Terraform

Terraform

Requirements

AWS Account
Git
Basics in System administration and networking basics
terraform [command] -help syntax for a command

Infrastructure as code (IaC)

Introduction to Infrastructure as Code with Terraform
Advantages of Infrastructure as code
- Easily Repeatable
- Easily Readable
- Operational certainty with "terraform plan"
- Standardized environment builds
- Quickly provisioned development environment
- Disaster Recovery

What is Terraform?

Terraform is a tool for building, changing, and versioning infrastructure safely and efficiently. Terraform can manage existing and popular service providers as well as custom in-house solutions.
Infrastructure management tool made by HashiCorp or open-source infrastructure as code software tool
Provision, manage, and maintain cloud resources like servers, networking, storage.
Terraform is for managing the base infrastructure Not a configuration Management System
Terraform works with Docker, Kubernetes, Cloud.
Terraform presently supports more than 70 providers.

Terraform vs. Chef, Puppet, etc.

Configuration management tools install and manage software on a machine that already exists. Terraform is not a configuration management tool, and it allows existing tooling to focus on their strengths: bootstrapping and initializing resources.

Terraform focuses on the higher-level abstraction of the datacenter and associated services, while allowing you to use configuration management tools on individual systems. It also aims to bring the same benefits of codification of your system configuration to infrastructure management.

If you are using traditional configuration management within your compute instances, you can use Terraform to configure bootstrapping software like cloud-init to activate your configuration management software on first system boot.

Installing Terraform - Windows

Visit Terraform Download CLI > choose the operating system.
Choose folder to download in %USERPROFILE%\bin create bin folder if not available
Extract the file into %USERPROFILE%\bin
Search for Environment Variable on your machine > click Environment Variables... on User variables for "your-user" highlight Path click New type into the field %USERPROFILE%\bin click OK then OK then OK to exit Environment Variables.
Open a new PowerShell and type terraform to check if Terraform was inserted into your Path correctly.

Visit Install Terraform Documentation

Installing Terraform - Linux

wget https://releases.hashicorp.com/terraform/0.14.6/terraform_0.14.6_linux_amd64.zip 64-bit Terraform Download CLI
unzip terraform_0.14.6_linux_amd64.zip
sudo mv terraform /bin
rm terraform_0.14.6_linux_amd64.zip
terraform --version

Create AWS IAM user

Login to AWS Account
Click Users on Dashboard then Add user
Insert a username. Example terraform
Select AWS access type Programmatic access
Go next select Attach existing policies directly then check AdministratorAccess this is bad practice and should be avoided if you know what policies to assign your username to use terraform
Click Next and Review
Download the .CSV file containing the credentials

Creating credentials file

Open credential file from previous step and edit using vscode
Delete the first line containing headings
Delete username comma and password field
Delete the website at the end
Add [default] at the beginning of the file
Add before Access key ID aws_access_key_id=
Add before Secret access key aws_secret_access_key=
Save in %USERPROFILE%\.aws\credentials credentials file has no extension so make sure it don't have via the command line
mv new_user_credentials.csv credentials

Git init & terraform init

Open GitBash and type command mkdir ~/Desktop/terraform
cd ~/Desktop/terraform then init git by git init
Create file first_code.tf by command vim first_code.tf
To change the default location of the credentials file use shared_credentials_file = "credentials path" beneath region = "us-west-2" in first_code.tf file
Add terraform to .gitignore (Important security measurement)
- .gitignore can be downloaded or forked from this repo
- Contains windows/linux/mac/terraform
- Create your own via Toptal
git add * then git commit -m "init commit and config file"
terraform init
git push

Format and validate the configuration

The terraform fmt command automatically updates configurations in the current directory for easy readability and consistency.
Terraform will return the names of the files it formatted. In the case, your configuration file was already formatted correctly, Terraform won't return any file names.
the built in terraform validate command will check and report errors within modules, attribute names, and value types.

Logging for Terraform

Instructions for Windows & Linux

Terraform apply

Executing terraform apply will generate a plan and prompt to execute.
terraform apply filename.plan will apply without prompting yes/no assumes you have already revised the plan
terraform apply -auto-approve generate plan, apply plan without prompting yes/no use at your own risk

Terraform plan

Will execute automatically if terraform apply executed
Plan will show each step that will be executed
Will check the state between your configurations and real physical resources
Use [option] -out=filename.plan to generate plan and save it to a file, otherwise the plan generated might not be the same when getting to apply stage.
To inspect the plan terraform show filename.plan
cat filename.plan don't work since it's a binary file

Terraform state

cat terraform.tfstate this will show json information about the local state\ ** local state and remote state might be out of sync until terraform pull the state from the infrastructure **
The file may include sensitive information therefore, the need to make sure to include the .tfstate extension in .gitignore file is necessary in order to disable git pushing to a public github
Below is a screenshot from Terraform Documentation
Remote State is part of a feature on Terraform call Backends Read more about Backends here
terraform state has a two handy subcommands list that shows a list of resources and show [resource] shows a specific resource. terraform show will dump all resources state.

Terraform graph

Terraform builds a graph part of the plan and can be exported then rendered visually.
terraform graph the syntax of the output is DOT
Visualizing DOT require a graph visualizer. Ex: http://webgraphviz.com

Terraform Resources

Building blocks of Terraform
Define the "what" of your infrastructure
Different settings for every provider

Required Providers Providers

Terraform Variables

Terraform Provisioner

Provisioners

Perform Dynamic Operations with Functions

Find Create an SSH key and a security group resource
Perform Dynamic Operations with Functions Link

Query Data Sources

Tutorial Link

Protect Sensitive Input Variables

Tutorial Link

Manage Kubernetes Resources via Terraform

Tutorial Link

Reuse Configuration with Modules

Tutorials Link

Challenges & Workarounds

If terraform validate was successful and your apply still failed, you may be encountering a common error.

If you use a region other than us-east-1, you will also need to change your ami, since AMI IDs are region specific. Choose an AMI ID specific to your region by following these instructions, and modify *.tf with this ID. Then re-run terraform apply.
If you do not have a default VPC in your AWS account in the correct region, navigate to the AWS VPC Dashboard in the web UI, create a new VPC in your region, and associate a subnet and security group to that VPC. Then add the security group ID (vpc_security_group_ids) and subnet ID (subnet_id) into your aws_instance resource, and replace the values with the ones from your new security group and subnet. Save the changes to *.tf, and re-run terraform apply. full article here

wilbur61 / terraform Goto Github PK

terraform's Introduction