Not everyone runs multiple servers, so not everyone needs a load balancer. However, if you have multiple servers, clouds, or data centers, you either have a load balancer or you need one - or maybe more. Here's an update on what you need to know about managing your servers with load balancers.
What Is a Load Balancer?
A load balancer is a networking function that distributes traffic between two or more servers or other backend resources. These backend resources could be in containers, virtual machines, and even different clouds or locations. The purpose of a load balancer is to prevent your servers and resources from being overloaded, improve efficiency, and provide users with a fast, reliable, and secure experience.
The need for load balancing became critical when internet traffic grew and traffic loads on individual servers became hard to manage. Companies that were active online found that forecasting and planning for surges in external traffic (ingress) was more difficult than planning for internal application traffic. The need arose to distribute the workload between two or more servers or locations, and an automated solution was required.
Why Do You Need a Load Balancer?
Your organization needs to keep its servers online, secure and operating at peak efficiency. This is important for internal use such as Exchange, databases, and remote desktop, and for external use such as traffic to your public website or SaaS application.
You also need to keep your servers running fast. Kissmetrics, a company that specializes in internet conversions, points out research that indicates that 47 percent of consumers expect a web page to load in two seconds or less, and 39 percent will leave a website that takes longer than three seconds.
Load balancers are the answer to the issues of downtime, traffic surges, and failures.
What Are the Advantages of Load Balancers?
If you have two or more servers, you need to consider using load balancers. The benefits you'll receive are wide-ranging.
Handling Peak Demands
It's exciting to see the traffic to your website increase. However, if your website response slows down significantly, you'll lose visitors. A load balancer will help you ensure that your websites don't slow down due to increased traffic by distributing traffic to healthy servers with available capacity. An autoscaling load balancer (more typical in cloud-native environments) will automatically scale itself out to provide additional load balancing capacity if the traffic is more than it can handle with the current instance(s).
Maintenance is critical to keeping your servers running smoothly. However, it's often impossible to schedule downtime to avoid inconveniencing your users or website visitors. A load balancer will help you perform server maintenance without incurring downtime by automatically routing traffic to healthy available servers so users and website visitors will not experience any interruption to their sessions.
It doesn't matter what you do – failures are going to happen. A load balancer will detect a server failure early and route traffic to healthy servers still in operation. If a data center, cloud, or geographic location becomes unavailable (for example, because of a severed cable or public cloud failure), a load balancer will route traffic to the nearest healthy location based on latency and health checks. The result is that failures cause minimal to no disruption in operation.
Monitoring Application Health
For your web strategy and infrastructure planning, it's important to know how your applications and servers are performing and where the bottlenecks are. A load balancer will provide detailed performance metrics, error alerts, and reporting, so your organization can plan, adjust, and optimize its infrastructure.
How Do Load Balancers Work?
Load balancers typically have the following parts.
- Control plane: this determines the routing logic for distributing traffic between servers. There are different load balancing algorithms for different use cases.
- Data plane: this performs the packet forwarding to execute the routing determined by the control plane.
- Management layer: this provides a user interface for managing the load balancer. Typical user interfaces include web GUI, command-line interface (CLI), and an application programming interface (API).
Some modern load balancers decouple the control plane from the data plane, allowing for centralized control of many distributed data plane nodes.
Layer 4 vs Layer 7 Load Balancers
Within the Open Systems Interconnect (OSI) model there are two layers at which load balancing can function, Layer 4 and Layer 7. There are differences between load balancing in Layer 4 and Layer 7. Learn more about why to use a layer 4 or layer 7 load balancer.
Hardware vs Software Load Balancers
Load balancers have evolved from hardware appliances to virtualized software appliances to cloud-native functions.
At the beginning of the evolutionary scale are load balancing hardware devices. Where a hardware assist is needed, hardware devices can work efficiently up to a specified load.
With advances in server hardware and architecture, it's not necessary to tie load balancing to specific hardware configurations or ASIC-based hardware. Virtualized software load balancers offer greater flexibility and scalability.
Cloud-native architectures include public cloud service providers, edge computing networks, and distributed applications deployed as containers and microservices. This architecture typically requires components to increase capacity by scaling out rather than scaling up. Traditional hardware and software load balancer appliances do not scale out well. Cloud-native load balancers are designed to be lightweight, autoscaling, and centrally controlled.
Application Delivery Controllers (ADC)
Load balancers are often incorporated with other mission-critical functions and the result is called an application delivery controller (ADC). Other functions typically include global server load balancing (GSLB), web application firewall (WAF), and web accelerator.
App Services Platform
A modern alternative to an ADC is an app services platform. These also incorporate load balancers with other app services but are typically more extensible, scalable, and controllable. Other functions typically include web application firewall (WAF), API gateway, and Kubernetes ingress controller.
The type of load balancer that's right for you will depend on your systems and your objectives. Careful selection is important to ensure that you get the right optimization without going beyond what you need.
Book a demo with our technical team to find out more about Snapt’s load balancer and app services platform and how we can help you to guarantee enhanced service across your enterprise.
Otherwise, jump in and request a free trial of Snapt Nova and get started today.