session-33.txt

R53 records
----------------
backend.daws78s.online --> private IP
frontend.daws78s.online --> private ip
daws78s.online --> public ip --> private ip

[frontend]
daws78s.online

[backend]
backend.daws78s.online

db.daws78s.online = RDS end point

frontend_public
frontend_ansible
frontend_bastion

frontend SG
-----------
22 expense-dev-ansible


CNAME vs A

A --> IP
CNAME --> another domain
expense-dev.czn6yzxlcsiv.us-east-1.rds.amazonaws.com

for i in $(ls -dr */) ; do echo ${i%/}; cd  ${i%/} ; terraform destroy -auto-approve ; cd .. ; done


Client, Delivery Manager, Team leads, Team members

DB lead
----------
team members

Backend lead
----------
team members

frontend lead
----------
team members

client --> ui work --> DM --> frontend lead --> team members
client --> backend work --> DM --> backend lead --> team members
client --> data work --> DM --> data lead --> team members

delivery manager balancing the load of work == Load Balancer
client = User
teams = target group
members = ec2 instances

https://www.facebook.com --> 443
http://www.facebook.com --> 80

health check
---------------
un healthy thershold --> 2 times try --> remove him
3 times --> He is available --> healthy

if frontend, port no 80 is working and able to get response --> healthy
http://<ip-address>:80

if backend

http://<ip-address>:8080 --> no response --> unhealthy --> no more requests further

HTTP codes
-----------------------
Informational responses (100 – 199) 
Successful responses (200 – 299)
Redirection messages (300 – 399)
Client error responses (400 – 499) --> client side mistake
400
404 --> not found
Server error responses (500 – 599)

facebook.com/fjdsfLFDHS --> 404
403 --> FORBIDDEN

something wrong happened , please try again later
there is server side issue, we are working on it

ALB
listener
rules
target groups
health checks