Auto Scaling Groups (ASG) Flashcards
In which 3 ways can automatic scaling occur?
- Capacity Settings
How many EC2 instances should at least be running - Health Check Replacements
Types: EC2 or ELB (through a ping) - Scaling Policies
1. Target tracking scaling policies (metrics and target)
2. Simple scaling policies (When an alarm is breached) (Is a legacy policy, please don’t use it anymore)
3. Scaling policy with steps
What is a target tracking scaling policy?
A specific manually set metric that acts as a trigger
With target tracking, you select a load metric for your application, such as “Average CPU Utilization” or the new “Request Count Per Target” metric from Application Load Balancer, set the target value, and Auto Scaling adjusts the number of EC2 instances in your Auto Scaling group as needed to maintain that target.
What can we use to automate scaling?
One word
Alarms
Scaling Out means…
Adding more instances
Scaling is triggered when…
An alarm is breached
Which type of load balancer is associated directly to an ASG?
Classic Load Balancer
There are:
- Network Load Balancer
- Classic Load Balancer
- Application Load Balancer
How would you associate an application load balancer with an ASG?
Using a Target Group
in ASG, What is a launch configuration?
It’s a _ that an _ uses to _ _ _
It is a template that an ASG uses to launch EC2 instances.
When you create a launch configuration, you specify information for the instances such as the ID of the Amazon Machine Image (AMI), the instance type, a key pair, one or more security groups, and a block device mapping.
However, you can only specify one launch configuration for an EC2 Auto Scaling group at a time, and you can’t modify a launch configuration after you’ve created it.
Therefore, if you want to change the launch configuration for your EC2 Auto Scaling group, you must create a launch configuration and then update your EC2 Auto Scaling group with the new launch configuration. When you change the launch configuration for your EC2 Auto Scaling group, any new instances are launched using the new configuration parameters, but existing instances are not affected
in ASG, Launch Configurations with versioning are called
Launch Templates
in ASG, To edit a launch configuration you must…
Create a new configuration or clone an existing one
What is the new version of Simple Scaling policy?
Scaling Policy with Steps
It allows you to create steps based on escalation alarm values
What is an ASG?
What are its 3 components?
- It contains a collection of EC2 instances that dynamic scales
- Scaling Policies (Simple, with steps, target tracking)
- Ways to scale (Capacity Settings, Scaling Policies…)
- Launch configurations (Configuration template)
