mediumSystem Design

What is a load balancer and what strategies does it use?

Q: What is a load balancer and what strategies does it use?

## What a load balancer does A load balancer (LB) sits in front of a pool of servers and **spreads incoming requests** across them so no single server is overwhelmed. It also delivers **high availability**: it health-checks backends and stops routing to unhealthy ones. Clients Load balancer <rect class='d-box' x='374' y='88

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Explain load balancing.

load-balancing

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Round-robin selection

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import itertools

class RoundRobin:
    def __init__(self, servers):
        self.servers = servers
        self._cycle = itertools.cycle(servers)
    def next(self):
        return next(self._cycle)

lb = RoundRobin(["s1", "s2", "s3"])
for _ in range(7):
    print("route ->", lb.next())

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