Concert.ua Manages 1000% Traffic Spikes Using AWS Serverless

Ukrainian event ticketing company Concert.ua experienced unexpected spikes in traffic that overwhelmed its website, leaving customers unable to complete transactions. Using fully automated scaling and a serverless architecture built on Amazon Web Services (AWS), the company has increased the reliability and availability of its systems and reduced infrastructure costs. Its customers are able to reliably purchase tickets for popular events, even when traffic is high.

Dealing with 1,000% traffic spikes

Concert.ua is Ukraine’s largest ticketing agency and handles almost half of the country’s online ticket sales. To win over customers, it needs to provide fast and reliable services so event-goers don’t choose to purchase tickets from competitors.

Concert.ua had migrated to a small cloud provider in 2017 but the arrangement was frustrating the company. Although the cloud was more efficient and flexible than managing its own on-premises servers, it had to provision servers manually, a process that could occupy several staff for many hours.

The announcement of a popular event, or a mention in social media, results in a sudden influx of visitors to the Concert.ua site. This causes traffic increases of anywhere between 400 and 1,000 percent within minutes.

Before using AWS, technical staff estimated how many servers were needed but often ended up overprovisioning and paying for unused resources. “Even when a traffic spike was expected, it was always a guess as to how many servers we’d need,” says Yevgen Lysenko, founder and chief technology officer (CTO) at Concert.ua. “But there was no other option with the resources and technologies we had at the time.”

Concert.ua wanted to find a solution that would allow its staff to focus on improving its ticketing application and working on innovative marketing strategies instead of spending time troubleshooting its infrastructure. “Looking after the infrastructure was a never-ending story,” says Lysenko. “Something was always wrong and we never had enough people to do all the work.”

Concert.ua turned to AWS for out-of-the-box services that would automatically scale fast enough to deal with unexpected traffic spikes.

Migrating to a Serverless Architecture

Concert.ua transitioned from its traditional approach of service provisioning to infrastructure as code, using the open-source Terraform tool.

The company migrated to AWS Lambda, a serverless, event-driven compute service that lets you run code for virtually any type of application or backend service without provisioning or managing servers. Concert.ua also used Amazon Aurora, a MySQL and PostgreSQL-compatible relational database built for the cloud.

To automatically scale up or down to handle traffic spikes, Concert.ua initially chose to use open-source Docker containers to package its SQL database. It then uploaded them to Amazon Elastic Compute Cloud (Amazon EC2), which provides secure and resizable compute capacity.

Some initial provisioning experiments reduced the time to spin up a server, but the solution was still too slow to deal with sudden large spikes in traffic. So Concert.ua tried AWS Fargate, a serverless, pay-as-you-go compute engine.

Lysenko admits he was surprised by the results. “We didn’t think Fargate would be useful, but we quickly changed our minds once we tested the service. We discovered that it not only scales much faster, it’s also cost efficient. Fargate containers are twice the capacity of our previous containers, and so we use fewer containers than expected,” he says. “We were looking for a magic button that we could press to make our transaction processing run faster. Instead, we found AWS Fargate.”

Delivering Real-Time Transactions Using AWS Lambda

Before using AWS, when a customer purchased a ticket during a busy period, they had to wait for the database to work through a queue of requests before receiving a confirmation.

Now Concert.ua uses AWS Lambda to process multiple transactions simultaneously—so customers no longer have to wait. As soon as they complete their transaction, Concert.ua generates and dispatches the ticket. “Using AWS Lambda and AWS Fargate, we can have simultaneous transactions running in real time,” says Lysenko. “Everything just works and it’s all automated, which is fantastic.”

Getting 99.9% Uptime for Less Cost

Concert.ua’s ticketing site can handle large, unexpected spikes in traffic and reports 99.9 percent uptime. In addition, its technical staff focus on higher value projects that helps the business grow its market share and further improve customer experience.

The migration has improved system reliability while also reducing the cost of operating its ticketing infrastructure. “When we used the AWS calculators we were unsure how much the services might cost us, but most of the time our bill has been less than we estimated,” says Lysenko. “The bill is always relative to our business activity, so when the bills are high it means that we have been earning more.”

Concert.ua developers have also reduced the time it takes to implement APIs using Amazon API Gateway and AWS Lambda.

Instead of spending time coding, the developers send high-level instructions to AWS Lambda and can manipulate backend services to access data, business logic, and application functionality. “We couldn’t launch APIs as quickly as we can now,” says Lysenko. “Previously, we had to do a lot of coding but now it’s 300–500 percent faster. Using AWS, our software development cycle takes less time and effort, by fewer people. And it costs less than our previous setup.”