# Module 10: Automatic Scaling and Monitoring

# Section 1: Load Balancing
:::info
* Distributes incoming app or network traffic across multiple targets in a single or multiples AZ
* Scales your load balance as traffic to your aapp changes over time

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## Types of loads balancers

## How Elastic Loas Balancing works
* With Application Load Balncers and Network Load Balancers, you **register targets in traffic to the target groups**
* With Classic Load Balancers, you *register instance with the load balancer*
* Load balancer performs health checks to monitor health of registered targets


## Elastic Load Balancing use cases
* High available and fault-tolerant app
* Containerized app
* Elasticity and scalability
* VPC
* Hybrid environments
* Incoke Lambad functions over HTTP(S)

## Load balancer monitoring
* **Amazon CloudWatch metrics**
* Used to verify that the system is performing as expected and creates an alarm to initiate an action if a metric goes outside an acceptable range
* **Access logs**
* Capture detailed information about requests sent to your load balancer
* **AWS CloudTrail logs**
* Capture the who, what, when, and where of API interactions in AWS services

# Section 2: Amazon CloudWatch
## Monitoring AWS resources
To use AWS efficiently, you need insight into your AWS resources:
* How do you know when you should *launch more Amazon EC2 instances ?*
* Is your *app's performance or availability* being affected by a lack of sufficient capacity ?
* How much of your infrastructure is actually *being used* ?

## Amazon CloudWatch
* Monitors
* AWS resources
* App that run on AWS
* Collect and track
* Standard metrics
* Custom metrics
* Alarms
* Send notifications to an Amazon SNS topic
* Perform Amazon EC2 Auto Scaling or Amazon EC2 actions
* Events
* Define rules to match changes in AWS environment and route these events to one or more target functions or streams for processing

## CloudWatch alarsm
* Create alarms basde on
* Static threshold
* Anomlay detection
* Metric math expression
* Specify
* Namespace
* Metric
* Statistic
* Period
* Conditions
* Additional configuration
* Actions


# Section 3: Amazon EC2 Auto Scaling
## Why is scaling important ?
:::info
Scaling is the ability ot increase of decrease the compute capacity of your app.
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* First graph: unused capacity on most days of the week, not cost optimized
* Second graph: under capacity on certain days

:::warning
Automatic capacity scaling is necessary to support the fluctuating demands for service.
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## Amazon EC2 Auto Scaling
* Hels you maintaint app
* Enables you to automatically add or remove EC2 instances according to conditions taht you define
* Detects impaired EC2 instances and unhealthy app, and replaces the instances without your intervention
* Provides several scaling options
* Manual
* Scheduled
* Dynamic (on-demand)
* Predictive


## Typical weekly traffic at Amazon.com

## November traffic to Amazon.com

## Auto Scaling groups
:::info
An **Auto Scaling group** is a collection of EC2 instances that are treated as a logical grouping for the purposes of automatic scaling and management.
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## Scaling ou vs scaling in

## How Amazon EC2 Auto Scaling works

## Implementing dynamic scaling

## AWS Auto Scaling
* Monitors you app and automatically adjusts capacity to maintain steady, predictable performance at the lowest possible cost
* Provides a simple, powerful user interface that enables you to build scaling plans for resources, including
* Amazon EC2 instances and Spot Fleet
* Amazon Elastic Container Service (Amazon ECS) Tasks
* Amazon DynamoDB tables and indexes
* Amazon Aurora Replicas

# Wrap-up
Which service would you sue to send alerts base on Amazon CloudWatch alarms ?
1. Amazon Simple Notification Service
2. AWS CloudTrail
3. AWS Trusted Advisor
4. Amazon Route 53

:::spoiler Answer
Keywords:
* send alerts
* Amazon CloudWatch Alarms

Answer: 1.
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