session-38.txt

1. VPC --> Project
	vpc
	subnets --> public, private, database
	igw --> attach to VPC
	route tables --> public, private, database and associations
	eip
	NAT
	routes
	peering
	peering routes
2. SG --> Project infra, SG rules --> app infra
3. VPN
4. DB
5. APP ALB
	listener -> should be listening on particular to accept connections
	rules --> based on rule, it can redirect traffic to different target groups
	target groups --> group of instances belong to particular component/module
	*.app-dev.daws78s.online --> APP ALB
		backend.app-dev.daws78s.online --> backend target group
		user.app-dev.daws78s.online --> user target group
6. ACM certs
7. web ALB

8. backend
		create instance
		configure using null resource, ansible
			install nodejs
			create user and directory
			download and unzip code
			create systemctl service
			install mysql client
			load schema
			start the service, must enable
		stop the instance
		take AMI
		delete the instance
		
		create target group
		create launch template
		create ASG
		create ASG policy
		create listener rule
9. frontend same as above

10. Cloudfront
--------------------------

ISP --> download movies with high speed.

Home --> ISP servers --> download movies from internet and store them in their servers

small website to download movies

users open this website --> click download

high speed download

ISP servers --> cache servers

cache

netflix --> Servers are in US
content servers --> across the globe

mummy --> download movie from US servers --> Indian cache servers

CDN --> content delivery network
edge locations

us-east-1 --> CDN --> edge locations are provided by AWS

images, videos are static content and high memory
code --> dynamic content

https://web-dev.daws78s.online/api/transaction --> backend.app-dev.daws78s.online/transaction

backend.app-dev.daws78s.online --> backend servers

10.0.11.135:8080/transaction

HTTP Methods(Verbs) CRUD
------------------
GET --> requesting for information, read only request (READ)
POST --> Creating information. calling multiple times is unsafe, not idempotent (Create)
PUT -- UPDATE, resources update, safe
DELETE --> Deleting the resources, safe

files are in some source

CDN --> connects to source and fetch the data

/images -> enable caching
/static --> enable caching
/* --> web-alb

when you did changes to website, create invalidation --> CDN will delete data from edge locations

CICD
---------------------

developer doing changes
build everything again
compile
dependencies install
scan
unit tests
zip and push to S3/nexus

CD
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