Introduction to Load Balancers USE THIS LINK

What is load balancing?

There could be millions of requests arriving per second in a typical data center. To serve these requests, thousands (or hundred thousand) servers will be working together to share the load of incoming requests. A question arises:

Who will divide the incoming requests among all the available servers?

A Load Balancer (LB) is the answer to the question. The load balancing layer is the first point of contact within a data center after the firewall. A load balancer may not be a requirement if your service entertains a few hundred or even a hundred thousand requests per second. However, for increasing clients’ requests load balancers provide the following capabilities:

• Scalability: By adding servers, the capacity of the application/service can be increased seamlessly.
• Availability: Even if some servers go down or suffer a fault, the system will still remain available.
• Performance: Load balancers can forward requests to servers with a lesser load so the user can get a quicker response time.

Here is an abstract depiction of how load balancers work:

Services offered by LBs

LBs not only enable services to be scalable, available, and highly performant, they offer some key services like:

• Health checking: Using the heartbeat protocolThe heartbeat protocol is a way of identifying failures in distributed systems. Using this protocol, every node in a cluster periodically reports its health to a monitoring service., LBs can monitor the health and, therefore, reliability of end-servers. Another advantage of health checking is the improved user experience.

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