Day2 - Terraform - class notes

 2/22/2022

Terraform - class notes

Recap

Teffaform Lifecycle

- init

- plan

- apply

- destroy

file: main.tf

we can add info about,

- provider 

- variables

- resources

It maintains the desired state.

How?

- it maintains the terraform.tfstate file. 

- By default it stores on local machine.

- You have to store it on remote location (such as s3 bucket, blob storage)

Terraform  authentication

- aws configure

1. Create 2 aws instance t2.mocro

ansible-host

ansible-client

2. Login to your system

$ sudo -i

# cd example

# cat backend.tf

# cat main.tf 

we want to seperate our instance on environment lavel,

dev, different type,

# vi variables.tf

   variable "image_id" {  

   type = string

}

google

variables in terraform 

# vi main.tf

terraform {

.

required_version = >= 0.14.9"

}

provider "aws" {

  profile = "default"

  region = "us-west-2"

}

.

resources "ami_instance" "app_server" {

  ami   = var.image_id

  instance_type = "t2.micro"

  tags = {

      name = "demo"

}

# vi dev.tfvars

image_id = "ami-830c94e3"

# cp dev.tfvars test.tfvars

# cp dev.tfvars prod.tfvars

here,

dev.tfvars => variable.tf => main.tf

# vi variables.tf

variable "image_id" {

type = string

default = ""  # defaine the default value here

}

# vi main.tf

# cp main.tf provider.tf

# vi provider.tf

terraform

provider

remove everything else

# tf plan -out dev.plan -var-file dev.tfvars

# vi main.tf

resources "ami_instance" "app_server" {

  ami   = var.image_id

  instance_type = "t2.micro"

  tags = {

      name = var.tag_name

}

# variables.tf

variable "imae_id"

type = string

default = ""

}

variable "tag_name"

type = string

default = "" ....  [8:00]

}

vi dev.tfvars

image_id = ani_84...

tag_name = "example Demo"

# terraform plan -out dev.plan -var-file dev.tfvars

If aws cli is not configured,

Go to aws, user -> credential -> delete old key and create new 

copy 

# aws configure

access key: *******

secret key: *******

# tf apply dev.plan 

It will create example demo instance. Login to aws console and check...

check out this url for example ..

https://github.com/qfitsolutions/aws-terraform-course/blob/master/EC2withJenkins/ec2_jenkins.tf

google: for other platform,

azure terraform examle

use: azure cli

login/authentication

- create terraform file

provider "azurerm"

for google cloud: google cloud,,,

you can configure more than one instance in the same config file..

for eg,

if you want to create an instance on different region,

get the ami for specific location, 

# vi variable.tf

# ec2_jenkins.tf

# terraform init

error: invalid quoted type constraints..

varibable "region"

  type = string # remove double quote

  default = "us_east_1"

read the error carefuly. change, try and learn ..

# tf init

warnings sometimes can be ignored ..

# sh abv.sh

# vi abc.sh

#!/bin/bash

yum update -y

yum install htpd.x86_68 -y

service httpd start/enable

echo "<h1> Deployed via terraform</h1>  sudo tee /var/www/html/index.html

yum install java.. -y

wget -o /etc/yum.repos.d/jenkins.repo

https://pkg.jenkins.io/redhat-stable/jenkins.repo

rpm --import htps://pkg.jenkins.io/redhat-stable/jenkins.io.key

yum upgrade

yum install fontconfig java-11-openjdk

yum install jenkins

# terraform destroy

==================

Ansible Roles

- Reusable components

on playbook:

decleare

jenkins playbook:

  roles:

    nginx

    jenkins

    java

nexus:

  roles:

    java

    nexus

    nginx

on terraform

we use resources

reources # ec2 ...vpc, security group, s3, eks ...

reusable components

parameters ...

next lavel extracction is module ..

modules contains multiple tf file

main.tf

module:

  vpc

  eks

  ecs

terraform template (abc.tf) => module => ec2_instance.tf

eks.tf

cf.tf

-------

# vi main.tf

download the code ..

https://github.com/easyawslearn/terraform-aws-instance-template

$ cat variables.tf

variable "ami_id" {}

variable "region" {}

variable "instance_type" {}

variable "tag" {

default="Testing"

}

$ cat main.tf

provider "aws" {

  region = "${var.region}"

}

resource "aws_instance" "web" {

  ami           = "${var.ami_id}"

  instance_type = "${var.instance_type}"

  tags = {

    Name = "${var.tag}"

  }

}

$ cat output.tf

output "instance_ip" {

  value = ["${aws_instance.web.public_ip}"]

}

# terrafrom init ..

# terraform plan

you can get ready made modules

vpc terraform module

vpc terraform 

----------------

Note: if you have dev.tfvars, test.tfvars, prod.tfvars

whatever you created last, will have latest tfvars file. which you can use to destroy the resources associated with. 

This is the reason, you will use teraform workspace..

# terrafrom workspace list

# terrfrom init --reconfigure

# terrafrom worksapce list

# terrafrom init -migrate-state 

# ls -ltr

# # rm -rf *.terraform

# terraform init

# terrafrom worksapce list

# terraform worksapce new dev

# terrafrom worksapce new test

# tf worksapce list

# tf worksapce select dev

# tf worksapce select prod

you can use different providers such as azure, gcp, k8s, docker

Continouse monitoring (CM)

- troubleshooting

- high availibity

- infracture /application health check

Monitorying are 2 types

- application

    - logs

    - status

- infre:

    CPU, memory, users, ports enable..

Log collection

----------------

n1/d1 (agent) n2/d2 n3/d3 =>  stored data (DB) dashboard (log analyzer) 

elk/splunk

preometheus/grafana

https://prometheus.io/docs/introduction/overview/

grafana is a dashboard and preometheus is a log collector

Tomorrow

--------

ELK stack