$ vim user_input.py
roll_num = int(input("Enter your roll no.:"))
message = "Hello user your roll number is " + str(roll_num)
print(message)
:x

or

$ vim user_input.py
roll_num = int(input("Enter your roll no.:"))
print("Hello user your roll number is " + str(roll_num))
:x 

$ python user_input.py

create directory postgres and navigate
$ mkdir postgres && cd postgres
create main.tf file
$ vim main.tf

provider "aws" {
}
resource "aws_security_group" "rds_sg" {
  name = "rds_sg"
  ingress {
    from_port       = 5432
    to_port         = 5432
    protocol        = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

resource "aws_db_instance" "myinstance" {
  engine               = "postgres"
  identifier           = "myrdsinstance"
  allocated_storage    =  20
  engine_version       = "14"
  instance_class       = "db.t3.micro"
  username             = "myrdsuser"
  password             = "myrdspassword"
  parameter_group_name = "default.postgres14"
  vpc_security_group_ids = ["${aws_security_group.rds_sg.id}"]
  skip_final_snapshot  = true
  publicly_accessible =  true
}

output "rds_endpoint" {
  value = "${aws_db_instance.myinstance.endpoint}"
}

save and exit
$ terraform init
$ terraform plan
$ terraform apply -auto-approve
Install postgres client in local machine
$ sudo apt install -y postgresql-client
To access AWS postgresql RDS instance
$ psql -h <end_point_URL> –p=5432 –username=myrdsuser –password –dbname=mydb
To destroy postgresql RDS instance
$ terraform destroy -auto-approve

create directory mysql and navigate
$ mkdir mysql && cd mysql
create main.tf
$ vim main.tf

provider "aws" {
}
resource "aws_security_group" "rds_sg" {
  name = "rds_sg"
  ingress {
    from_port       = 3306
    to_port         = 3306
    protocol        = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

resource "aws_db_instance" "myinstance" {
  engine               = "mysql"
  identifier           = "myrdsinstance"
  allocated_storage    =  20
  engine_version       = "5.7"
  instance_class       = "db.t2.micro"
  username             = "myrdsuser"
  password             = "myrdspassword"
  parameter_group_name = "default.mysql5.7"
  vpc_security_group_ids = ["${aws_security_group.rds_sg.id}"]
  skip_final_snapshot  = true
  publicly_accessible =  true
}

output "rds_endpoint" {
  value = "${aws_db_instance.myinstance.endpoint}"
}

save and exit
$ terraform init
$ terraform plan
$ terraform apply -auto-approve
install mysql client in local host
$ sudo apt install mysql-client
To access the mysql
$ mysql -h <end_point_URL> -P 3306 -u <username> -p
To destroy the mysql RDS instance
$ terraform destroy -auto-approve

module "s3_bucket" {
  source = "terraform-aws-modules/s3-bucket/aws"

  bucket = "kaniyam-bucket"
  acl    = "private"

  control_object_ownership = true
  object_ownership         = "ObjectWriter"

  versioning = {
    enabled = true
  }
}

provider "aws" {
  region = "ap-south-1"
}

resource "aws_s3_bucket" "example" {
  bucket = "example-my"
}

resource "aws_s3_bucket_ownership_controls" "ownership" {
  bucket = aws_s3_bucket.example.id
  rule {
    object_ownership = "BucketOwnerPreferred"
  }
}

resource "aws_s3_bucket_public_access_block" "pb" {
  bucket = aws_s3_bucket.example.id

  block_public_acls       = false
  block_public_policy     = false
  ignore_public_acls      = false
  restrict_public_buckets = false
}

resource "aws_s3_bucket_acl" "acl" {
  depends_on = [aws_s3_bucket_ownership_controls.ownership]
  bucket = aws_s3_bucket.example.id
  acl    = "private"
}

create directory s3-demo and navigate
$ mkdir s3-demo && cd s3-demo
create a demo file sample.txt and contents
$ echo “this is sample object to store in demo-bucket” > sample.txt
create main.tf file
$ vim main.tf

provider "aws" {
  region = "ap-south-1"
}

resource "aws_s3_bucket" "example" {
  bucket = "mydemo-bucket1"
}

resource "aws_s3_object" "object" {
  bucket = aws_s3_bucket.example.bucket
  key    = "sample.txt"
  source = "./sample.txt"
}

save and exit
$ terraform init
$ terraform plan
$ terraform apply -auto-approve

create directory s3 and navigate to the directory
$ mkdir s3 && cd s3
create main.tf file
$ vim main.tf

provider "aws" {
  region = "ap-south-1"
}

resource "aws_s3_bucket" "my_bucket" {
  bucket = "mydemo-bucket"
}

save and exit
$ terraform init
$ terraform plan
$ terraform apply -auto-approve
To destroy the bucket
$ terraform destroy -auto-approve

Install AWS CLI
$ sudo apt install awscli -y
To check for the version
$ aws –version
To configure AWS account crdentials
copy the access and secret key from AWS account security credentials
$ aws configure
AWS Access Key ID [None]: ***************** 
AWS Secret Access Key [None]: ******************
Default region name [None]: ap-south-1
Default output format [None]: json or table or text

create directory ec2 and navigate to the directory
$ mkdir ec2 && cd ec2
create main.tf file
$ vim main.tf

provider "aws" {
  region = "ap-south-1"
}

resource "aws_instance" "app_server" {
  ami = "ami-03f4878755434977f"
  instance_type = "t2.nano"
  subnet_id = "subnet-0ccba3b8cfd0645e2"
  key_name = "awskey"
  associate_public_ip_address = "true"
  tags = {
    Name = "demo-server"
  }
}

output "public_ip" {
  description = "public ip of the instance"
  value = aws_instance.app_server.public_ip
}

save and exit
initialize the terraform
$ terraform init
$ terraform plan
$ terraform apply -auto-approve
it will create the AWS EC2 instance with output the public ip of the instance

To destroy the instance
$ terraform destroy -auto-approve

Method1: Package manager
$ wget -O- https://apt.releases.hashicorp.com/gpg | sudo gpg –dearmor -o /usr/share/keyrings/hashicorp-archive-keyring.gpg
$ echo “deb [signed-by=/usr/share/keyrings/hashicorp-archive-keyring.gpg] https://apt.releases.hashicorp.com $(lsb_release -cs) main” | sudo tee /etc/apt/sources.list.d/hashicorp.list
$ sudo apt update && sudo apt install terraform
$ terraform version
To get help options
$ terraform -h

Method2: Binary download
download the binary from wget https://developer.hashicorp.com/terraform/downloads
$ wget https://releases.hashicorp.com/terraform/1.6.6/terraform_1.6.6_linux_amd64.zip

extract using unzip
$ unzip terraform_1.6.6_linux_amd64.zip
$ mv terraform /usr/local/bin/
$ terraform version
$ terraform -h

To remove terraform binary method
$ sudo rm -f /usr/local/bin/terraform

To remove terraform package manager method
$ sudo apt remove terraform --purge

step1: create EC2 instance

step2:
Create an IAM Role and attach it to EC2 instance 
IAM 
EC2 
VPC 
CloudFormation 
Administrative access

In the EC2 instance install kubectl and eksctl
step3: install kubectl
$ curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
$ chmod +x ./kubectl
$ sudo mv ./kubectl /usr/local/bin
$ kubectl version --client

step4: install eksctl
$ curl --silent --location "https://github.com/weaveworks/eksctl/releases/latest/download/eksctl_$(uname -s)_amd64.tar.gz" | tar xz -C /tmp
$ sudo mv /tmp/eksctl /usr/local/bin
$ eksctl version

step5: install aws-iam-authenticator
$ curl -Lo aws-iam-authenticator https://github.com/kubernetes-sigs/aws-iam-authenticator/releases/download/v0.6.14/aws-iam-authenticator_0.6.14_linux_amd64
$ chmod +x ./aws-iam-authenticator
$ mkdir -p $HOME/bin && cp ./aws-iam-authenticator $HOME/bin/aws-iam-authenticator && export PATH=$HOME/bin:$PATH
$ echo 'export PATH=$HOME/bin:$PATH' >> ~/.bashrc
step6:
create clusters and nodes
$ eksctl create cluster --name dhana-cluster --region ap-south-1 --node-type t2.small

step7:
Validate your cluster using by creating by checking nodes and by creating a pod
$ kubectl get nodes
$ kubectl run pod tomcat --image=tomcat 
$ kubectl run pod nginx --image=nginx

To delete the cluster dhana-cluster
$ eksctl delete cluster dhana-cluster --region ap-south-1

To create postgres DB
$ aws rds create-db-instance --db-instance-identifier demo-postgresql --db-instance-class db.t3.micro --engine postgres --master-username postgres --master-user-password passcode123 --allocated-storage 20

To describe and get the endpoint url
$ aws rds describe-db-instances --db-instance-identifier demo-postgresql | grep Address

To access the remote postgresql
$ psql --host=<endpoint_url> --port=5432 --username=postgres
--dbname=postgres --password

To delete the db instance without final snapshot and automated backups
$ aws rds delete-db-instance --db-instance-identifier demo-postgresql
--skip-final-snapshot --delete-automated-backups

To create a mysql db
$ aws rds create-db-instance --db-instance-identifier demo-mysql --db-instance-class db.t3.micro --engine mysql --master-username admin --master-user-password passcode123 --allocated-storage 20

To describe and get the endpoint url
$ aws rds describe-db-instances --db-instance-identifier demo-mysql | grep Address

To access the remote mysql DB
$ mysql -h <endpoint_url> -P 3306 -u admin -p

To delete the db instance without final snapshot and automated backups
$ aws rds delete-db-instance --db-instance-identifier demo-mysql --skip-final-snapshot --delete-automated-backups

choose the EBS volume and click modify
give the desired size to extend the volume
in Linux terminal umount the volume
$ sudo umount /data  (where the ebs volume is mounted)
$ sudo e2fsck -f /dev/xvdf
$ sudo resize2fs /dev/xvdf
mount the volume again
$ sudo mount -a
$ df -Th

To start a new session
# tmux new -s zha

To login to a tmux session
# tmux a -t zha
or
# tmux attach-session -t zha

# tmux kill-session -t zha
or
# tmux kill-session -t 1

# tmux detach
# tmux attach

update the server
# apt update

install necessary packages
# apt-get install apache2 mariadb-server php libapache2-mod-php php-mail php-mail-mime php-mysql php-gd php-common php-pear php-db php-mbstring php-xml php-curl unzip wget -y

check the php version
# php -v

view versions of FreeRADIUS available
# apt policy freeradius

install freeradius
# apt -y install freeradius freeradius-mysql freeradius-utils

stop the freeradius service
# systemctl stop freeradius.service

To run FreeRADIUS debug mode
# freeradius -X

login to mariadb and create DB , DB user and password
# mysql -u root
> CREATE DATABASE radius;
> GRANT ALL ON radius.* TO radius@localhost IDENTIFIED BY "PASSWORD";
> FLUSH PRIVILEGES;
> QUIT;

check the DB created
# mysql -u root -p -e "show databases;"

download the daloradius webGUI package from github
# wget https://github.com/lirantal/daloradius/archive/refs/tags/1.3.zip

extract the package
# unzip 1.3.zip

rename the folder
mv daloradius-1.3/ daloradius

To populate the database with the daloRADIUS schema. The .sql file is located in the ‘/contrib/db/’ folder.
we might have to change this path if you didn’t install it in the root destination.
# mysql -u root -p radius < contrib/db/fr2-mysql-daloradius-and-freeradius.sql
# mysql -u root -p radius < contrib/db/mysql-daloradius.sql

move the daloradius folder to /var/www/html
# mv daloradius /var/www/html/

rename the daloradius.conf.php.sample to daloradius.conf.php
# mv /var/www/html/daloradius/library/daloradius.conf.php.sample /var/www/html/daloradius/library/daloradius.conf.php

assign ownership of the daloRADIUS web configuration files to Apache
# chown -R www-data:www-data /var/www/html/daloradius/

configure the permissions of main configuration file to 664
# chmod 664 /var/www/html/daloradius/library/daloradius.conf.php

To allow the DaloRADIUS web interface to access FreeRADIUS,
to provide its database details in the configuration file for DaloRADIUS
add the database details(username, password and db name)
in the below file
# vim /var/www/html/daloradius/library/daloradius.conf.php

$configValues['CONFIG_DB_USER'] = 'radius';
$configValues['CONFIG_DB_PASS'] = 'PASSWORD';
$configValues['CONFIG_DB_NAME'] = 'radius';

:wq! save and exit

restart the freeradius and apache2 and check the status
# systemctl restart freeradius
# systemctl restart apache2
# systemctl status freeradius
# systemctl status apache2

access the daloradius
http://ip-address/daloradius/login.php

default username : administrator
default password : radius
To change the default password
config > operators > list operators > administrator > operator password and apply

For example to encrypt the password for
mysql_secure_installation using shell script

install these packages
$ sudo apt install sshpass gnupg2
create a file
$ touch .secrets
$ cat > .secrets
passcode123
^D
Encrypting Your Password
$ gpg -c .secrets
it will create a file with .secrets.gpg
to decrypt
$ gpg -dq .secrets.gpg

create the mariadb secure installation script
$ cat mariadb.sh
#!/bin/bash
apt install mariadb-server mariadb-client -y
systemctl enable mariadb.service
mysql_secure_installation <<EOF
y
n
y
gpg -dq secrets.gpg | sshpass
gpg -dq secrets.gpg | sshpass
y
y
y
y
EOF
:wq! save and exit

$ sudo chmod +x mariadb.sh
$ sh mariadb.sh

log in to remote mysql sever
change bind address to 0.0.0.0
# vim /etc/mysql/mysql.conf.d/mysqld.cnf
from
bind-address = 127.0.0.1
to
bind-address = 0.0.0.0
:wq! save and exit

Log in to mysql sever
$ sudo mysql -u root -p
mysql> CREATE DATABASE mydb;
mysql> CREATE USER 'grafana'@'%' IDENTIFIED BY 'zha123';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'grafana'@'%';
mysql> flush privileges;
mysql> exit

In grafana server
go to data sources
select MySQL  as data source
Name source name
Host : remote_mysql_server_ip:3306
database: dbname
username :  and password:
and give
save and test

$ mysql -u root -p
> CREATE USER 'grafana'@'localhost' IDENTIFIED BY '<your-password>';
> GRANT ALL PRIVILEGES ON *.* TO 'grafana'@'localhost';
> flush privileges;

$ wget https://www.mysqltutorial.org/wp-content/uploads/2018/03/mysqlsampledatabase.zip
$ unzip mysqlsampledatabase.zip
$ mysql -u username -p
mysql> source /root/mysqlsampledatabase.sql
mysql> show databases;
mysql > use classicmodels;
mysql > show tables;
mysql > select * from table_name;
mysql > exit;

$ sudo systemctl stop mysql.service
$ sudo systemctl status mysql.service
$ sudo systemctl set-environment MYSQLD_OPTS="--skip-networking --skip-grant-tables"
$ sudo systemctl start mysql.service
$ sudo systemctl status mysql.service
$ sudo mysql -u root
> flush privileges;
> USE mysql
> ALTER USER 'root'@'localhost' IDENTIFIED BY 'zha123';
> quit;
$ sudo systemctl unset-environment MYSQLD_OPTS
$ sudo systemctl revert mysql
$ sudo killall -u mysql
$ sudo systemctl restart mysql.service
$ sudo mysql -u root -p

$ apt update -y
$ apt install docker.io -y
$ docker --version
$ systemctl start docker
$ systemctl enable docker
$ systemctl status docker
$ curl -L "https://github.com/docker/compose/releases/download/v2.17.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
$ ls -lsh /usr/local/bin/docker-compose
$ chmod +x /usr/local/bin/docker-compose
$ ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose
$ docker-compose --version
$ mkdir -p ~/.docker/cli-plugins
$ curl -sSL https://github.com/docker/compose/releases/download/v2.0.1/docker-compose-linux-x86_64 -o ~/.docker/cli-plugins/docker-compose
$ chmod +x ~/.docker/cli-plugins/docker-compose
$ docker compose version

$ git clone https://github.com/frappe/frappe_docker
$ cd frappe_docker/
$ mkdir ~/gitops
$ echo 'TRAEFIK_DOMAIN=traefik.hashlabs.in' > ~/gitops/traefik.env
$ echo 'EMAIL=tkdana@gmail.com' >> ~/gitops/traefik.env
$ echo 'HASHED_PASSWORD='$(openssl passwd -apr1 Passw0rd | sed 's/\$/\\\$/g') >> ~/gitops/traefik.env
$ vim /etc/hosts
172.105.123.45 traefik.hashlabs.in
172.105.123.45 one.hashlabs.in
172.105.123.45 two.hashlabs.in
:wq!
$ docker-compose --project-name traefik --env-file ~/gitops/traefik.env -f overrides/compose.traefik.yaml -f overrides/compose.traefik-ssl.yaml up -d
$ echo "DB_PASSWORD=StrongPassw0rd" > ~/gitops/mariadb.env
$ docker-compose --project-name mariadb --env-file ~/gitops/mariadb.env -f overrides/compose.mariadb-shared.yaml up -d
$ cp example.env ~/gitops/erpnext-one.env
$ sed -i 's/DB_PASSWORD=123/DB_PASSWORD=StrongPassw0rd/g' ~/gitops/erpnext-one.env
$ sed -i 's/DB_HOST=/DB_HOST=mariadb-database/g' ~/gitops/erpnext-one.env
$ sed -i 's/DB_PORT=/DB_PORT=3306/g' ~/gitops/erpnext-one.env
$ sed -i 's/SITES=`erp.example.com`/SITES=\`one.hashlabs.in\`,\`two.hashlabs.in\`/g' ~/gitops/erpnext-one.env
$ echo 'ROUTER=erpnext-one' >> ~/gitops/erpnext-one.env
$ echo "BENCH_NETWORK=erpnext-one" >> ~/gitops/erpnext-one.env
$ docker-compose --project-name erpnext-one --env-file ~/gitops/erpnext-one.env -f compose.yaml -f overrides/compose.redis.yaml -f overrides/compose.multi-bench.yaml -f overrides/compose.multi-bench-ssl.yaml config > ~/gitops/erpnext-one.yaml
$ docker-compose --project-name erpnext-one -f ~/gitops/erpnext-one.yaml up -d
$ docker-compose --project-name erpnext-one exec backend bench new-site one.hashlabs.in --no-mariadb-socket --mariadb-root-password StrongPassw0rd --install-app erpnext --admin-password zha123
$ docker-compose --project-name erpnext-one exec backend bench new-site two.hashlabs.in --no-mariadb-socket --mariadb-root-password StrongPassw0rd --install-app erpnext --admin-password zha123

$ docker search httpd
$ docker pull centos/httpd 
$ docker images
$ docker run -d --name httpd_demo2 -p 8082:80 centos/httpd 
http://ip:8082

$ mkdir httpd && cd httpd

$ vim Dockerfile
FROM centos:7
MAINTAINER tkdhanasekar <tkdhanasekar@gmail.com>
RUN yum update -y
RUN yum install httpd -y
COPY index.html /var/www/html/
ENTRYPOINT ["/usr/sbin/httpd","-D","FOREGROUND"]
:wq!

$ vim index.html
<h1> This is CentOS httpd Docker Container </h1>
:wq!

$ docker build -t myhttpd .
$ docker run -d --name httpd_demo -p 8081:80 myhttpd
http://server_ip:8081