{"id":513614,"date":"2020-02-11T09:01:02","date_gmt":"2020-02-11T08:01:02","guid":{"rendered":"https:\/\/www.devoteam.com\/expert-view\/ansible-and-terraform-episode-3\/"},"modified":"2020-02-11T09:01:02","modified_gmt":"2020-02-11T08:01:02","slug":"ansible-and-terraform-episode-3","status":"publish","type":"expert-view","link":"https:\/\/devoteam.info\/be\/expert-view\/ansible-and-terraform-episode-3\/","title":{"rendered":"Ansible and Terraform: Episode 3"},"content":{"rendered":"

The magic explained<\/h2>\n

In the previous episode<\/a>, we<\/span> cloned<\/span> the code from <\/span>Github<\/span>,<\/span> <\/span>modified some variables and <\/span>provisioned<\/span> and<\/span> deployed two servers on AWS<\/span>. <\/span>In this final episode we will explain what was going on behind the scenes and discuss the Terraform and Ansible part.<\/span><\/p>\n

1. The Terraform part<\/span><\/h3>\n

The most important files of the <\/span>Terrafo<\/span>r<\/span>m<\/span> code can be broken down into two files<\/span>.<\/span> <\/span><\/p>\n

a. The main.tf file<\/i>.<\/strong><\/span><\/h4>\n

In this file, all things that need to be done by Terraform are configured.<\/span> <\/span><\/p>\n

First<\/span>,<\/span> we need to declare all the variable used in this file.<\/span> <\/span><\/p>\n

variable<\/span> <\/span>\"<\/span>aws_region<\/span>\"<\/span> {}<\/span> <\/span>\n\nvariable<\/span> <\/span>\"profile\"<\/span> {}<\/span> <\/span>\n\nvariable<\/span> <\/span>\"<\/span>server_port<\/span>\"<\/span> {}<\/span> <\/span>\n\nvariable<\/span> <\/span>\"<\/span>key_name<\/span>\"<\/span> {}<\/span> <\/span>\n\nvariable<\/span> <\/span>\"<\/span>public_key<\/span>\"<\/span> {}<\/span> <\/span>\n\nvariable<\/span> <\/span>\"<\/span>private_key<\/span>\"<\/span> {}<\/span> <\/span>\n\nvariable<\/span> <\/span>\"<\/span>aws_access_key_id<\/span>\"<\/span> {}<\/span> <\/span>\n\nvariable<\/span> <\/span>\"<\/span>aws_secret_access_key<\/span>\"<\/span> {}<\/span> <\/span>\n\nvariable<\/span> <\/span>\"<\/span>aws_availability_zone<\/span>\"<\/span> {}<\/span> <\/span>\n\nvariable<\/span> <\/span>\"<\/span>aws_ami_id<\/span>\"<\/span> {}<\/span> \n\n<\/span><\/pre>\n
Let <\/span>Terraform<\/span> know we will use the <\/span>aws<\/span>-provider.<\/span> <\/span><\/p>\n
provider<\/span> <\/span>\"<\/span>aws<\/span>\"<\/span> <\/span>{<\/span> <\/span>\n\n  profile = <\/span>var.profile<\/span> <\/span>\n\n  region = <\/span>var.aws_region<\/span> <\/span>\n\n  <\/span>access_key<\/span> = <\/span>var.aws_access_key_id<\/span> <\/span>\n\n  <\/span>secret_key<\/span> = <\/span>var.aws_secret_access_key<\/span> <\/span>\n\n}<\/span> <\/span><\/pre>\n
Add<\/span> a public key to <\/span>aws<\/span> for ssh access<\/span>.<\/span> <\/span><\/p>\n
resource<\/span> <\/span>\"<\/span>aws_key_pair<\/span>\"<\/span> <\/span>\"deployer\"<\/span> <\/span>{<\/span> <\/span>\n\n  <\/span>key_name<\/span> = <\/span>var.key_name<\/span> <\/span>\n\n  <\/span>public_key<\/span> = <\/span>var.public<\/span>_key<\/span> <\/span>\n\n}<\/span> <\/span><\/pre>\n
C<\/span>onfigure the firewall with some inbound(ingress) and outbound(egress) rules<\/span>.<\/span> <\/span><\/p>\n
resource<\/span> <\/span>\"<\/span>aws_security_group<\/span>\"<\/span> <\/span>\"<\/span>devotest<\/span>\"<\/span> <\/span>{<\/span> <\/span>\n\n  name = \"terraform-example-instance\"<\/span> <\/span>\n\n  ingress {<\/span> <\/span>\n\n    <\/span>from_port<\/span> = <\/span>var.server<\/span>_port<\/span> <\/span>(A variable used as port from the world <\/span><\/b>accessable<\/span><\/b>)<\/span><\/b> <\/span>\n\n    <\/span>to_port<\/span> = <\/span>var.server<\/span>_port<\/span> <\/span>\n\n    protocol = \"<\/span>tcp<\/span>\"<\/span> <\/span>\n\n    <\/span>cidr_blocks<\/span> = [\"0.0.0.0\/0\"]<\/span> <\/span>\n\n  }<\/span> <\/span>\n\n  ingress {<\/span> <\/span>\n\n    <\/span>from_port<\/span> = <\/span>22  <\/span>(<\/span><\/b>Port 22 ingress from the world <\/span><\/b>accessable<\/span><\/b>)<\/span><\/b> <\/span><\/pre>\n
    <\/span>to_port<\/span> = 22<\/span> <\/span>\n\n    protocol = \"<\/span>tcp<\/span>\"<\/span> <\/span>\n\n    <\/span>cidr_blocks<\/span> = [\"0.0.0.0\/0\"]<\/span> <\/span>\n\n  }<\/span> <\/span>\n\n  egress {<\/span> <\/span>\n\n    <\/span>from_port<\/span> = <\/span>80  <\/span>(<\/span><\/b>Port 80 to egress)<\/span><\/b> <\/span>\n\n    <\/span>to_port<\/span> = 80<\/span> <\/span>\n\n    protocol = \"<\/span>tcp<\/span>\"<\/span> <\/span>\n\n    <\/span>cidr_blocks<\/span> = [\"0.0.0.0\/0\"]<\/span> <\/span>\n\n  }<\/span> <\/span>\n\n  egress {<\/span> <\/span>\n\n    <\/span>from_port<\/span> = 443 <\/span>(Port 443 to egress)<\/span><\/b> <\/span>\n\n    <\/span>to_port<\/span> = 443<\/span> <\/span>\n\n    protocol = \"<\/span>tcp<\/span>\"<\/span> <\/span>\n\n    <\/span>cidr_blocks<\/span> = [\"0.0.0.0\/0\"]<\/span> <\/span>\n\n  }<\/span> <\/span>\n\n}<\/span> <\/span><\/pre>\n
We will create <\/span>two<\/span> centos 7.7 machine instance type t<\/span>2.micro<\/span>.<\/span> <\/span>T<\/span>2.micro<\/span> is a machine with 1 vCPU, 6CPU credits\/hour and 1GiB memory. <\/span>The var <\/span>aws_ami_id<\/span> gives us the centos 7.7 machines<\/span>.<\/span> <\/span>One is called <\/span>devotest_web<\/span>, the other <\/span>devotest_db<\/span>.<\/span> <\/span><\/p>\n
resource<\/span> <\/span>\"<\/span>aws_instance<\/span>\"<\/span> <\/span>\"<\/span>devotest_web<\/span>\"<\/span> <\/span>{<\/span> <\/span>\n\n  <\/span>ami<\/span> = <\/span>var.aws_ami_id<\/span> <\/span>\n\n  <\/span>instance_type<\/span> = \"t<\/span>2.micro<\/span>\"<\/span> <\/span>\n\n  <\/span>key_name<\/span> = <\/span>var.key_name<\/span> <\/span>\n\n  <\/span>vpc_security_group_ids<\/span> = [aws_security_group.devotest.id]<\/span> <\/span>\n\n  tags = {<\/span> <\/span>\n\n    Name = \"terraform-<\/span>devotest<\/span>\"<\/span> <\/span>\n\n  }<\/span> <\/span>\n\n  <\/span>root_block_device<\/span> {<\/span> <\/span>\n\n    <\/span>delete_on_termination<\/span> = true <\/span>(Delete also the volume when deleting the instance)<\/span><\/b> <\/span>\n\n  }<\/span> <\/span>\n\n}<\/span> <\/span>\n\nresource<\/span> <\/span>\"<\/span>aws_instance<\/span>\"<\/span> <\/span>\"<\/span>devotest_db<\/span>\"<\/span> <\/span>{<\/span> <\/span><\/pre>\n
  <\/span>ami<\/span> = <\/span>var.aws_ami_id<\/span> <\/span>\n\n  <\/span>instance_type<\/span> = \"t<\/span>2.micro<\/span>\"<\/span> <\/span>\n\n  <\/span>key_name<\/span> = <\/span>var.key_name<\/span> <\/span>\n\n  <\/span>vpc_security_group_ids<\/span> = [aws_security_group.devotest.id]<\/span> <\/span>\n\n  tags = {<\/span> <\/span>\n\n    Name = \"terraform-<\/span>devotest<\/span>\"<\/span> <\/span>\n\n  }<\/span> <\/span>\n\n  <\/span>root_block_device<\/span> {<\/span> <\/span>\n\n    <\/span>delete_on_termination<\/span> = true <\/span>(Delete also the volume when deleting the instance)<\/span><\/b> <\/span>\n\n  }<\/span> <\/span>\n\n}<\/span> <\/span><\/pre>\n
After the deployment of the machines<\/span>,<\/span> <\/span>we want to get back some information as variables<\/span>.<\/span> <\/span><\/p>\n
public_ip_web<\/span><\/b>, the public <\/span><\/b>ip<\/span><\/b> of the <\/span><\/b>webserver.<\/span><\/b> <\/span>\n\noutput<\/span> <\/span>\"<\/span>public_ip_web<\/span>\"<\/span> <\/span>{<\/span> <\/span>\n\nvalue = <\/span>aws_<\/span>instance.devotest<\/span>_web.public_ip<\/span> <\/span>\n\ndescription = \"The public IP of the web server\"<\/span> <\/span>\n\n}<\/span> <\/span><\/pre>\n
name_web<\/span><\/b>, the name of the webserver<\/span><\/b> <\/span>\n\noutput<\/span> <\/span>\"<\/span>name_web<\/span>\"<\/span> <\/span>{<\/span> <\/span>\n\n  value = <\/span>aws_<\/span>instance.devotest<\/span>_web.tags.Name<\/span> <\/span>\n\n  description = \"The Name of the web server\"<\/span> <\/span>\n\n}<\/span> <\/span><\/pre>\n
state_web<\/span><\/b>, the state of the webserver instance<\/span><\/b> <\/span>\n\noutput<\/span> <\/span>\"<\/span>state_web<\/span>\"<\/span> <\/span>{<\/span> <\/span>\n\n  value = <\/span>aws_<\/span>instance.devotest<\/span>_web.instance_state<\/span> <\/span>\n\n  description = \"The state of the web server\"<\/span> <\/span>\n\n}<\/span> <\/span>\n\npublic_ip_db<\/span><\/b>, the <\/span><\/b>ip<\/span><\/b> of the database instance<\/span><\/b> <\/span>\n\noutput<\/span> <\/span>\"<\/span>public_ip_db<\/span>\"<\/span> <\/span>{<\/span> <\/span>\n\n  value = <\/span>aws_<\/span>instance.devotest<\/span>_db.public_ip<\/span> <\/span>\n\n  description = \"The public IP of the <\/span>db<\/span> server\"<\/span> <\/span>\n\n}<\/span> <\/span>\n\nname_db<\/span><\/b>, the name of the database instance<\/span><\/b> <\/span>\n\noutput<\/span> <\/span>\"<\/span>name_db<\/span>\"<\/span> <\/span>{<\/span> <\/span>\n\n  value = <\/span>aws_<\/span>instance.devotest<\/span>_db.tags.Name<\/span> <\/span>\n\n  description = \"The Name of the <\/span>db<\/span> server\"<\/span> <\/span>\n\n}<\/span> <\/span>\n\nstate_de<\/span><\/b>, the state of the database instance<\/span><\/b> <\/span>\n\noutput<\/span> <\/span>\"<\/span>state_db<\/span>\"<\/span> <\/span>{<\/span> <\/span>\n\n  value = <\/span>aws_<\/span>instance.devotest<\/span>_db.instance_state<\/span> <\/span>\n\n  description = \"The state of the <\/span>db<\/span> server\"<\/span> <\/span>\n\n}<\/span><\/pre>\n
b. Theterraform.tfvarsfile.<\/h4>\n
This file will be created from an Ansible template which makes it possible to pass Ansible variables to the <\/span>Terraform<\/span> part.<\/span><\/p>\n
This is the content of the <\/span>roles\/terra-provision\/templates\/terraform.tfvars.j<\/span>2 file, the template used to create the terraform\/<\/span>terraform.tfvars<\/span> file. The variables between \u201c<\/span>{{ }<\/span>}\u201d are Ansible variables and will be replaced with the values from <\/span>group_vars<\/span>\/all\/<\/span>vars.yml<\/span> and <\/span>group_vars<\/span>\/all\/<\/span>vault.yml<\/span>.<\/span> <\/span><\/p>\n
# the location of the private key for connection to the servers<\/span> <\/span>\n\nprivate_key<\/span> =\"~\/ansible-terraform-keys\/<\/span>id_rsa<\/span>\"<\/span> <\/span>\n\nserver_port<\/span> = 80<\/span> <\/span>\n\nkey_name<\/span> = \"<\/span>aws_deployer<\/span>\"<\/span> <\/span>\n# public key, <\/span>aws_access_key_id<\/span>, <\/span>aws_secret_access_key<\/span> will be overwritten from ansible vault var<\/span> <\/span>\n\npublic_key<\/span> = \"<\/span>{{ <\/span>public<\/span>_key<\/span> }}\"<\/span> <\/span>\n\naws_access_key_id<\/span> = \"<\/span>{{ <\/span>aws<\/span>_access_key_id<\/span> }}\"<\/span> <\/span>\n\naws_secret_access_key<\/span> = \"<\/span>{{ <\/span>aws<\/span>_secret_access_key<\/span> }}\"<\/span> <\/span>\n\nprofile = \"<\/span>{{ <\/span>aws<\/span>_profile<\/span> }}\"<\/span> <\/span>\n\n# <\/span>aws_ami_id<\/span>, <\/span>aws_region<\/span> will be overwritten from ansible var<\/span> <\/span>\n\naws_ami_id<\/span> = \"<\/span>{{ <\/span>aws<\/span>_ami_id<\/span> }}\"<\/span> <\/span>\n\naws_region<\/span> = \"eu-west-1\"<\/span> <\/span>\n\naws_availability_zone<\/span> = \"eu-west-1a\"<\/span> <\/span><\/pre>\n
2. The Ansible part.<\/span><\/h3>\n
The job of Ansible playbook is divided into 3 plays.<\/span> <\/span><\/p>\n
a. First play use Terraform to deploy the machines<\/span><\/i><\/b>.<\/span><\/span><\/h4>\n
- <\/span>hosts<\/span>: <\/span>localhost  <\/span>(<\/span><\/b>we run this playbook on our local machine)<\/span><\/b> \n<\/span>  connection<\/span>: <\/span>local<\/span> <\/span>\n\n  <\/span>gather_facts<\/span>: <\/span>no<\/span> <\/span>\n\n  tasks<\/span>: <\/span>The different tasks follow after this parameter.<\/span><\/b> <\/span><\/pre>\n
First task:<\/span> <\/span>we create the variable file for Terraform from a template (see above)<\/span>.<\/span> This <\/span>can<\/span> be done via<\/span> <\/span>the terra-provision role.<\/span> <\/span><\/p>\n
  - <\/span>name<\/span>: <\/span>create <\/span>teraform.tfvars<\/span> <\/span>\n\n    <\/span>include_role<\/span>:<\/span> <\/span>\n\n    name<\/span>: <\/span>terra-provision<\/span> <\/span><\/pre>\n
If the <\/span>T<\/span>erraform does not exist<\/span>,<\/span> we run <\/span>the <\/span>Terrafrom<\/span> <\/span>init<\/span> command to initialise <\/span>T<\/span>erraform<\/span>. <\/span> <\/span><\/p>\n
  - <\/span>name<\/span>: <\/span>init<\/span> the terraform <\/span>if .terraform<\/span> is not there<\/span> <\/span>\n\n    shell<\/span>: <\/span>terraform <\/span>init<\/span> <\/span>\n\n    <\/span>args<\/span>:<\/span> <\/span>\n\n    <\/span>chdir<\/span>: <\/span>\"<\/span>{{ <\/span>playbook<\/span>_dir<\/span> }}\/terraform\/\"<\/span> <\/span>\n\n    creates<\/span>: <\/span>\"<\/span>{{ <\/span>playbook<\/span>_dir<\/span> }}\/terraform\/.terraform\/\"<\/span> <\/span><\/pre>\n
We run the Terraform script. This will read the terraform\/main.tf file and deploys whatever is configured.<\/span> <\/span><\/p>\n
- <\/span>name<\/span>: <\/span>run the terraform script<\/span> <\/span>\n\n  terraform<\/span>:<\/span> <\/span>\n\n    <\/span>project_path<\/span>: <\/span>\"<\/span>{{ <\/span>playbook<\/span>_dir<\/span> }}\/terraform\/\"<\/span> <\/span>\n\n    state<\/span>: <\/span>\"<\/span>{{ <\/span>aws<\/span>_instance_state<\/span> }}\"<\/span> <\/span>\n\n    variables<\/span>:<\/span> <\/span>\n\n    <\/span>aws_region<\/span>: <\/span>\"<\/span>{{ <\/span>aws<\/span>_region<\/span> }}\"<\/span> <\/span>\n\n    <\/span>aws_access_key_id<\/span>: <\/span>\"<\/span>{{ <\/span>aws<\/span>_access_key_id<\/span> }}\"<\/span> <\/span>\n\n    <\/span>aws_secret_access_key<\/span>: <\/span>\"<\/span>{{ <\/span>aws<\/span>_secret_access_key<\/span> }}\"<\/span> <\/span>\n\n    <\/span>aws_ami_id<\/span>: <\/span>\"<\/span>{{ <\/span>aws<\/span>_ami_id<\/span> }}\"<\/span> <\/span>\n\n    <\/span>public_key<\/span>: <\/span>\"<\/span>{{ <\/span>public<\/span>_key<\/span> }}\"<\/span> <\/span>\n\n    register<\/span>: <\/span>terra_result<\/span> <\/span>(The output will be added to the <\/span><\/b>terra_result<\/span><\/b> variable)<\/span><\/b> <\/span><\/pre>\n
For debug we show the result from the previous <\/span>T<\/span>erraform command.<\/span> <\/span><\/p>\n
- <\/span>name<\/span>: <\/span>show <\/span>terra_result<\/span> <\/span>\n\n  debug<\/span>:<\/span> <\/span>\n\n  var<\/span>: <\/span>terra_result<\/span> <\/span><\/pre>\n
Out of the result<\/span>,<\/span> we retrieve the <\/span>ip<\/span> address form the web- and database<\/span> <\/span>server.<\/span> <\/span><\/p>\n
- <\/span>name<\/span>: <\/span>set <\/span>vm_ip<\/span> \/ name<\/span> <\/span>\n\n  <\/span>set_fact<\/span>:<\/span> <\/span>\n\n    <\/span>vm_ip_web<\/span>: <\/span>\"<\/span>{{ <\/span>terra<\/span>_result.outputs.public_ip_web.value<\/span> }}\"<\/span> <\/span>\n\n    <\/span>vm_ip_db<\/span>: <\/span>\"<\/span>{{ <\/span>terra<\/span>_result.outputs.public_ip_db.value<\/span> }}\"<\/span> <\/span>\n\n  when<\/span>:<\/span> <\/span>\n\n    - <\/span>terra_<\/span>result.outputs<\/span>.state_web<\/span> is defined<\/span> <\/span>\n\n- <\/span>terra_<\/span>result.outputs<\/span>.state_db<\/span> is defined<\/span> <\/span><\/pre>\n
In the next block<\/span>,<\/span> we create a dynamic inventory from the <\/span>T<\/span>erraform result, the <\/span>ip\u2019s<\/span> will be stored in the <\/span>A<\/span>nsible inventory so it can be used in the next plays.<\/span> <\/span>We create an inventory for the webserver and another for the <\/span>database server<\/span>.<\/span> <\/span><\/p>\n
- <\/span>name<\/span>: <\/span>create the dynamic inventory<\/span> <\/span>\n\n  block<\/span>:<\/span> <\/span>\n\n    - <\/span>name<\/span>: <\/span>remove old dynamic <\/span>group_vars<\/span> file<\/span> <\/span>\n\n      file<\/span>:<\/span> <\/span>\n\n        path<\/span>: <\/span>\"<\/span>{{ item<\/span> }}\"<\/span> <\/span>\n\n        state<\/span>: <\/span>absent<\/span> <\/span>\n\n      <\/span>with_items<\/span>:<\/span> <\/span>\n\n        - <\/span>group_vars<\/span>\/<\/span>dynamic_web.yml<\/span> <\/span>\n\n        - <\/span>group_vars<\/span>\/<\/span>dynamic_db.yml<\/span> <\/span>\n\n  - <\/span>name<\/span>: <\/span>create new centos <\/span>group_vars<\/span> file<\/span> <\/span>\n\n      file<\/span>:<\/span> <\/span>\n\n        path<\/span>: <\/span>\"<\/span>{{ item<\/span> }}\"<\/span> <\/span>\n\n        state<\/span>: <\/span>touch<\/span> <\/span>\n\n    <\/span>with_items<\/span>:<\/span> <\/span>\n\n      - <\/span>group_vars<\/span>\/<\/span>dynamic_web.yml<\/span> <\/span>\n\n      - <\/span>group_vars<\/span>\/<\/span>dynamic_db.yml<\/span> <\/span>\n\n- <\/span>name<\/span>: <\/span>create the inventory directory<\/span> <\/span>\n\n  file<\/span>:<\/span> <\/span>\n\n    path<\/span>: <\/span>inventory\/<\/span> <\/span>\n\n    state<\/span>: <\/span>directory<\/span> <\/span><\/pre>\n
- <\/span>name<\/span>: <\/span>remove old dynamic host file<\/span> <\/span>\n\n  file<\/span>:<\/span> <\/span>\n\n    path<\/span>: <\/span>inventory\/hosts<\/span> <\/span>\n\n    state<\/span>: <\/span>absent<\/span> <\/span>\n\n- <\/span>name<\/span>: <\/span>create new dynamic host file<\/span> <\/span>\n\n  file<\/span>:<\/span> <\/span>\n\n    path<\/span>: <\/span>inventory\/hosts<\/span> <\/span><\/pre>\n
    state<\/span>: <\/span>touch<\/span> <\/span>\n\n- <\/span>name<\/span>: <\/span>add retrieved IP to file<\/span> <\/span>\n\n  <\/span>blockinfile<\/span>:<\/span> <\/span>\n\n    path<\/span>: <\/span>group_vars<\/span>\/<\/span>dynamic_web.yml<\/span> <\/span>\n\n    marker<\/span>: <\/span>\"\"<\/span> <\/span>\n\n    block<\/span>: <\/span>|<\/span> <\/span>\n\n        ---<\/span> <\/span><\/pre>\n
        <\/span>ansible_host<\/span>: <\/span>{{ <\/span>vm<\/span>_ip_web<\/span> }}<\/span> <\/span>\n\n        <\/span>ansible_user<\/span>: <\/span>{{ <\/span>remote<\/span>_user<\/span>[hypervisor] }}<\/span> <\/span>\n\n        <\/span>become_user<\/span>: <\/span>{{ <\/span>remote<\/span>_user<\/span>[hypervisor] }}<\/span> <\/span>\n\n        <\/span>remote_user<\/span>: <\/span>{{ <\/span>remote<\/span>_user<\/span>[hypervisor] }}<\/span> <\/span>\n\n        <\/span>become:<\/span> true<\/span> <\/span><\/pre>\n
- <\/span>name<\/span>: <\/span>add retrieved IP to file<\/span> <\/span>\n\n  <\/span>blockinfile<\/span>:<\/span> <\/span>\n\n    path<\/span>: <\/span>group_vars<\/span>\/<\/span>dynamic_db.yml<\/span> <\/span>\n\n    marker<\/span>: <\/span>\"\"<\/span> <\/span>\n\n    block<\/span>: <\/span>|<\/span> <\/span>\n\n        ---<\/span> <\/span>\n\n        <\/span>ansible_host<\/span>: <\/span>{{ <\/span>vm<\/span>_ip_db<\/span> }}<\/span> <\/span>\n\n        <\/span>ansible_user<\/span>: <\/span>{{ <\/span>remote<\/span>_user<\/span>[hypervisor] }}<\/span> <\/span>\n\n        <\/span>become_user<\/span>: <\/span>{{ <\/span>remote<\/span>_user<\/span>[hypervisor] }}<\/span> <\/span>\n\n        <\/span>remote_user<\/span>: <\/span>{{ <\/span>remote<\/span>_user<\/span>[hypervisor] }}<\/span> <\/span>\n\n        <\/span>become:<\/span> true<\/span> <\/span>\n\n        ...<\/span> \n<\/span>\n- <\/span>name<\/span>: <\/span>add retrieved IP to file<\/span> <\/span>\n\n  <\/span>blockinfile<\/span>:<\/span> <\/span>\n\n    path<\/span>: <\/span>\"inventory\/hosts\"<\/span> <\/span>\n\n    marker<\/span>: <\/span>\"\"<\/span> <\/span>\n\n    block<\/span>: <\/span>|<\/span> <\/span>\n\n        [<\/span>dynamic_web<\/span>]<\/span> <\/span>\n\n        <\/span>{{ <\/span>vm<\/span>_ip_web<\/span> }}<\/span> <\/span>\n        <\/span> <\/span>\n\n        [<\/span>dynamic_db<\/span>]<\/span> <\/span>\n\n        <\/span>{{ <\/span>vm<\/span>_ip_db<\/span> }}<\/span> <\/span>\n        <\/span> <\/span><\/pre>\n
- <\/span>name<\/span>: <\/span>Add host<\/span> <\/span>\n\n  <\/span>add_host<\/span>:<\/span> <\/span>\n\n    hostname<\/span>: <\/span>\"<\/span>{{ <\/span>vm<\/span>_ip_web<\/span> }}\"<\/span> <\/span>\n\n    <\/span>groupname<\/span>: <\/span>dynamic_web<\/span> <\/span>\n\n    <\/span>remote_user<\/span>: <\/span>\"<\/span>{{ <\/span>remote<\/span>_user<\/span>[hypervisor] }}\"<\/span> <\/span>\n\n- <\/span>name<\/span>: <\/span>Add host<\/span> <\/span>\n\n  <\/span>add_host<\/span>:<\/span> <\/span>\n\n    hostname<\/span>: <\/span>\"<\/span>{{ <\/span>vm<\/span>_ip_db<\/span> }}\"<\/span> <\/span>\n\n    <\/span>groupname<\/span>: <\/span>dynamic_db<\/span> <\/span>\n\n    <\/span>remote_user<\/span>: <\/span>\"<\/span>{{ <\/span>remote<\/span>_user<\/span>[hypervisor] }}\"<\/span> <\/span>\n\n  when<\/span>:<\/span> <\/span><\/pre>\n
    - <\/span>terra_<\/span>result.outputs<\/span>.state_web<\/span> is defined<\/span> <\/span>\n\n    - <\/span>terra_<\/span>result.outputs<\/span>.state_db<\/span> is defined<\/span> <\/span>\n\n\n- <\/span>name<\/span>: <\/span>Collect facts again<\/span> <\/span>\n\n  setup<\/span>:<\/span> <\/span><\/pre>\n
As a last step<\/span><\/i>,<\/span><\/i> we will check if we can access the webserver via ssh.<\/span><\/i> <\/span><\/p>\n
################################<\/span> <\/span>\n\n# pause #<\/span> <\/span>\n\n################################<\/span> <\/span>\n\n- <\/span>name<\/span>: <\/span>Wait 300 seconds for port 22 to become open and contains the string \"OpenSSH\"<\/span> <\/span>\n\n  <\/span>wait_for<\/span>:<\/span> <\/span>\n\n  port<\/span>: <\/span>22<\/span> <\/span>\n\n  host<\/span>: <\/span>'<\/span>{{ <\/span>vm<\/span>_ip_web<\/span> }}'<\/span> <\/span>\n\n  <\/span>search_regex<\/span>: <\/span>OpenSSH<\/span> <\/span>\n\n  delay<\/span>: <\/span>10<\/span> <\/span>\n\n  vars<\/span>:<\/span> <\/span>\n\n  <\/span>ansible_connection<\/span>: <\/span>local<\/span> <\/span>\n\nwhen<\/span>: <\/span>vm_ip_web<\/span> is defined<\/span> <\/span><\/pre>\n
b. A second play installs the software on the webserver, configure it and start it.<\/span><\/i><\/b><\/span><\/h4>\n
Use the dynamic_web inventory<\/p>\n
- <\/span>hosts<\/span>: <\/span>dynamic_web<\/span> <\/span><\/pre>\n
Load the role webserver.<\/p>\n
  tasks<\/span>:<\/span> <\/span>\n\n    - <\/span>name<\/span>: <\/span>create a website<\/span> <\/span>\n\n      <\/span>include_role<\/span>:<\/span> <\/span>\n\n      name<\/span>: <\/span>webserver<\/span> <\/span><\/pre>\n
The content of the webserver role can be found in roles\/webserver\/tasks\/main.yml<\/p>\n
You will see that this role does a yum update (which can take some time), installs the apache webserver (httpd), creates a website configuration file in \u2018\/etc\/httpd\/conf.d\/\u2019, creates a html page to serve, and finally restarts the webserver.<\/p>\n
This was the last episode of the Ansible Terraform series<\/a>. You can try to extend the code by trying the following:<\/p>\n