the primary database, the fail-over technology automatically switches to a standby database instance in another availability zone.
Fig1: RDS can achieve High-Availability through Multi-AZ deployments
Data Backups
Most cloud storage services offer automated backups providing point-in-time recovery in the event of a failure. For example, Elastic Block Store (EBS) volumes capture point-in-time snapshots and back up the data to Amazon S3. You can then use the snapshots to create new volumes and restore the data.
Elastic Load Balancing (ELB)
Elastic Load Balancing automatically distributes traffic across multiple AWS resources based on a specified routing method. Load Balancers carry out health checks for their registered targets and prevent sending traffic for unhealthy instances, ensuring the high availability of load-balanced resources.
Auto Scaling
If your application servers become suddenly unavailable due to an unexpected event, system failure, or any other reason, manually spinning up servers can take considerable time. Also, if your applications suddenly have a high traffic volume, you need to avoid overloading the existing server capacity. AWS auto-scaling lets you automatically scale your resources in and out based on the demand for your applications and constantly maintain the performance of your applications at a lower cost.
An auto-scaling architecture has auto-scaling groups that consist of the resources to scale. The launch template defines the minimum, maximum, and desired capacity of the resources at any given time. You can dynamically add or remove different resources like EC2 instances, DynamoDB tables, and Aurora replicas based on your defined scaling plan.
Fig2: AWS Auto-scaling Group
Auto Scaling with AWS Lambda, CloudWatch, and Amazon Route 53
AWS enables organizations to combine multiple services for maintaining high availability and scalability based on events. Using CloudWatch events, you can register events. For example, CloudWatch can monitor the CPU or Memory Usage of the EC2 instances in an auto-scaling group and trigger an event when the resource usage increases than the defined threshold value. CloudWatch then invokes the lambda function that instructs Route 53 to add more DNS records and Auto-scaling to add more resources.
Fig3: Dynamic Auto-scaling based on CloudWatch Events, Lambda, and Route 53
How Organizations Benefit From High-Availability and Scalability?
High availability and scalability are crucial components for all organizations that move their production environments to the cloud. Many organizations have achieved their desired business goals by leveraging auto-scaling to maintain the scalability and availability of their applications in the cloud. Applica is one such business that has gained many benefits by using auto-scaling for its AI-based solutions.
Applica is a company based in Poland that provides document automation services for websites. Their clients include large media companies that receive a high volume of user posts. The challenge company had was handling a high volume of unpredictable workloads without affecting their service responsiveness.
Leveraging auto-scaling and Amazon S3, Glacier, ELB in their cloud solution enabled them to scale their infrastructure ten times than its normal load to cater to sudden traffic spikes. Furthermore, the company has updated resources with minimum impacts for their customer base, ensuring high availability.
Summary
High availability and Scalability are crucial requirements for business continuity during unexpected events and sudden increases in traffic demands. As we described in this article, AWS provides different techniques for High availability and Scalability of their storage, compute, and databases. Ensure that your business takes the maximum benefits from leveraging these techniques to provide continous services to your customers.
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