Please enable JavaScript.
Coggle requires JavaScript to display documents.
AWS-7.ELB & ASG - Coggle Diagram
AWS-7.ELB & ASG
-
-
Load Balancing
Definition
• Load balancers are servers that forward internet traffic to multiple servers (EC2 Instances) downstream.
Why use?
• Spread load across multiple downstream instances
• Expose a single point of access (DNS) to your application
• Seamlessly handle failures of downstream instances (by redirecting to healthy ones)
• Do regular health checks to your instances
• Provide SSL termination (HTTPS) for your websites
• High availability across zones
Elastic Load Balancer
Definition
• An ELB (Elastic Load Balancer) is a managed load balancer
..... AWS guarantees that it will be working
..... AWS takes care of upgrades, maintenance, high availability
..... AWS provides only a few configuration knobs
• It costs less to setup your own load balancer but it will be a lot more effort on your end (maintenance, integrations)
Types
• Application Load Balancer (HTTP / HTTPS only) – Layer 7
• Network Load Balancer (ultra-high performance, allows for TCP) – Layer 4
• Classic Load Balancer (slowly retiring) – Layer 4 & 7
Auto Scaling Group
Why use?
• In real-life, the load on your websites and application can change
• In the cloud, you can create and get rid of servers very quickly
Goal
• Scale out (add EC2 instances) to match an increased load
• Scale in (remove EC2 instances) to match a decreased load
• Ensure we have a minimum and a maximum number of machines running
• Automatically register new instances to a load balancer
• Replace unhealthy instances
-
Strategies
-
-
Predictive Scaling
• Uses Machine Learning to predict future traffic ahead of time
• Automatically provisions the right number of EC2 instances in advance