notes/session-49.txt at main · daws-88s/notes · GitHub

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Family History

100 years back

joint familities

5 couples
20 children
25-30 members
individual big houses

advantages
==========
no shared, we have freedom
privacy
everything in our control, we can design

disadvantages
==========
too much cost
maintainance on us
time taking process

1 couple
2 or 3 kids
a flat is enough

advantages
==========
low maintainance
less cost
just pay and joint
less time

disadvantages
==========
less privacy
space is shared
we dont have control
more rules

individuals
==========
single person
shared room/pg

advantages
==========
less time
no maintainance at all
no responsibility
too less cost

disadvantages
=========
no privacy
everything is shared
0 control


Legacy = Frontend + Backend
JSP+Servlets+HTML
150Mb

disadvantages
=============
a small problem in frontend/backend crash everything
a small change should create new version.. new application release
size is very big
physical baremetal servers

monolitic
============
frontend  -> API -> backend(catalogue+user+cart+ratings etc.)
angular js

advantages
==========
problem in frontend can't create problems in backend..both are different
release process is different
size is 50% reduced
speed of provisioning(boot time) is reduced

Virtulisation -> 100GB RAM, 2TB HD, 16 cores, host OS(vmware esxi)
				VM -> 1GB RAM, 8GB HD, 1 processor, Guest OS(windows)
				VM -> 2GB RAM, 20GB HD, 2 processor, Guest OS(Linux)

disadvantages
==========
all components must use same programming language
single component problem can crash entire backend


MicroServices
==========
frontend -> user, cart, catalogue, ratings, etc..

advantages
==========
multiple programming languages
release process is different
problem in a single component still keeps the application running
less downtime
connected through API
	URL, Method, Sample request, expected response, status code


containerisation
===============
1. no resource allocation, can use dynamically
2. less cost
3. less boot time
4. less size
5. portable and immutable
6. scalable and reliable
7. less privacy, but we can address this

Docker
======
AMI = OS + System packages + App run time + App code + App dependencies -> Instance/Server/VM -> AMI ID
Docker Image = Bare minimum OS + System packages + App run time + App code + App dependencies -> Container

OS + System packages


sudo dnf -y install dnf-plugins-core
sudo dnf config-manager --add-repo https://download.docker.com/linux/rhel/docker-ce.repo
sudo dnf install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin -y
sudo systemctl start docker
sudo systemctl enable docker
sudo usermod -aG docker ec2-user

logout and login again

docker commands
===============
docker ps -> running containers
docker images -> images available
docker pull nginx -> pull the image from dockerhub
docker create nginx -> creates the containers, status is created
docker start container-id -> start the container
docker rm container-id
docker rmi nginx
docker run nginx = pull + create + start

nginx = OS + system packages + nginx software