Recently, the term ‘load balancer’ has become popular and is being used extensively by organizations. This popularity is because these appliances come with a range of crucial features for managing business applications running on the cloud or on-premises.
A load balancer is a hardware or software-based network appliance that helps distribute workloads across multiple computers, servers, CPUs, hard drives, or other resources. This should be done so that the additional resources are used to satisfy current demands, thus avoiding resource overflow and making efficient use of your resources.
Different load balancers help bring up routines to handle services. These can be as follows:
Internal Load Balancers
Internal load balancers are used for requests originating from within a VPC or an on-premises network, both of which are connected to the load balancer via its routed network interface.
This load balancer is configured to provide TLS termination, act as an SSL proxy, or forward unencrypted requests. Internal Load Balancers (ILB) improve application availability by routing inbound traffic through healthy service instances inside your VPCs. They also ensure only healthy service instances are used at any given time.
The network traffic to the service itself does not have to traverse the load balancer, so it doesn’t need public IP addresses. You can use an ILB to share a single public IP with multiple services running within your VPCs. This is particularly useful for hosting services over multiple regions, as it reduces the need to use separate public IPs for each public endpoint.
External Load Balancers
External load balancers are used for requests that originate outside of your VPC or on-premises network, which are then forwarded to an internal load balancer using a one-armed proxy configuration.
The access logs for an external load balancer show all incoming requests, whether they were initiated internally or externally. Load Balancers can be used in several ways:
Improving Application Availability And Scalability
The traffic to the service itself does not have to traverse the load balancer, so it doesn’t need public IPs. Load balancers can be shared between multiple services hosted within VPCs.
Improved Application Security
All access to the service is through the load balancer, which is configured to provide TLS termination, SSL offloading and HTTP/2, etc.
Optimizing Resource Utilization
Relatively newer tools such as AWS Auto Scaling allows you to build scalable and cost-effective solutions for processing traffic at the network edge.
Improving Application Performance
The load balancer can be configured to manage connections, balance load, terminate SSL, etc.
Enabling HTTP/2: Load Balancers Support HTTP/2 And Server Push Out Of The Box
These services become essential when you have a large amount of traffic going to your services, which is why they are used in conjunction with several other strategies such as Auto Scaling.
Application Load Balancer (ALB) Using Ingress Controller Cluster
An application load balancer is a fully managed service that makes it easy to load balance traffic across multiple AWS EC2 instances or Amazon ECS tasks. You can use ALB to layer network traffic and security policies on your application, so you don’t have to manage the underlying infrastructure such as VPCs, subnets, Elastic Load Balancing load balancers, security groups, or certificates.
ALBs allows you to write rules that route traffic based on criteria such as the content of the request, HTTP headers, and cookies in the request, IP address range, geo-location, the type of application your users are using, or the type of application your users are using custom metrics supplied by your application. You can also use ALBs to encrypt traffic between your users and load balancers.
Network Load Balancing (NLB) monitors network issues such as network traffic, bad network path, and network latency. NLB works by using a single virtual IP address shared across the cluster instead of using individual IP addresses for each cluster member.
NLB enables network administrators to monitor issues happening on their network and keeps network services running even when network problems occur. By distributing network load across multiple servers, NLB can help reduce network congestion and lessen the damage done by network issues.
The network administrator needs to create a network load balancing cluster, define a network health probe for monitoring, configure load balancing settings to the network, ensure network fault tolerance and manage the network load balancer. The steps are explained below:
A network load balancing cluster is created using the Network Load Balancing Manager. A network adapter with a network load balancing driver is configured for each network interface.
A network health probe is created to monitor network issues such as packet loss, latency, and network traffic. The network administrator can automatically configure the network load balancer and monitor the load balancer process using performance counters.
The virtual IP address mapping is configured, network load balancing rules are created, and network affinity is set. The network administrator can also configure the network load for specific network services like HTTP server farms, FTP file servers, etc.
If the service stops due to unexpected network issues or hardware failure, then all network member nodes belonging to the NLB cluster should be stopped. If network traffic is still passing through the cluster, network clients will receive network error messages.
The network administrator should monitor network issues using the network health probe and update the network load balancing settings to re-balance network traffic or reduce network latency. The events can be monitored using Network Load Balancing Operational logs.
The network administrators can divide network traffic among multiple network servers or network interfaces to distribute network workload and ensure that network services are available even during network issues. This helps to keep network clients connected to the server by monitoring network problems like packet loss, latency, and network traffic. It ensures network fault tolerance by distributing network load across multiple servers.