AWS Application Load Balancingr -ALB
Application Load Balancingr works at layer 7 (application layer). It allows you to define routing rules based upon content across multiple services and containers running on one or several EC2 instances.
Scales the load balancer when traffic to the application changes.
Automated scaling of large workloads.
Supports health checks, used for monitoring the health of registered targets to ensure that the load balancer can only send requests to healthy targets.
Application Load Balancing ComponentsA load balancing serves as the single point for clients.
.medrectangle-4-multi-340border:none !important;display:block !important;float:none !important;line-height:0px;margin-bottom:15px !important;margin-left:auto !important;margin-right:auto !important;margin-top:15px !important;max-width:100% !important;min-height:250px;min-width:250px;padding:0;text-align:center !important;width:100%;distributes incoming application traffic across multiple targets, such as EC2 instances, in multiple AZs, which increases the availability of the application.
One or more listeners may be added to the load-balancing system.
Listeners check for connections requests from clients using the specified protocol and port
Rules that are defined will determine how the load balancer routes requests to registered targets.
Each rule is composed of a priority, one to three actions, and one or two conditions.
Supported actions areforward
redirect,
fixed-response
Supported rule conditions arehost-header
http-request-method
path-pattern
source-ip
http-header
query-string
When the conditions for a rule have been met, it is executed.
A default rule must be set for each listener. Optionally, additional rules can also be set.
Target grouproutes requests using the specified protocol number and port number to one or more registered targets such as EC2 instances.
Multiple target groups can be registered for a target.
Health checks can be set up per target group.
All targets that are registered to a target group specified in a load balancer listener rule are subject to health checks.
Target group supports EC2 instances (can also be managed as part of the ASG).
ECS tasks
Lambda functions
Private IP addresses on AWS or On Premises via VPN or DX
Supports weighted target group routing allows routing traffic forwarded by a rule towards multiple target groups.
This allows for use cases such as blue-green, canary, and hybrid deployments without the necessity of multiple load balancers.
It also allows zero downtime migration between cloud and on-premises compute types.
You can configure listener rules to route requests to different target audiences based on the content and application traffic.
Routing is done independently for each target group, even if a target is registered with multiple targets.
The routing algorithm can be set up at the level of the target group.
Round-robin default routing algorithm; alternatively, the least outgoing requests routing algorithm can also been specified.
Refer Blog Post @ Classic Load Balancer vs Application Load Balancer vs Network Load Balancer
Application Load Balancer Benefits
Support for Path-based routing. Listener rules can be set up to forward requests based upon the URL in the request. This allows you to structure applications as microservices (microservices) and route requests to the right service based upon the URL content.
Dynamic Port mapping allows you to route requests to multiple services from one EC2 instance.
Support for containerized applications EC2 Containe
