Relational Database(RDS)

 RDS

Relational database has database which has rows and columns.

Rows:Is the data for fields

Columns: Has the titles of fields to represent the data.

Relational Database on AWS:

• SQL server
• Oracle
• MySql server
• PostgreSql
• Aurora
• MariaDB

RDS has two key features.

1. Multi-AZ: For disaster recovery

When we observe the below pic, EC2 instance is hosting a website with DNS name : myexapledb...

and website is communicating with Primary database.But there is some issue with Primary database which stops functioning, so website automatically pointing to the Read replica server , which is a back up of the Primary database.This is called Multi-AZ disaster recovery to provide the HA for the website.

1. Read replica: For performance: Which will give the HA to the website/app when disaster recovery happens.

Whenever data we are writing to the primary database , it automatically writing a backup to the other database which is read replica.

This is how it works when it starts reading from the read replica.

Non relational databases

In Non relational DB , There is no mandatory that every field will have the value but incase of RDS, every field(column) has the value.

For ex:

Id	Name	Emp id	age	company
1	Krishna	ab12	30
2	Arjun	cd34	23	TCS
3	sathya	ef22	35

OLTP:Online transaction processing, which provides the data for transaction basis

OLAP: Online Analytical Processing, which Provides the data analytical basis.

Elastic cache:

is a web service , that makes easy to deploy , operate and scale in-an memory cache in the cloud.

this service improves the performance of the webapps by allowing you to retrive information from fast, managed cache instead of relying on entirely slower disk based databases.

Caching will be done in two ways. i.e memcache and redis.

Redshift is a dataware housing technology and it is used for business intelligence purpose.

and this is OLAP purpose.

Simple task :

Creating website using wordpress and mysql server as backend using EC2.

Select RDS service under Data bases from the AWS services and create database.

select mysql and version

Template: Free tier

Name of the RDS instance: MySampleDB, this is not database name.

Backup retention period: 0 days and keep everything as default.

Finally click on "Create database".

After few mins Database will be created and it will be in "available" status.

Now lets go and create EC2 instance.

While creating EC2, instance PHP and mysql and tomcat by using the below script.

Bootstrap Script

#!/bin/bash

yum install httpd php php-mysql -y

cd /var/www/html

wget https://wordpress.org/wordpress-5.1.1.tar.gz

tar -xzf wordpress-5.1.1.tar.gz

cp -r wordpress/* /var/www/html/

rm -rf wordpress

rm -rf wordpress-5.1.1.tar.gz

chmod -R 755 wp-content

chown -R apache:apache wp-content

service httpd start

chkconfig httpd on

Once EC2 is up, you can copy your Public IP and paste it in the browser, you can see below page.

click on "lets go" Database host: RDS endpoint name

In my case its have to fill as below

once you click on submit it will show the below page

So, now you need to follow the above instruction.

i.e. We need to create the wp-config.php file and paste the following text into it.

connect to EC2 and and create a wp-config.php file and paste the content with Sudo access.

Now go back to the browser and  click on "run the installation"

fill the form as below

After that click on "install word press" it will show the below page.

Now your wordpress is installed and with mysql database as database.

Now we successfully installed PHP,wordpress and able to setup RDS database(mysql) as backend.

Thank you for reading 👍👍👍👍👍