# Module 6: Compute

# Section 1: Compute services overview
## AWS compute services
* Amazon EC2:
* resizable virtual machine
* Amazon EC2 auto-scaling:
* define conditions to launch or terminate EC2 instances
* Amazon ECR:
* store and retrieve Docker images
* Amazon ECS:
* Container orchestration service that supports Docker
* VMWare Cloud on AWS:
* hybrid cloud without custom hardware
* AWS Elastic Beanstalk:
* run and manage web app
* AWS Lambda:
* serverless compute solution
* Amazon EKS:
* run managed kubernetes on AWS
* Amazon LightSail:
* building app or website
* AWS Batch:
* running batch job at any scale
* AWS Fargate:
* run containers
* AWS Outpost:
* run AWS services in your on-premises data center
* AWS Serverless Repository:
* discover, deploy and publish application

## Categorizing compute services

## Choosing the optimal compute service
* The optimal compute service or services that you use will depend on your use case
* Some aspects to consider
* What is your application design ?
* What are your usage pattern ?
* Which configuration settings wll you want to manage ?
* Selecting the wrong compute solution for an architecture can lead to lower performance efficiency
* A good starting place: understand the available compute options

# Section 2: Amazon EC2
## Amazon Elastic Compute Cloud (Amazon EC2)
Example uses of Amazon EC2 instances:
* App server
* web server
* Database server
* Game server
* Mail server
* Media server
* Catalog server
* File server
* Computing server
* Proxy server

## Amazon EC2 overview
* Amazon Elastic Compute Cloud (Amazon EC2)
* Provides *virtual machines* (EC2 instance) in the cloud
* Fives you *full control* over the guest operating system (Windows or Linux) on each instance
* You can launch instances of any size into and Availability Zone anywhere in the world
* Launch instance from **Amazon Machine Images (AMIs)**
* Launch instances with a few clicks or a line of code, and they are ready in minutes
* You can control traffic to and from instances

## Launching an amazon EC2 instance

:::danger
Nine key decisions when creating a EC2 instance.
:::
### 1. Select an AMI
* Amazon Machine Image (AMI)
* Is a template that is used to create an EC2 instance
* Contains a *Windows* or *Linux* OS
* Often has some software pre-installed
* AMI choices:
* Quick Start
* Linux and Windows AMIs provided by AWS
* My AMIs
* Any AMIs that you created
* AWS Marketplace
* Pre-configured templates from third parties
* Community AMIs
* AMIs shared by others; use at you own risk


## 2. Select an instance type
* Consider you use case
* How will the EC2 instance you create be used ?
* The **instance type** that you choose determines
* Memory (RAM)
* Processing power (CPU)
* Disk space and disk type (Storage)
* Network performance
* Instance type categories
* General purpose
* Compute optimized
* Memory optimized
* Storage optimized
* Accelerated computed
* Instance types offer *family, generation* and *size*

### Instance type naming and sizes

### Based on use case

### Networking features
* The network bandwith (GBps) varies by instance type
* To maximize networking and bandwith performance of your instance type
* If you have interdependent instances, launch them into a *cluster placement group*
* Enable enhanced networking
* Enhanced networking types are supported on most instance types
* Enhanced networking types
* Elastic Network Adapter (ENA): Supports network speeds of up to 100 Gpbds
* Intel 82599 Virtual Function interface: Supports network speeds of up to 10 Gbps

# Section 3: Amazon EC2 Part 2
## 3. Specify network settings
* Where should the instance be deployed ?
* Identify the VPC and optinally the **subnet**
* Should a *public IP address* be automatically assigned ?
* To make it internet-accessible


## 4. Attach IAM role (optional)
* Will software on the EC2 insrance need to interact with other AWS services ?
* If yes, attach an appropriate IAM Role
* An AWS Identity and Access Management (IAM) role that is attache to an EC2 instance is kept in an **instance profile**
* You are *not* restricted to attaching a role only at instance launch
* You can also attach a role to an instance that already exists

## 5. User data script (optional)
* Optionally specify a user data script at instance launch
* Use **user data** scripts to customize the runtime environment of your instance
* Script executes the first time the instance starts
* Can be used strategically
* Reduce the number of custom AMIs that you build and maintain


## 6. Specify storage
* Configure the *root volume*
* Where the guest operating system is installed
* Attach *additional storage volumes* (optional)
* AMI might already include more than one volume
* For each volume, specify:
* The *size* of the disk (in GB)
* The *volume type*
* Different types of SSDs and HDDs are available
* If the volume will be deleted when the instance is terminated
* If *encryption* should be used

### Amazon EC2 storage options
* **Amazon Elastic Block Store (Amazon EBS)**
* *Durable*, block-level storage volumes
* You can stop the instance and start it again, and the data will still be there
* **Amazon Elastic Block Store**
* Storage is provided on disls that are attached to the host computer where the EC2 instance is running
* *If the instance stops, data stored here is deleted*
* Other options for storage (not for root volume)
* Mount an **Amazon Elastic File System (Amazon EFS)** file system
* Connect to **Amazon Simple Storage Service (Amazon S3)**

### Example storage options

* **Instance 1** characteristics
* It has an **Amazon EBS** *root volume* type for the operating system
* What will happen if the instance is stopped and then started again ?
* The OS volume would survive
* Any data stored on Amazon EBS would remain intact
* Any data stored in ephemeral volume 1 would be lost
* **Instance 2** characteristics
* It has an **Instance Store** *root volume* type for the operating system
* What will happen if the instance stops (because of user error or a system malfunction)?
* All data stored in ephemeral volume 2 would be lost, including the OS

# Section 4: Amazon EC2 Part 3
## 7. Add tags
:::info
A **tag** is a label that you can assign to an AWS resource
* Consists of a *key* and an optional *value*
:::
* Tagging is how you can attach **metadata** to an EC2 instance
* Potential benefits from tagging - Filtering, automation, cost allocation and access control

## 8. Security group settings
:::info
A **security group** is a *set of firewall rules* that control traffic to the instance.
* It exsists *outside* of the instance's guest OS
:::

Create **rules** that specify the **source** and which **ports** that network communications can use.
* Specify the **port** number and the **protocol**, such as TCP, UDP or ICMP
* Specify the **source** that is allowed to use the rule

## 9. Identify the key pair
* At instance launch, you specify an existing key pair *or* create a new key pair
* A **key pair** consists of
* A *public key* that AWS stores
* A *private key* file that you store
* It enables secure connections to the instance
* For **Windows AMIs**
* Use the private key to obtain the administrator password that you need to log in to your instance
* For **Linux AMIs**
* Use the private key to use SSH to securely connect to your instance

## Amazon EC2 console view of a running EC2 instance

## Another option: Launch an EC2 instance with the AWS CLI
* EC2 instances can also be created programmatically

aws ec2 run-instances --image0id ami-1a2b3c4d --count 1 --instance-type c3.large \
--key-name MyKeyPair --security-groups MySecurityGroup --region us-east-1

This example shows how simple the command can be.
* This command assumes that the key pair and security group already exists
* More option could be specified

## Amazon EC2 instance lifecycle

## Consider using an Elastic IP address
* **Rebooting** an instanc will *not* change any IP addresses or DNS hostnames
* When an instance will *not* change any IP addresses or DNS hostnames
* When an instance is **stopped** and then **started** again
* The *public* IPv4 address and *external* DNS hostname will change
* The *private* IPv4 address and internal DNS hostname do *not* change
* If you require a persistent public IP address
* Associate an *Elastic IP address* with the instance
* Elastic IP address characteristics
* Can be associated with instances in the Region as needed
* Remains allocated to your account until you choose to release it

## EC2 instance metadata
:::info
It is data about your instance
:::
* While you are connected to the instance, you can view it
* In a browser: `http://169.254.169.254/latest/meta-data/`
* In a terminal window: `curl http://169.254.169.254/latest/meta-data/`
* Example retrievable values
* Public IP address, private IP address, public hostname, instance ID, security groups, Region, Availability zone
* Any user data specified at instance launch can also be accesse at: `http://169.254.169.254/latest/user-data/`
* It can be used to configure or manage a running instance
* For example, author a configuration script that read the metadata and uses to configure applications or OS settings

## Amazon CloudWatch for monitoring
* Use **Amazon CloudWatch** to monitor EC2 instances
* Provides near-real-time metrics
* Provides charts in the Amazon EC2 console **Monitoring** tab
* Maintains 15 months of historical data
* **Basic monitoring**
* Default, no additional cost
* Metric data sent to CloudWatch every 5 minutes
* **Detailed monitoring**
* Fixed monthly rate for seven pre-selected metrics
* Metric data delivered every 1 min

# Section 5: Amazon EC2 Cost Optimization
## Amazon EC2 pricing models
* **On-Demand Instances**
* Pay by the hour
* No long-term commitments
* Elligible for the AWS Free Tier
* **Dedicated Hosts**
* A physical server with EC2 instance capacity fully dedicated to your use
* **Dedicated instances**
* Instances that run in a VPC on a hardware that is dedicated to a single customer
* **Reserverd Instances**
* Full, partial, or no upfront payment for instance you reserve
* Discount on hourly charge for that instance
* 1-year or 3-year term
* **Scheduled Reserverd Instances**
* Purchase a capacity reservation that is always available on a recurring schedule you specify
* 1-year term
* **Spot Instances**
* Instances run as long as they are available and your bid is above the Spot Instance price
* They can be interrupted by AWS with a 2-minute notification
* Interruption options include terminated, stopped or hibernated
* Prices can be significantly less expensive compared to On-Demand Instances
* Good choice when you have flexibility in when your applications can run

### Benefits
|On-Demand Instances|Spot Instances|Reserved Instances|Dedicated Hosts|
|-|-|-|-|
|Low cost and flexibility|Large scale, dynamic workload|Predictability ensures compute capacity is available when needed|Save money on licensing costs </br> Help meet compliance and regulatory requirements|

### Use cases

## The 4 pillars of cost optimization

### Pillar 1: Right size
* Provision instances to match the need
* CPU, memory, storage and network throughput
* Selct appropriate *instance types* for your use
* Use Amazon CloudWatch metrics
* How idle are instances? When
* Downsizze instances
* Best practice: right size, then reserve

### Pillar 2: Increase elasticity
* **Stop** or **hibernate** amazon EBS-backed instances that are not actively in use
* Example: non-production development or test instances
* Use **automatic scaling** to match needs base on usage
* Automated and time-based elasticity

### Pillar 3: Optimal pricing model
* Leverage the right pricing model for your use case
* Consider your usage patterns
* Optimize and *combine* purchase types
* Examples:
* Use *On-Demand Instance* and *Spot Instances* for variable workloads
* Use *Reserved Instances* for predictable workloads
* Consider serverless solutions (AWS Lambda)

### Pillar 4: Optimize storage choices
* Reduce cost while maintaining storage performance and availability
* Resixe EBS volumes
* Changes EBS volumes types
* Can you meet performance requirements with less expensive storage ?
* Example: *Amazon EBS Throughput Optimized HDD (st1)* storage typically costs half as much as the default *General Purpose SSD (gp2)* storage option
* Delete EBS snapshots that are no longer needed
* Identify the most appropriate destination for specific types of data
* Does the app need the instance to reside on Amazon EBS ?
* Amazon S3 storage options with lifecycle policies can reduce costs

## Measure, monitor and improve
* Cost optimization is an ongoing process
* Recommendations
* Define and enforce *cost allocation tagging*
* Define metrics, set targets, and review regularly
* Encourage teams to *architect for cost*
* Assign the responsibility of optimization to an individual or to a team

# Section 6: Container services
## Container basics
:::info
**Containers** are a method of *operating system virtualization*
:::

Benefits:
* Repeatable
* Self-contained environments
* Software runs the same in different environments
* Developer's laptop, test, prod
* Faster to launch and stop or terminate than virtual machines

## What is Docker ?
:::info
**Docker** is a software platform that enables you to build, test, and deploy app quickly.
:::
* You run containers on Docker
* Containers are created from a template called an *image*
* A **container** has everything a software app needs to run

## Containers vs VMs

## Amazon Elastic Container Service (Amazon ECS)
:::info
A highly scalable, fast, **container management service**.
:::
* Key benefit
* Ocherstartes the running of Docker containers
* Maintains and scales the fleet of nodes that run your containers
* Removes the complexity of standing up the infrastucture
* Integrated with features that are familiar to Amazon EC2 service users
* Elastic Load Balancing
* Amazon EC2 security groups
* Amazon EBS volumes
* IAM roles

## Amazon ECS orchestrates containers

## Amazon ECS cluster options
***Do you want to manage the Amazon ECS cluster that runs the containers ?***
* Yes: create an **Amazon ECS cluster backed by Amazon EC2**
* Provides more granular control over infrastructure
* No: create an **Amazon ECS cluster back by AWS Fargate**
* Easier to maintain, focus on your app


## What is Kubernetes ?
* Kubernetes is open source software for containers orchestration
* deploy and **manage containerized app** *at scale*
* The same toolset can be used on premises and in the cloud
* Complements Docker
* Docker enables you to run mutliple containers on a single OS host
* Kubernetes **orchestrates** mutliple Docker hosts (nodes)
* Automates
* Container provisioning
* Networking
* Load distribution
* Scaling

## Amazon Elastic Kubernetes Service (Amazon EKS)
* EKS
* Enables you to run Kubernetes on AWS
* Certified Kubernetes conformant
* Supports Linux and Windows containers
* Compatible with Kubernetes community tools and add-ons
* Use Amazon EKS to
* Manage clusters of Amazon EC2 instances
* Run containers that ar ochestrated by Kubernetes on those instances

## Amazon Elastic Container Registry (Amazon ECR)
:::info
**Amazon ECR** is a fully managed Docker *container registry* that makes it easy for developpers to store, manage and deploy Docker container images.
:::
* Supports
* Team collab
* Acces control
* Third party integration
* Possible to use with Amazon EKS

# Section 7: Introduction to AWS Lambda
## AWS Lambda: Run code without servers
:::info
AWS Lambda is a **serverless** compute service.
:::

## Benefits of Lambda
* Supports multiple programming languages
* Completely automated administration
* Built-in fault tolerance
* Supports orchestration of multiple functions
* Pay-per-use pricing

## AWS Lambda event sources

## AWS Lambda function configuration
* Create lambda function: give a name
* Runtime environment
* Python
* Node.js
* Execution role to grant IAM permission to the function to interact with other services
* Configure the function
* adding a trigger
* Add function code
* Specify the memory in megabytes (up to 3008MGB)
* Specify env variable


## Schedule-based Lambda function example: start and stop EC2 instances

## Envent-based Lambda function example: create thumbnail images

## AWS Lambda limits
Soft limits per Region
* Concurrent executions = 1,000
* Function and layer storage = 75GB

Hard limits for individual function:
* Max function memory alloc = 3,008 MB
* Function tiemout = 15 min
* Deployement package size = 250 MB unzipped, including layers

# Section 8: Introduction to AWS Elastic Beanstalk
## AWS Elastic Beanstalk
* An easy way to get *web app* up and running
* A *managed service* that automatically handles
* Infra provisionning and config
* Deployement
* Load balancing
* Automatic scaling
* Health monitoring
* Analysis and debugging
* Logging
* No additional charge for Elastic Beanstalk
* Pay only for the underlying ressources that are used

## AWS Elastic Beanstalk deployements
* Supports web app written for common platforms
* Java, .NET, PHP, Node.js, Python, Ruby, Go and Docker
* You upload your code
* Elastic Beanstalk automatically handles the deployement
* Deploys on servers such as Apache, NGINX, Passenger, Puma, and Microsoft Internet Information Services (IIS)

## Benefits of Elastic Beanstalk

# Wrap-up
Which AWS service helps developers quickly deploy resources which can make use of different programming languages, such as .Net and Java ?
1. AWS CloudFormation
2. AWS SQS
3. AWS Elastic Beanstalk
4. Amazon Elastic Compute Cloud (Amazon EC2)

:::spoiler Answer
Keywords:
* developers quickly deploy resources
* different programming languages

Answer 3.
:::