Infrastructure as Code (IaC) has become a popular approach to manage and provision infrastructure. It enables teams to manage infrastructure as code and use version control systems to track changes. However, implementing IaC can be complex and involve multiple tools and platforms. This is where Jenkins Pipeline, Terraform, and Ansible come in to simplify and automate infrastructure management.

Jenkins Pipeline is an extensible platform for automating software delivery pipelines. It provides a flexible way to define continuous delivery pipelines as code, allowing you to define the entire software delivery process from code commit to deployment. Terraform is a popular open-source tool for building, changing, and versioning infrastructure. It enables teams to describe their infrastructure as code and automate the provisioning of resources. Ansible is an open-source automation tool for configuring and managing computers and network devices. It allows you to automate complex IT tasks, from application deployment to network automation.

Combining Jenkins Pipeline, Terraform, and Ansible allows you to manage infrastructure as code, automate the provisioning and configuration of resources, and streamline your continuous delivery pipeline.

1. To provision a virtual machine with an application installed, you can use Terraform to define the virtual machine resource and Ansible to install the application.
2. Terraform allows you to define the infrastructure as code and automate the provisioning of resources.
3. Ansible allows you to automate the configuration and management of computers and network devices, making it an ideal tool for installing and configuring software on virtual machines.
4. Jenkins Pipeline can automate the entire process, from provisioning the virtual machine to installing the application, making it faster, more reliable, and more efficient.
5. By using Terraform, Ansible, and Jenkins Pipeline together, you can automate the delivery of software, manage infrastructure as code, and achieve greater efficiency and consistency in your infrastructure management processes.

Let's take a look at an example of how to use these tools together. Suppose you want to provision a virtual machine with PostgreSQL installed. You can use Terraform to define the virtual machine resource and Ansible to install PostgreSQL. You can then use Jenkins Pipeline to automate the entire process, from provisioning the virtual machine to installing PostgreSQL.

The Terraform configuration file defines the virtual machine resource, and the Ansible playbook installs PostgreSQL. The Jenkins Pipeline script automates the entire process, using Terraform and Ansible to provision and configure the virtual machine.

pipeline {
    agent any

    stages {
        stage('Terraform Apply') {
            steps {
                sh 'terraform init'
                sh 'terraform apply -auto-approve'
            }
        }
        stage('Ansible Provisioning') {
            steps {
                ansiblePlaybook credentialsId: 'ansible-ssh', inventory: 'localhost,', playbook: 'postgres.yml'
            }
        }
    }

}

The Jenkins Pipeline script has two stages. The first stage applies the Terraform configuration to create the virtual machine, and the second stage runs the Ansible playbook to install PostgreSQL. The ansiblePlaybook command is used to run the playbook using the ansible-ssh credentials.

Teraform script:

# define provider
provider "virtualbox" {}

# define instance
resource "virtualbox_vm" "postgres" {
  name   = "postgres"
  memory = 2048
  vram   = 16

  # create private network for postgres to listen on
  network_interface {
    hostonly_adapter = "vboxnet0"
  }

}

Ansible script:

- hosts: all
  become: true
  tasks:
  - name: Install PostgreSQL
    apt:
      name: postgresql
      update_cache: yes
    notify:
    - start postgresql service

  - name: Start PostgreSQL service
    service:
      name: postgresql
      state: started

By using Jenkins Pipeline, Terraform, and Ansible together, you can automate the provisioning and configuration of infrastructure, making it faster, more reliable, and more efficient. You can define your entire infrastructure as code and use version control systems to track changes, making it easier to collaborate and manage complex infrastructure.