The two most important demands on any online service provider are availability and resiliency. It takes a server a certain amount of time to respond to any given request, depending on its current capacity. If during this process, a single component fails or the server is overwhelmed by requests, both the user and the business will suffer. Load balancing aims to solve this issue by sharing workloads across multiple components rather than using a single server, thereby ensuring consistently fast website performance at any scale.
Service providers usually build their networks through the use of front-end Internet-facing servers, which move information to and from back-end servers. The front-end servers typically contain load-balancing software that decides which requests to forward to which back-end server, determined by resource availability and a combination of internal rules and logic.
Key Benefits of Load Balancing
- Avoid service outages, providing users with fast, uninterrupted service even during traffic spikes
- Scale your application efficiently by distributing traffic across your origin servers
- Gain flexibility and control with your technical infrastructure
- Access real-time performance monitoring through metrics, logs and alerts
Local and Global Load Balancing
Local Load Balancing refers to load balancing within a single data center. There are two main reasons for deploying local load balancing: (i) To achieve high availability – for which you need at least two backend servers in case of failure; (ii) To gain access to a control point over your services – allowing you to configure filtering rules, change backends during deployments and manage the overall flow of your traffic.
Global Load Balancing refers to load balancing between multiple data centers. Global load balancing is necessary once a business reaches a certain scale of operations. The two main reasons for a business transitioning to a global load balancing solution are: (i) To avoid failure through the housing of all digital operations in a single building or region; (ii) For regulatory or jurisdictional reasons, for example, the need to keep European data within Europe, or to retain Asian traffic within an Asian data center.
The section.io Load Balancer
Most existing industry load balancing solutions involve a mixture of appliance-based application delivery controllers (ADCs) and cloud-based solutions. ADCs have evolved out of the earliest load balancer designs and are still the dominant model in use today despite their challenges in elastically scaling in real-time, and high costs for maintenance and support. Cloud-based load balancers can offer both cost savings and better performance; however, their main issue is that they are built on top of DNS, which means that they can only route traffic through use of the IP address. As they can’t see anything more within the request, they are unable to offer a single unified service for microservices. Cloud-based load balancers also rely on time to live (TTL), which involves caching responses from a DNS lookup and thereby limits immediacy and control.
With the section.io load balancer, however, decisions are made at Layer 7 instead of the DNS layer, which enables application-specific decisions on every single request. Additionally, failover decisions are made on every request, not just if the DNS cache expires. When your primary server is not available, automated failover to a different backend server kicks in meaning your users will never receive a 502 error.
With the section.io layer 7 load balancer, you are also able to gain a granular level of control and immediate scalability. You can programmatically determine your own custom routing rules, including request location, device or browser type, and cookies or headers, in order to immediately route HTTP and HTTPS requests. Our application layer load balancing service means that you can serve unique content to different geographic regions and unique content to different user browsers, as required.
Furthermore, the section.io load balancer can be utilized to randomly distribute requests to your origin servers to ensure that no single server gets overloaded, enabling immediate scalability and avoiding performance degradation or availability issues.
section.io offers git-backed version control for straightforward configuration, along with in-depth metrics and logs to transparently show you how each request was handled so that you can quickly diagnose any issues. We have also created a set of common load balancing scenarios in VCL, which you can edit via your section.io portal.
You can easily add other section.io services to guarantee a unified architecture across your complete application, deploying Varnish Cache and the ELK stack logs alongside the Load Balancer, for instance, to guarantee the easy handling of any traffic spikes and to optimize user experience.