HA ASGs

Question 1

What are the 3 ASG components?

Answer 1

1. Groups - Logical component. Webserver group or Application group, DB group, etc.
2. Configuration Templates - Group uses a launch template or launch config as a config template for it’s EC2 instances. You can specify info such as AMI ID, Instance Type, Key Pair, Security Groups, and Block Device mapping for your instances.
3. Scaling Options - provide several ways for you to scale your ASGs. For example, you can config a group to scale based on the occurrences of specified conditions (dynamic scaling) or on a schedule.

Question 2

What are the elements of an ASG Configuration Template?

Answer 2

You can specify info such…

1. AMI ID
2. Instance Type
3. Key Pair
4. Security Groups
5. Block Device mapping for your instances

Question 3

Name the 5 scaling options.

Answer 3

1. Maintain current instance levels at all times
2. Scale manually
3. Scale based on schedule
4. Scale based on demand
5. Predictive Scaling

Question 4

Describe the scaling option… Maintain current instance levels at all times

Answer 4

You can configure your Auto Scaling group to maintain a specified number of running instances at all times. To maintain the current instance levels, Amazon EC2 Auto Scaling performs a periodic health check on running instances within an Auto Scaling group. When Amazon EC2 Auto Scaling finds an unhealthy instance, it terminates that instance and launches a new one.

Question 5

Describe the scaling option… Scale manually

Answer 5

Manual scaling is the most basic way to scale your resources, where you specify only the change in the maximum, minimum, or desired capacity of your Auto Scaling group. Amazon EC2 Auto Scaling manages the process of creating or terminating instances to maintain the updated capacity.

Question 6

Describe the scaling option… Scale based on schedule

Answer 6

Scaling by schedule means that scaling actions are performed automatically as a function of time and date. This is useful when you know exactly when to increase or decrease the number of instances in your group, simply because the need arises on a predictable schedule.

Question 7

Describe the scaling option… Scale based on demand

Answer 7

A more advanced way to scale your resources, using scaling policies, lets you define parameters that control the scaling process. For example, let’s say that you have a web application that currently runs on two instances and you want the CPU utilization of the Auto Scaling group to stay at around 50 percent when the load on the application changes. This method is useful for scaling in response to changing conditions, when you don’t know when those conditions will change. You can set up Amazon EC2 Auto Scaling to respond for you.

Question 8

Describe the scaling option… Scale using Predictive scaling

Answer 8

You can also use Amazon EC2 Auto Scaling in combination with AWS Auto Scaling to scale resources across multiple services. AWS Auto Scaling can help you maintain optimal availability and performance by combining predictive scaling and dynamic scaling (proactive and reactive approaches, respectively) to scale your Amazon EC2 capacity faster.