As we've already discussed system design and why it is important for any software development. We have also looked at the plan and the design that acts like a blueprint for creating strong and reliable software or products. Now, let's understand the crucial components that transform these blueprints into dynamic, high-performing software, we are going to be talking about the role of load balancers.

Load balancers are those traffic management cops in software design that divert the traffic to less crowded roads to make space for everyone and avoid any traffic jams making the software development efficient. You can even call it an architect as it carefully plans the network of roads. Just as the real world demands efficient traffic management for smooth flow, the systems necessitate load optimisation for optimal performance.

This guide has got you covered on load balancers. We'll dive into their importance, different types, and strategies for implementation. So, buckle up and get ready to become a load balancer expert!

In case you are curious and want to know all about AWS recent ban on reserved instances.

What is load balancing?

The load balancer holds significant weight in network architecture. Load balancing equally allocates incoming network traffic, ensuring the effective utilisation of resources. It serves as the middleman between client requests and multiple servers or resources, its primary aim is to prevent an excessive influx of requests from burdening a single server. This means load balancers enhance the reliability, accessibility, and efficiency of applications and websites.

Currently, applications have been asked to efficiently manage a huge user base while delivering prompt and accurate responses like answers, multimedia content such as videos and pictures, etc. The enormous influx of user activity necessitates the implementation of numerous servers that collectively store and distribute the same information. Likewise, distributing replicated copies of a book throughout various locations ensures swift access for all, minimising waiting times.

Why is load balancing crucial in software development?

Availability

Server failure or maintenance can lead to extended periods of application unavailability, causing inconvenience for your visitors. However, implementing load balancers significantly enhances the reliability of your systems. These load balancers offer an intelligent mechanism for identifying server issues and efficiently redirecting client traffic to operational servers. By leveraging load balancing, you can effortlessly carry out the following tasks.

• Conduct application server maintenance or upgrades without experiencing any application downtime.
• Ensure automatic disaster recovery by seamlessly redirecting traffic to backup sites.
• Perform regular health checks to prevent any potentially detrimental issues that could result in application downtime.

Scalability

It can be achieved through the strategic utilisation of load balancers to effectively distribute network traffic across multiple servers. Using this approach, the system can handle bazillion requests. Load balancing provides the following advantages.

• By evenly distributing the network traffic among various servers, load balancing eliminates the risk of congestion and ensures smooth operation.
• Load balancers add or remove servers from the system depending on the changing demands.
• Load balancers make sure to protect against the failure of individual servers, ensuring uninterrupted service availability. You can confidently scale your applications while maintaining high levels of reliability and performance.

Security

Load balancers have security features that provide an added level of protection for internet applications. It effectively handles denial of service attacks, wherein servers get overwhelmed due to a huge number of requests leading to server failure. Moreover, load balancers offer the following.

• By actively monitoring incoming traffic, load balancers can identify and prevent incoming harmful content, thereby safeguarding applications from potential threats.
• Load balancers possess the ability to automatically redirect attack traffic to multiple backend servers, distributing the load and minimising the impact on individual servers.
• An additional layer of security can be implemented through load balancers by routing traffic through a group of network firewalls.

Performance

Load balancers enhance the overall efficiency of applications by increasing the response time and minimising network latency which means the time taken to send a response. Load balancers offer other functions as well.

• Equal distribution of workload across servers to boost application performance.
• Efficiently directing client requests to servers located in closer geographical proximity to lower the latency.
• Guaranteeing the dependability and optimal functioning of both physical and virtual computing resources.

These advantages make load balancers an important component of system design. If you too are curious about how load balancing can specifically benefit your software development project, let us connect over a free 30-minute consultation call.

Types of load balancing

DNS load balancing

• It is the effective distribution of network requests preventing overload on any single server to make sure every user has an overall better experience. Whether your service represents a website, email system, or any online platform, DNS load balancing ensures uninterrupted availability by redirecting users to available resources. It connects the user requests to the nearest spot to reduce latency.
• For example, the airport has several check-in counters to handle the flow of passengers. Similarly, a website may have multiple servers to manage user requests. DNS load balancing guides each user to an available server, spreading the load effectively.

Application load balancing

• Currently, applications have multiple server groups, each with many servers doing specific jobs. Application load balancers make sure everything runs smoothly. These smart balancers look at what each user is asking for, like the type of web page they want or their security information. Then, they send these users to the right server, making sure everyone gets what they need quickly and without burdening any single server.  
  
• For example, in a video streaming app, application-based load balancing directs users' video requests to designated servers specially optimized for streaming. And when it comes to logging in it is sent to different dedicated servers.

Network load balancing

• Network load balancers take the help of IP addresses. It analyses the origin of the request and distributes it across multiple servers by assigning them static IP addresses. Network load balancers use both static and dynamic techniques..
• Static techniques stick to a set of rules and work independently of what's going on with the servers at the moment whereas, dynamic techniques consider what's happening with the servers right now before deciding how to distribute the traffic.
  
• For example, the air traffic control tower ensures an efficient distribution of planes to different runways. This prevents congestion, optimizes runway usage, and maintains a smooth flow of air traffic by looking into the runway availability, plane size, and optimal routing.

Global server load balancing

• In this type of load balancing, first, the local load balancers manage the request or the load in a region and then redirect it to a location that is closer to the user. In case a server fails in the zone that is near to the user then it will be sent to some other server that is outside the user’s geographic location.
  
• For example, if a user is in Asia and sends a request to visit an e-commerce site, the request is sent to the nearest data center in Asia.

Load balancing in cloud environments

Cloud load balancing is the managing of workloads. When there are a lot of requests to be catered to, cloud load balancing helps by distributing the tasks across many computers, networks, or servers. It's like having a team where everyone does a fair share of the work.

Imagine the Internet is like a busy road, and all the tasks are cars trying to move. Cloud load balancing works like a traffic guide, making sure no road (or computer) gets too crowded. With the workload on the Internet growing fast, some computers might get too busy, especially popular web servers.

So, cloud load balancing steps in to prevent any server or resource from getting overwhelmed. It keeps things balanced, ensuring all servers handle their part of the work. This way, the response stays fast, popular websites don't slow down, and everyone gets what they need. 

Below, we look into the cloud platform's prominent providers: AWS, Azure, and Google Cloud. We analyze the functionality and features of load balancing in these platforms, highlighting their capabilities and benefits.

AWS elastic load balancing (ELB)

AWS Elastic Load Balancing (ELB) offers various load balancing solutions tailored to meet specific requirements within the AWS ecosystem. This includes Application Load Balancers (ALB), Network Load Balancers (NLB), and Classic Load Balancers. Each of these options has been carefully designed and personalised to excel in different use cases across the AWS environment. 

Azure load balancing

Azure's load balancing works like an organiser. It works smoothly with many other tools in Azure, helping businesses grow and handle problems without any interruptions. It's like having a safety net in case something goes wrong, making sure everything keeps running smoothly.

Google Cloud load balancing

The load balancing service of Google Cloud is like a menu with lots of choices. It's designed to meet the needs of the customers. You can pick how you want things balanced, like external or internal load balancing, and global or regional load balancing. There are also different service levels, like premium or standard. You get to decide how you want things to work, whether it's like a proxy or pass-through.

Autoscaling in cloud computing

Autoscaling in cloud computing helps organisations manage their cloud services well. It's like having a smart system that can handle how many servers are needed based on how much traffic there is. Big cloud computing companies like Amazon Web Services (AWS), Microsoft Azure, and Google Cloud Platform (GCP) have autoscaling tools.

One of the best things about autoscaling is that it saves money. It does this by automatically changing the number of servers when more or less are needed. So even if there are sudden changes in demand, autoscaling keeps everything running smoothly.

Autoscaling is effective because it takes away the need for people to manually add more servers when there's a sudden increase in traffic. This makes things a lot easier because it saves time and effort.

Load balancing best practices

Scalability planning

As we discussed above that the auto scaling is one of the best practices to handle a lot of traffic without spending much money similarly there are other tools with which we can scale the system. Scaling requires thorough planning based on different factors. Such as containerisation, it is best if you need to scale or just in case want to remove systems according to the demand. The technologies include Docker which is a lightweight and easier way to package the applications and their requirements.

Monitoring and analytics

Another way to scale your applications is by assessing their scalability requirements. You can do that by first, testing the load handling capacity and how they perform under various workloads. Second, check their performance by integrating tools such as Prometheus, Grafana, and CloudWatch in the applications based on metrics like response time, and ratio of accurate answers to wrong ones in real-time.

Disaster recovery planning

Planning for server failures is your application protection net if not done you might lose the data and the users. 

Load balancing and software development services

Integration with DevOps

• DevOps is the development methodology that helps developers develop and deploy applications quickly. To achieve this, organisations require automation and orchestration tools.
• DevOps needs automation tools to handle repetitive processes and these tools will be controlling load balancers, a compatible API in load balancer helps to communicate.
• Now, the automation tool will communicate and give commands to the API load balancer will achieve the goal quickly because there is no more requirement for manual assistance.

Impact on user experience

• At this point, we are already familiar with the versatile nature of the load balancers and we do have an idea how they help improve the user experience.
• After all, we have read, we can conclude that every online business can provide quality experience to their users. The result is increased scalability, redundancy, and optimised performance.

Case study

Company

Terminix - AWS Load Balancers for Scalability and Security

Challenges

Terminix faced downtime, scalability issues, and security concerns with outdated on-premises firewalls, impacting overall efficiency.

Objectives

Modernise digital infrastructure for better availability, scalability, and security. Reduce downtime, enhance bandwidth, and simplify architecture.

Achievements

Scalability: Gateway Load Balancer increased throughput by 300%, addressing server overload issues during peak times.

Reliability: Achieved 99.999% availability, eliminating susceptibility to VPN failures and increasing resiliency by 100%.

Efficiency: Automatic connection monitoring reduced time to recovery by up to 83%, ensuring minimal impact on users.

Simplified architecture: AWS CloudFormation streamlined onboarding, reducing the time from days to minutes.

Future plans

Terminix plans to migrate more legacy parts and execute a significant data migration to a cloud data lake, building on the success of load balancing for increased efficiency and throughput.

Implementing load balancing

Let’s create and configure a load balancer from scratch. We’ll be creating this load balancer on AWS. 

Step 1

Log in to your AWS account, refer to this guide to set up an account.

Step 2

Set the region where infrastructure will be created in the upper right corner.

Step 3

Select the EC2 Services.

Step 4 

Create a load balancer from the load balancer section.

Step 5 

Press the button to create a load balancer.

Step 6

Select the type of load balancer, layer 4 or layer 7.

Step 7

Assign a name to VPC and the listener.

Step 8

Choose the port that will receive the traffic and determine where it should be redirected to (for virtual machines).

Step 9

To establish the subnet, follow these steps

Step 10

To enhance security, it is recommended to create a dedicated security group for the load balancer. This security group should only allow access to ports 80 and 443.

Step 11

To create an SSL certificate, you need to upload it.

Step 12

Choose the previously created instance, At the end, click on create.

Now, review all of the steps to make sure everything has been done according to the steps and there is no error. 

Load balancers are important in today's system architectures to handle incoming traffic and improve system performance to improve the user experience. By smartly distributing the requests and monitoring server health they ensure scalability and high availability. It helps in optimal resource utilisation and running applications smoothly. The developers in any organisation need to educate themselves on the key concepts and working principles of load balancers to design and maintain scalable and reliable systems.  

Now to move on to the next step, check out this guide for CI/CD integration.

If you are looking for a team that is 100% onboard to turn your ideas into a scalable system, let's talk.