# AWS Certified Solutions Architect - Associate (Serverless)

###### tags: `AWS`

### Lambda
AWS lambda is a compute service where you can upload your code and create a Lambda function.
- Data centres
- Hardware
- Assembly Code/Protocols
- High Level Languages
- Operating Systems
- Application Layer/AWS APIs
- AWS Lambda

#### Following ways
- Event-driven
- Run your code in response to HTTP requests using Amazon API Gateway



#### Traditional vs Serverless Architecture

#### Language support
- Node.js
- Java
- Python
- C#
- Go
- PowerShell

#### Pricing
- Number of requests
- Duration

Tips:
- Lambda scales out automatically
- Lambda functions are independent, 1 event = 1 function
- Lambda is serverless
- Know what services are serverless
- Lambda functions can trigger other lambda functions, 1 event can = x functions trigger other functions
- Architectures can get extremely complicated, AWS X-ray allows you to debug what is happening
- Lambda can do things globally, you can use it to backup S3 buckets to other S3 buckets etc
- Know your triggers (RDS can not trigger lambda)

### Overview of our serverless website


### Serverless Apllication Model(SAM)
- CloudFormation extension optimized for serverless applications
- New types:
- functions
- APIs
- tables
- Supports anything CloudFormation supports
- Run serverless applicaitons locally
- Package and deploy using CodeDeploy


sam init
sam build
sam deploy --guided

### Elastic Container Service (ECS)
#### What are containers and docker
- A container is a package that contains an application, libraries, runtime, and tools required to run it
- Run on a conrtainer engine like **Docker**
- Provides the **isolation** benefits of virtualization with less overhead and faster starts than VMs
- Containerized applications are **portable** and offer a consistent environment.

#### Components
- Cluster
Logical collection of ECS resources - either ECS EC2 instances or Fargete instances.
- Task Definition
Define your application. Similar to a Dockerfile but for running containers in ECS.
- Container Definition
Inside a task definition, it defines the individual containers a task uses. Controls CPU and memory allocation and port mappings.
- Task
Single running copy of any containers defined by a task definition
- Service
Allows task definitions to be scaled by adding tasks. Defines min and max values.
- Registry
Storage for container images.

#### Fargate
- **Serverless** container engine
- Eliminates need to provision and manage servers
- Specify and pay for resources per application
- Works with both **ECS** and **EKS**
- Each workload runs in its own kernel
- Isolation and security
- Choose EC2 instead if:
- Compliance requirements
- Require broader customization
- Require GPUs

#### EKS
- Elastic Kubernetes Service
- K8s is **open-source** software that lets you deploy and manage containerized applications at scle
- Same toolset on-premises and in cloud
- Containers are grouped in **pods**
- Like ECS, supports both EC2 and Fargate
- Why use EKS?
- Already using K8s
- Want to migrate to AWS

#### ECR
- Managed Docker container registry
- Store, managem and deploy images
- Integrated with ECS and EKS
- WOrks with on-premises deployments
- Highly available
- Integrated with **IAM**
- Pay for storage and data transfer

#### ECS + ELB = ❤️
- Distributed traffic evenly across tasks in your service
- Supports ALB, NLB, CLB
- Use ALB to route HTTP/HTTPS (layer 7) traffic
- Use NLB or CLB to route TCP (layer 4) traffic
- Supported by both EC2 and Fargate launch types
- ALB allows:
- Dynamic host port mapping
- Path-based routing
- Priority rules
- ALB is recommended over NLB or CLB
#### ECS Security
#### Diagram of ECS objects and how they relate