What is a Load balancer?
In a load balancer, traffic is distributed across servers acting as a reverse proxy. An application load balancer increases capacity and reliability. Through the management and maintenance of application and network sessions, and as a result of performing application-specific tasks, they improve application performance overall.
What is load balancing?
An application or website under strain eventually cannot be supported by a single server. Multiple servers are used to meet demand. A “load balancing” practice allows one server not to become overburdened, which could slow it down, result in requests dropping, or even cause it to crash.
These critical tasks are performed by load balancing:
- A single server is able to manage spikes in traffic and prevent them
- Reduces user request response time
- Make sure that both virtual and physical computing resources perform and are reliable
- Enhances computing environments’ resilience and redundancy
There are two general types of load balancers:
1. Layer 4 load balancing
Load balancers at Layer 4 (L4) work at the transport level. In other words, they can route packets based on the ports they use along with the source and destination IP addresses. In L4 load balancers, Network Address Translation is performed, but each packet is not examined.
2. Layer 7 load balancing
In the OSI model, Layer 7 (L7) load balancers act at the application level. They consider TCP headers, SSL session IDs, and HTTP headers when deciding how to distribute requests across the server farm than their L4 counterparts.
Load balancing algorithm
Load balancers, or the ADC that includes them, use algorithms to distribute requests across the server farm. This is an area where there are many options, ranging from the relatively simple to the extremely complex.
The round robin algorithm ensures that each request from a virtual server is handled by a different server based on a rotating list. Load balancers are easy to implement, but fail to consider the load already on a server. An overloaded server may receive many requests that are processor-intensive.
Least Connection Method
Unlike round-robin, the least connections consider the current load on a server (only its position in the rotation), so they deliver superior performance. Requests will be sent to the virtual server with the smallest number of active connections if using the least connection method.
Least Response Time Method
It is an advanced method that seeks to reduce the response time to a health monitoring request by examining the time it takes the health monitoring server to respond. Indicators of server load and overall user experience include the speed of the response. Load balancers may also consider the number of active connections on each server.
Least Bandwidth Method
The least bandwidth method finds the server with the least amount of traffic, measured in megabits per second (Mbps).
Method of least packets
A service receiving the fewest packets over a given period of time is selected by the least packets method.
This category of methods uses a hash of various packet data to make decisions. During the connection or header phase, this also includes source and destination IP addresses, port numbers, URLs and domain names from the incoming packet.
Custom Load Method
Load balancers can access individual servers’ load records via SNMP by using custom load methods. Server loads can be defined by administrators — CPU utilization, memory, and response time — and then combined based on their needs.
Benefits of load balancing
Optimizing resource usage, data delivery, and response time, load balancing allows high-traffic websites, applications, and databases to be managed. High-traffic environments run smoothly and accurately due to load balancing. The user doesn’t have to deal with unresponsive applications.
It also helps to simplify security, reducing the likelihood of downtime for your business and lost productivity.
Other benefits of load balancing include the following:
- Flexibility: Furthermore, load balancing provides the flexibility of adding and removing servers according to demand. In addition, the traffic is routed to another server during maintenance, so server maintenance can be performed without affecting users.
- Scalability: Traffic increases can negatively affect the performance of an application or website as it is used more often. Load balancing gives you the flexibility to add physical or virtual servers without disrupting current services. Load balancers seamlessly involve new servers in the process as soon as they go online. An overloaded server can be upgraded without much downtime, versus moving a website to a different one.
- Redundancy: Load balancing provides built-in redundancy through the distribution of traffic among servers. Users will experience minimal impact from rerouting the load if a server fails.
Cloud load balancing
Cloud load balancers distribute computing resources and workloads across the cloud. Managing resource demands across multiple computers, networks, or servers is made possible with IT sharing.
Cloud load balancers can help enterprises increase performance and lower costs. Load balancing in the cloud helps reroute workloads more efficiently and improves overall availability. Besides workload and traffic distribution, cloud load balancing systems can monitor cloud applications.
These services are offered by Amazon Web Services (AWS), Google, Microsoft Azure, and Rackspace. You can distribute workloads and traffic across EC2 instances using Elastic Load Balancing. Load balancing is available on the Google Cloud Platform, Google Compute Engine, which distributes network traffic between VM instances. Traffic Manager distributes Azure’s cloud traffic across multiple data centers. Several Rackspace servers distribute workloads through cloud load balancers.
Large companies with applications requiring high performance and availability are likely to use cloud load balancing, but any business can benefit from the technology.
What is container load balancing ?
A container load balancer makes container traffic management easier and more efficient. Continuous integration and continuous delivery (CI / CD) help developers quickly test, deploy, and scale applications. Due to their stateless and transient nature, container-based applications require different traffic control.
How does container load balancing work?
An application can run in containers using the Docker platform. Containers are used to package, distribute, and manage independent applications.
The following steps are necessary:
- Containers deploying across multiple servers.
- Updating continuously and uninterrupted.
- Multi-container load balancing on a single host accessed via the same port.
- Container communication must be secure.
- Container and cluster monitoring.
What Are The Benefits of Container Load Balancing
- Balanced distribution — An algorithm that lets users define how traffic is to be distributed to endpoint groups is a non-weighted round-robin approach
- Accurate health checks — Direct health checks of pods are more accurate than indirect checks.
- Better visibility and security — Pods and containers can be visualized on a granular level based on what information is needed. It is possible to track traffic sources by preserving the IP source.