DevOps Classroom notes 24/Dec/2023

Ntier in AWS

Security group

• The terraform template which we created

variable "security_group_info" {
  type = object({
    name        = string
    description = string
    vpc_id      = string
    rules = list(object({
      from_port   = string
      to_port     = string
      type        = string
      protocol    = string
      cidr_blocks = list(string)
    }))
  })

  default = {
    name        = "web"
    description = "this is web security group"
    vpc_id      = ""
    rules = [{
      from_port   = "22"
      to_port     = "22"
      type        = "ingress"
      protocol    = "tcp"
      cidr_blocks = ["0.0.0.0/0"]
      },
      {
        from_port   = "80"
        to_port     = "80"
        type        = "ingress"
        protocol    = "tcp"
        cidr_blocks = ["0.0.0.0/0"]
      },
      {
        from_port   = "443"
        to_port     = "443"
        type        = "ingress"
        protocol    = "tcp"
        cidr_blocks = ["0.0.0.0/0"]
      }
    ]
  }

}



resource "aws_security_group" "web" {
  description = var.security_group_info.description
  name        = var.security_group_info.name
  vpc_id      = var.security_group_info.vpc_id


}

resource "aws_security_group_rule" "allowssh" {
  count             = length(var.security_group_info.rules)
  from_port         = var.security_group_info.rules[count.index].from_port
  to_port           = var.security_group_info.rules[count.index].to_port
  type              = var.security_group_info.rules[count.index].type
  security_group_id = aws_security_group.web.id
  protocol          = var.security_group_info.rules[count.index].protocol
  cidr_blocks       = var.security_group_info.rules[count.index].cidr_blocks
}

output "security_group_id" {
  value = aws_security_group.web.id
}

output "security_group_name" {
    value = aws_security_group.web.name

}

Module

• Module is reusable terraform template.
• Modules can be created from existing templates
• Modules can be picked up from
  • local filesystem
  • url
  • git
  • terraform registry
• demo of module:
  • lets use a vpc module Refer Here
• Refer Here for usage of module
• Refer Here for official docs on terraform modules
• Refer Here for the changes done to create a local module and using the module to create web security group
• Now lets try creating the business security group and data security
  
• Exercise: Make azure’s network security group also a module

Taints and replace in terraform

• Taint: Deleting a particlular resource during next execution Refer Here
• Replace: It is recommended to use replace as taint is deprecated.

Terraform graph

• Refer Here
• Graph view created from the template written by us
  

Activities:

• Write a terraform template or use existing module
  • Create a linux vm in azure (standard_b1s)
  • Creating an ubuntu ec2 instance in aws. (t2.micro)