Exploring AWS !!
Day 10:
Introduction to Load Balancers:
Load Balancer is a service that uniformly distributes network traffic & workloads across multiple servers or clusters. Load Balancers increase availability and fault tolerance.
Elastic Load Balancer:
load balancing service for AWS deployments.
ELB scales itself as necessary to handle load.
traffic is distributed in multiple AZ.
single point of contact for clients.
Types:
Classic Load Balancer — like traditional load balancing, but virtual devices replace physical hardware.
Network Load Balancer — used for handling sudden and violent site traffic.
Application Load Balancer — identifies specific incoming traffic and directs it to specific resource.
Gateway Load Balancer — used to ensure high availability by routing traffic flows through healthy virtual appliances, and re-routing in case of unhealthy appliances.
Blue/Green Deployments with Weighted Routes:
with weighted routing we can switch traffic between the versions of our application. This configuration allows us to control distribution of traffic to our application.
Example: If we define a rule having two target groups with weights 8 and 2, load balancer will route 80% traffic to first target group and 20% to another target group.
Classic Load Balancer:
distributes the incoming application traffic across EC2 instance in multiple AZs and functions at layer 7 of OSI model.
routes traffic to healthy instances only, and it is evenly distributed over.
Internet and internal facing load balancer.
Network Load Balancer:
functions at 4th layer of OSI model, flow hash algorithm.
handles millions of requests per second and maintains low latency.
ideal for load balancing TCP/UDP traffic and supports elastic or static IP.
Application Load Balancer:
functions at 7th layer of OSI model, round robin algorithm.
identifies incoming resource type and directs it to appropriate servers.
ideal for load balancing Http/Https traffic.
Cross Zone Load Balancing (CLB):
by default, CLB nodes distribute traffic to instances in their availability zone only.
we enable cross zone load balancing to route evenly across EC2 instances.
ELB routes each request to instance with smallest load.
