What is Terraform: Terraform provides a flexible abstraction of resources and providers. This model allows for representing everything from physical hardware, virtual machines, and containers, to email and DNS 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.
Using provisioners, Terraform enables any configuration management tool to be used to setup a resource once it has been created. Terraform focuses on the higher-level abstraction of the datacenter and associated services, without sacrificing the ability to use configuration management tools to do what they do best. It also embraces the same codification that is responsible for the success of those tools, making entire infrastructure deployments easy and reliable.
Setting up Terraform on Centos:
Terraform is available as single binary package for Linux distributions, which can be downloaded from https://www.terraform.io/downloads.html
Unzip the binary package and place it in the PATH of the machine. i.e: /bin/terraform
[root@node1 ~]# terraform --version
Terraform v0.11.3
[root@node1 ~]# which terraform
/usr/bin/terraform
[root@node1 ~]#
Terraform allows us to define and create complete infrastructure deployments in Azure. We build Terraform templates in a human-readable format that create and configure Azure resources in a consistent, reproducible manner..
First of all, we need to install Azure-cli on the terraform node. So terraform can interact with the azure. And we can do this using following steps.
[root@node1 ~]# rpm --import https://packages.microsoft.com/keys/microsoft.asc[root@node1 ~]# cat /etc/yum.repos.d/azure-cli.repo[azure-cli]name=Azure CLIbaseurl=https://packages.microsoft.com/yumrepos/azure-clienabled=1gpgcheck=1gpgkey=https://packages.microsoft.com/keys/microsoft.asc[root@node1 ~]# yum install azure-cli
We can login into the Azure environment using the bash shell environment variables or we can define details of our environment in terraform templates. First of all, we need to retrieve the details of our environment from Azure.
[root@node1 ~]# az login --username XXXXXXXXXX@hotmail.com --password XXXXXXXXXX
Then we need to create a service-principal to get interacted with Microsoft Azure service.
[root@node1 ~]# az ad sp create-for-rbac --role="Contributor" --scopes="/subscriptions/your_subscription_id_from_previoud_command"This command will give you the output in the follow format.{"appId": "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX","displayName": "azure-cli-2017","name": "http://azure-cli-2017-12-12-06-46-08","password": "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX","tenant": "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"}
Capture the AppID, password, and tenant id from the above output.
Now we can define a terraform environment. The good thing about Terraform is that we can write the template anywhere and then we can initialize and apply it.
First of all I am writing my template here to create the virtual machine in Azure environment. We need to define all the components or details of terraform within template.
You can download the template from here.
Or you can write it as below.
[root@node1 ~]# mkdir Terraform_Templates
[root@node1 ~]# vim Terraform_Templates/azure.tf
provider "azurerm" {
subscription_id="Your_subscrption_from_az_login_cli"
client_id="your_application_id_from_the_same_cli"
client_secret="Your_password_"
tenant_id="Tenant_id_from_the_same_cli"
}
resource "azurerm_resource_group" "rg" {
name = "testResourceGroup"
location = "westus2"
tags {
environment = "Terraform Demo"
}
}
# Creating a virtual network now.
resource "azurerm_virtual_network" "myTestNetwork" {
name = "myVnet"
address_space = ["10.0.0.0/16"]
location = "West US 2"
resource_group_name = "${azurerm_resource_group.rg.name}"
tags {
environment = "Terraform Demo"
}
}
# Create a subnet.
resource "azurerm_subnet" "myTestSubnet" {
name = "mySubnet"
resource_group_name = "${azurerm_resource_group.rg.name}"
virtual_network_name = "${azurerm_virtual_network.myTestNetwork.name}"
address_prefix = "10.0.1.0/24"
}
# Creating the public IPs.
resource "azurerm_public_ip" "myPublicIP" {
name = "myPublicIP"
location = "West US 2"
resource_group_name = "${azurerm_resource_group.rg.name}"
public_ip_address_allocation = "dynamic"
tags {
environment = "Terraform Demo"
}
}
# Creating the network Security Group and rules.
resource "azurerm_network_security_group" "mySecurityGroup" {
name = "myNetworkSecurityGroup"
location = "West US 2"
resource_group_name = "${azurerm_resource_group.rg.name}"
security_rule {
name = "SSH"
priority = 1001
direction = "Inbound"
access = "Allow"
protocol = "Tcp"
source_port_range = "*"
destination_port_range = "22"
source_address_prefix = "*"
destination_address_prefix = "*"
}
tags {
environment = "Terraform Demo"
}
}
#Creating network interface
resource "azurerm_network_interface" "myNic" {
name = "myNIC"
location = "West US 2"
resource_group_name = "${azurerm_resource_group.rg.name}"
network_security_group_id = "${azurerm_network_security_group.mySecurityGroup.id}"
ip_configuration {
name = "myNicConfiguration"
subnet_id = "${azurerm_subnet.myTestSubnet.id}"
private_ip_address_allocation = "dynamic"
public_ip_address_id = "${azurerm_public_ip.myPublicIP.id}"
}
tags {
environment = "Terraform Demo"
}
}
# Generate random text for an unique storage account name.
resource "random_id" "randomID" {
keepers = {
resource_group = "${azurerm_resource_group.rg.name}"
}
byte_length = 8
}
# Create storage account for boot diagnostics
resource "azurerm_storage_account" "mystorageaccount" {
name = "diag${random_id.randomID.hex}"
resource_group_name = "${azurerm_resource_group.rg.name}"
location = "West US 2"
account_tier = "Standard"
account_replication_type = "LRS"
tags {
environment = "Terraform Demo"
}
}
# create a virtual machine
resource "azurerm_virtual_machine" "myterraformvm" {
name = "myVM"
location = "West US 2"
resource_group_name = "${azurerm_resource_group.rg.name}"
network_interface_ids = ["${azurerm_network_interface.myNic.id}"]
vm_size = "Standard_F2s_v2"
storage_os_disk {
name = "myOsDisk"
caching = "ReadWrite"
create_option = "FromImage"
managed_disk_type = "Standard_LRS"
}
storage_image_reference {
publisher = "Canonical"
offer = "UbuntuServer"
sku = "16.04.0-LTS"
version = "latest"
}
os_profile {
computer_name = "myvm"
admin_username = "azureuser"
}
os_profile_linux_config {
disable_password_authentication = true
ssh_keys {
path = "/home/azureuser/.ssh/authorized_keys"
key_data = "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDAjdjirf79Se2O0BmiSSshhPyd
d0tKC8AVIjbUMDsLV3BaALrK7nzRHbctsVnftjmFkXP4X8bQvm6M/XoSGtu/dDqf
5qRreg0+dOJdHCLP1Yhg+M4VWpjLadxXgfXIZPum6pGrAPdm8ZWyQpVSHJrhx
Mlo+69Wol5lVx91oQ0yKptvQSy1HA0Y3ubUNcwfVEzSaQlLGK5CdS6vgVoe62R8
Z7UTn5SzDCvIBKxPPqvQzVD6IrtHmqP2LErL0TtCK4YOBrUygIk+9Bv2Y0xaHS2
Mz0wR4C+Tf+C2zxx8X6cIHl5JC7n7iqPgPiXvRHd/MSSxCIcvUWxhJZMy8okvgkj
H root@jenkins.example.com"
}
}
boot_diagnostics {
enabled = "true"
storage_uri = "${azurerm_storage_account.mystorageaccount.primary_blob_endpoint}"
}
tags {
environment = "Terraform Demo"
}
}
Save and exit the file. Now we can initialize the terraform in the same directory using the following command.
[root@node1 Terraform_templates]# terraform init
Before executing the template if you want to check that what and how many resources are going to be created. You can use below command.
[root@node1 Terraform_templates]# terraform plan
Finally, we can apply that plan and wait for 10 minutes around machine will be provisioned based on the details which we have given there.
[root@node1 Terraform_templates]# terraform apply
After machine get launched successfully we can get the public IP of the machine and we can access the same.
[root@node1 ~]# az vm show --resource-group myTestGroup --name myVM -d --query [publicIps] --o tsv
Now you can use listed IP to access the remote machine.
[root@node1 ~]# ssh Public_IP -l azureuser
In next post, we will see how we can use variables in the Terraform Template.
Till then Test it, Review it and give your input.
