Kubernetes Load Balancing: Configuration, Components & More

The container orchestration technology Kubernetes is a blessing in the Microservices context. In conclusion, many companies are using microservices to handle projects. In other words, businesses now have to manage hundreds of tiny containers on different platforms. Data loads have the potential to significantly slow down network performance if they are not properly handled and balanced. Additionally, end users would have fewer resources available to them to run containers and virtual machines if data balancing is not done. But when scalability and availability are properly managed, bottlenecks and resource constraints become unimportant. You must employ load balancing in order to use Kubernetes effectively. Users are spared the annoyance of dealing with sluggish services and applications thanks to Kubernetes load balancing. Additionally, it serves as an imperceptible middleman between a client and a collection of servers, preventing lost connection requests. 

What is Kubernetes Load Balancing?

Kubernetes Load balancing is a key tactic for enhancing availability and scalability because it effectively divides network traffic among numerous backend services. In the Kubernetes environment, there are several solutions for load balancing external traffic to pods, each having advantages and disadvantages of its own. 

The most fundamental form of load balancing in Kubernetes is load distribution. Implementing load distribution is simple at the dispatch level. The kube-proxy feature is used by both of the load distribution strategies that are supported by Kubernetes. The virtual IPs that are managed by the kube-proxy feature are used by services in Kubernetes. 

Servers can be found in a data center, the cloud, or on-premises. They could be physical, virtual, or a component of hybrid solutions. Therefore, load balancing must function across a wide range of platforms. You need to produce the most with the quickest response time in all circumstances. 

So, basically what is load balancer in Kubernetes?  

The load balancer automatically reroutes traffic in the event that a server does go offline for some reason. The load balancer allocates a new server's resources on your behalf when you add it to the server pool. Automatic load balancers make sure your system maintains high availability throughout upgrades and other system maintenance procedures in order to achieve this. You can also enroll in Docker Kubernetes Certification  and brush up your skills while earning certification with this certification course  

Components of Kubernetes Load Balancing

1. Pods and Containers

Linux containers are used to package the software that runs on Kubernetes. Since containers are a widely used technology, Kubernetes supports the deployment of numerous pre-built images. 

Linux execution environments that are self-contained can be produced via containerization. Any application can be combined with all of its dependencies into a single file, which can then be distributed over the internet. With very little preparation needed, anyone may download the container and install it on their infrastructure. Programmatic container creation enables the development of strong CI and CD pipelines. 

Although multiple programs can be added to a single container, it is best to keep things to just one process per container. More tiny containers are preferable to one large one. Updates are simpler to deploy, and problems are simpler to identify if each container has a narrow focus. 

Pods are objects made up of a collection of containers. These spaces are used for projects that are directly related to the service they offer. In essence, the purpose of pods is to recreate application-specific environments that accurately reflect use cases. Because of this, pods are ideal for software development because they let teams move swiftly between sites or businesses in dynamic work settings. 

Generally speaking, pods assist in creating a single, unified service building block. Creating Pods for projects is common, and you frequently destroy or achieve them to satisfy business requirements. Pods can be thought of as transient, scalable, adaptable entities that can be moved about as needed. Your created pods each have a unique UID and IP address. These characteristics allow Pod to converse with one another. 

2. Service

Services in Kubernetes are collections of pods with a common name. Services serve as the point of access for outside customers and have consistent IP addresses. Services are designed to distribute traffic to a group of pods, much like traditional load balancers. 

3. Ingress or Ingress Controller

Ingress is a set of routing rules that regulates how people from the outside can access services. Each rule set has the ability to do name-based virtual hosting or routing, SSL termination, and load balancing. Ingress can, in essence, operate at layer 7, which enables it to sniff packets to obtain more data for intelligent routing. A component known as an ingress controller is required for Ingress to work in a Kubernetes cluster. The following are some instances of controllers: NginX, HAProxy, Traefik, etc. In any case, you will need to activate them because they don't start with the cluster.

4. Kubernetes load balancer 

The distributed architecture of a Kubernetes cluster relies on several instances of services because of its fundamental design, which complicates things if load distribution is not careful. To ensure optimal workloads and high availability, load balancers are services that distribute incoming traffic over a pool of hosts. 

As a traffic controller, a Kubernetes load balancer service directs client requests to the nodes that can process them fast and effectively. The load balancer redistributes its duty across the remaining nodes when one host fails. On the other side, the service begins automatically forwarding requests to PODs associated to new nodes when they join a cluster. 

How Does Kubernetes Load Balancer Work?

We must first realize that there are various meanings for "load balancer" in Kubernetes. For the purposes of this blog, we'll concentrate on two tasks: making Kubernetes services accessible to the public and allocating a balanced amount of network traffic to those services.

Nginx.com

Your containers that are connected by function will be arranged into pods using Kubernetes. Then, a service that includes all of your connected pods is created. As needed, Kubernetes will automatically construct and destroy pods because they are not intended to be persistent. Since pods are not durable, their IP addresses are also assigned randomly for each new pod. 

Services (collections of pods), on the other hand, are given a stable ClusterIP that can only be accessed within that Kubernetes cluster. Through the ClusterIP, other Kubernetes containers can then access the pods that make up a service.  

The ClusterIP, however, cannot be accessed from outside the cluster. To manage all requests coming from outside the cluster and route that traffic to the services, you need a load balancer. This function is addressed by the first two load balancers we'll talk about, NodePort and LoadBalancer. 

We'll discuss another type of load balancer that actually balances network traffic. Network traffic is distributed to services by this kind of k8s load balancer in accordance with established routing rules or algorithms. If you also want to innovate faster and explore the secrets of development, then Devops courses will benefit you in many ways.  

How to Configure Load Balancer in Kubernetes?

A load balancer can be added in one of two ways to a Kubernetes cluster: 

Configuration File:

By changing the type field in the service configuration file to LoadBalancer, the load balancer is provided. The cloud service provider controls and manages this load balancer, which routes traffic to back-end PODs. The configuration file for the service should resemble:

--- 
apiVersion: v1 
kind: Service 
metadata: 
 name: darwin-service 
spec: 
 selector: 
app: example 
 ports: 
- port: 8765 
targetPort: 9376 
type: loadBalancer 

Users may be able to assign an IP address to the load balancer depending on the cloud provider. The loadBalancerIP tag given by the user can be used to customize this. If the user does not select one, an ephemeral IP address is assigned to this load balancer. The IP address is disregarded if the user specifies one that the cloud provider does not support. 

The.status.loadBalancer field should contain any additional information the user wants to add to the load balancer service. To set the Ingress IP Address, for instance: 

status: 
 loadBalancer: 
ingress: 
- ip: 192.0.2.127 

Using kubectl:

By supplying the flag —type=loadBalancer with the kubectl expose command, a load balancer can also be created:

kubectl expose pod darwin --port=8765 --target-port=9376 \ 
--name=darwin-service --type=LoadBalancer

The command connects the POD with the name darwin to port 9376 and establishes a new service called darwin. 

In-depth information about Kubernetes load balancing, including its architecture and different provisioning techniques for a Kubernetes cluster, was the goal of this post. 

Load balancing, one of the key responsibilities of a Kubernetes administrator, is essential for sustaining a productive cluster. Tasks can be efficiently scheduled across cluster PODs and nodes using an optimally provided load balancer, ensuring High Availability, Quick Recovery, and Low Latency for containerized applications operating on Kubernetes. 

Strategies of Kubernetes Load Balancing

You must choose how to balance the traffic to your pods if you want to use Kubernetes services to their fullest efficiency and availability. Several well-liked Kubernetes load balancing techniques are: 

1. Round Robin

The round robin method distributes traffic to a list of qualified pods in a specific order. In a round robin arrangement, for instance, if you had five pods, the load balancer would send the first request to pod 1, the second request to pod 2, and so on in a recursive cycle. Since the round robin technique is static, it won't take into consideration factors like the current server load. Round robin is often favored for testing environments rather than for real-world traffic because of this. 

2. Kube-proxy L4 Round Robin Load Balancing

A typical Kubernetes cluster uses the kube-proxy as its most fundamental default load balancing method. All requests made to the Kubernetes service are processed and routed by the kube-proxy.

However, because the kube-proxy is a process and not a proxy, it implements a virtual IP for the service using iptables rules, which complicates the routing and adds to its design. The amount of latency increases with each request, and the number of services increases the severity of this issue.

3. L7 Round Robin Load Balancing

Most of the time, it is crucial to bypass the kube-proxy and direct traffic to Kubernetes pods. To do this, utilize an API Gateway for Kubernetes that divides requests across the available Kubernetes pods using an L7 proxy.

Using the Kubernetes Endpoints API, the load balancer monitors the availability of pods. The Kubernetes load balancer distributes requests to the appropriate Kubernetes pods for a given service when it receives a request for a certain Kubernetes service.

4. Consistent Hashing/Ring Hash

Using a hashing algorithm, the constant hash load balancing technique sends all requests from a specific client or session to the same pod. For Kubernetes services that must maintain per-client state, this is helpful. However, using a consistent hash technique to fairly distribute the load amongst many servers can be difficult because client workloads might not be equal. Additionally, hashing methods' high processing costs at scale can result in some lag.

Benefits of Kubernetes Load Balancing

High availability for your company is one of the numerous value-adding benefits of load balancing. 

1. Support for traffic during peak hours: load balancing offers a high-quality and quick response to demand. Support for traffic during peak hours. 
2. Traffic shifting during canary releases: When new developments are issued as "canaries," traffic is diverted via the network to make up for any resource bottlenecks. 
3. Blue or green releases: Load balancing helps prevent a system-wide delay when you run different versions of an application in two different contexts. 
4. Infrastructure migration: load balancing assists in achieving high availability as platform transfers take place. 
5. Predictive Analysis: Using predictive analytics, routine modifications can be performed proactively to account for changing user traffic as it occurs. 
6. Maintenance task flexibility: By diverting customers to online servers when maintenance takes place, outages are decreased. 

Conclusion

From simple traffic management systems to managing complex systems, load balancing has advanced. Additionally, a company that hosts demanding platforms like Kubernetes can benefit greatly from it. This is so that Kubernetes may allocate dynamic resources across several platforms for projects. 

Maintaining the functionality of your Kubernetes clusters requires load balancing. Above all, keep in mind to tailor your Kubernetes infrastructure to your requirements. That is to say, you are not required to follow the traffic management guidelines by default. When you optimize your system, you'll have a durable solution that is simpler to maintain and has fewer "server downs." 

It's crucial to remember that several of these Kubernetes load balancing techniques come in different flavors that enhance their usefulness. For instance, weighted round robin enables administrators to lower the priority level of weaker pods so they receive fewer requests. The load distribution mechanism you can utilize might be constrained by the approach you take to deal with external requests. 

In order to take advantage of the load distribution method that works best for your applications, it's crucial to select a Kubernetes load balancer strategy that can properly manage external connections in accordance with your specific business requirements. If you’re interested in Kubernetes, our recommendation would be to start with KnowledgeHut’s Docker Kubernetes Certification for building, testing, and deploying Docker applications.