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https://github.com/csye7125-fall2023-group05/infra-jenkins

Jenkins server hosted on AWS EC2 with Infrastructure as Code setup using Hashicorp Terraform
https://github.com/csye7125-fall2023-group05/infra-jenkins

aws-ec2 ci-cd-pipeline elastic-ip github-actions hashicorp-terraform iac iac-module iac-terraform infrastructure-as-code jenkins jenkins-server terraform terraform-modules

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Jenkins server hosted on AWS EC2 with Infrastructure as Code setup using Hashicorp Terraform

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README 

        
# Infrastructure setup for Jenkins



[![Terraform IaC template validation for Jenkins](https://github.com/cyse7125-fall2023-group05/infra-jenkins/actions/workflows/tf-validate.yml/badge.svg?branch=master)](https://github.com/cyse7125-fall2023-group05/infra-jenkins/actions/workflows/tf-validate.yml)



Hashicorp Terraform is a Infrastructure as Code tool which is used to provision infrastructure and manage resources in any cloud or data center.



We will be using this tool to provision our Jenkins server.



## :arrow_heading_down: Installation



Install Terraform using Homebrew (only on MacOS):



> For any other distros, please follow the [setup guide in the official docs](https://developer.hashicorp.com/terraform/tutorials/aws-get-started/install-cli#install-terraform).



- First, install the HashiCorp tap, a repository of all our Homebrew packages.



```bash

brew tap hashicorp/tap

```



- Now, install Terraform with `hashicorp/tap/terraform`.



```bash

# This installs a signed binary and is automatically updated with every new official release.

brew install hashicorp/tap/terraform

```



- To update to the latest version of Terraform, first update Homebrew.



```bash

brew update

```



- Then, run the upgrade command to download and use the latest Terraform version.



```bash

brew upgrade hashicorp/tap/terraform

```



### :white_check_mark: Verify Installation



Verify that the installation worked by opening a new terminal session and listing Terraform's available subcommands.



```bash

terraform -help

```



- Add any subcommand to terraform -help to learn more about what it does and available options.



```bash

terraform -help plan

```



> NOTE: If you get an error that `terraform` could not be found, your `PATH` environment variable was not set up properly. Please go back and ensure that your `PATH` variable contains the directory where Terraform was installed.



### :+1: Enable tab completion



- If you use either Bash or Zsh, you can enable tab completion for Terraform commands. To enable autocomplete, first ensure that a config file exists for your chosen shell.



```bash

# bash

touch ~/.bashrc

# zsh

touch ~/.zshrc

```



- Install the autocomplete package



```bash

terraform -install-autocomplete

```



## :wrench: Working with Terraform



1. Initialize Terraform

   This installs the required providers and other plugins for our infrastructure.



   ```bash

   # run in the `root` dir

   terraform init

   ```



2. Create a `.tfvars` using the `example.tfvars` template.



3. Validate the terraform configuration



   ```bash

   terraform validate

   ```



4. Plan the cloud infrastructure

   This command shows how many resources will be created, deleted or modified when we run `terraform apply`.



   > NOTE: Remember to set your aws profile in the terminal to run the commands going forward



   ```bash

   export AWS_PROFILE=root

   terraform plan -var-file=".tfvars"

   ```



5. Apply the changes/updates to the infrastructure to create it



   ```bash

   # execute the tf plan

   # `--auto-approve` is to prevent tf from prompting you to say y/n to apply the plan

   terraform apply --auto-approve -var-file=".tfvars"

   ```



6. To destroy your infrastructure, use the command:



   ```bash

   terraform destroy --auto-approve -var-file=".tfvars"

   ```



## :file_cabinet: Terraform Backend



> NOTE: This is the recommended best practice.



This is a storage location within AWS from where we access out `.tfstate` file.



> All the information about the infrastructure resources are defined in the `.tfstate` file when we run `terraform apply`. So next time when we run `terraform apply`, it will only compare the *desired state* to the *actual state*.



If we do not use a `backend` to store our `.tfstate` file, it is stored locally on a server (if we provision our infrastructure through a server) or on our local development workstation. The `.tfstate` file may also contain confidential credentials. In order to avoid these problems, it is recommended to use the terraform `backend` to store the `.tfstate` file.



Now, when we run the `terraform apply` command, the `.tfstate` will be accessed through the AWS S3 bucket.



> NOTE: The terraform `backend` does not allow the use of tfvars, so we hardcode these values in the configuration.



```tf

terraform {

  backend "s3" {

    bucket         = "tfstate-sid"

    key            = "backend/infra-jenkins.tfstate"

    region         = "us-east-1"

    dynamodb_table = "infra-state"

  }

}

```



## 🔌 Elastic IP



We will manually configure the elastic IP that we will associate and disassociate the IP with our Jenkins instance. To associate this with our `doman.tld`, we will also create an entry in our hosted zone for `A record`, which will contain the elastic IP configured in the previous step.



This will enable our EC2 instance to be associated to the manually configured elastic IP everytime we setup our infrastructure using Terrform, and disassociate the elastic IP when we tear down our Infrastructure using Terraform.