Using host vars and group vars

Updated Dec 21, 2020 ·

Overview

This lab organizes user and host configuration with host_vars and group_vars so inventory data stays easier to maintain.

Diagram:

This is a continuation of the previous lab. We'll also still be using the same files in project one from the first 10 labs. To recap, here is a tree-output of our project one:

Project One in tree-output

ansible.cfg

 [defaults]
# E: variables for my personal lab
inventory = ~/proj-ansible-1/one/inventories/edendev.inv
remote_user = eden
private_key_file = ~/.ssh/id_rsa
host_key_checking = False
retry_files_enabled = False
timeout = 24
gather_facts = smart

#ansible_managed = "# This file is managed by Ansible, all local changes will be lost !"
#allow_world_readable_tmpfiles = True
#precedence = all_plugins_play, all_inventory, groups_plugins_play, groups_inventory, all_plugins_inventory, groups_plugins_inventory
#any_errors_fatal = True
#timeout = 24

[privilege_escalation]
#become_method = sudo
#become=True
#become_user=root
#become_ask_pass=False

[paramiko_connection]
#record_host_keys = False

[ssh_connection]
scp_if_ssh = True
pipelining = True

inventories/edendev.inv

[webservers]
app1    ansible_host=13.251.146.254
app2    ansible_host=122.248.203.239
app3    ansible_host=52.76.189.254
app4    ansible_host=54.255.28.202

[loadbalancers]
lb1     ansible_host=13.228.99.157

[local]
localhost   ansible_connection=local

symlink in root directory pointing to projects folder

$ ls -la | grep "\->"
lrwxrwxrwx  1 joseeden joseeden    70 Jan 14 23:03 proj-ansible-1 -> /mnt/c/Users/Eden Jose/4-Projects

In this lab, we'll first create host_vars and group_vars inside the playbooks folder. We'll then create the webservers and loadbalancers file inside the group_vars folder.

$ mkdir playbooks/group_vars
$ mkdir playbooks/host_vars
$ touch playbooks/group_vars/webservers
$ touch playbooks/group_vars/loadbalancers 

Our current playbooks folder shold now look like this:

joseeden@EdenJose:playbooks$ tree
.
├── create-users-vars.yml
├── create-users-vars2.yml
├── create-users.yml
├── group_vars
│   ├── loadbalancers
│   └── webservers
├── host_vars 

We'll then modify the create-users-vars2.yml from the previous lab. Here is what it currently looks like:

create-users-vars2.yml

# create-users-vars2.yml
---

- name: Create users on the webservers
  hosts: webservers
  become: true
  vars:
    username:
      testeden-3:
        uname: testeden-3
        description: ansible-created-user-3
  tasks:
  - name: Create the users
    user:
      name: "{{ username['testeden-3']['uname']}}"
      state: present
      comment: "{{ username['testeden-3']['description'] }}"

We'll remove the username section and put them in the group_vars/webservers file. Also, change the user to testeden-4.

# Variables for the webservers group

username:
    testeden-4:
        uname: testeden-4
        description: ansible-created-user-4

We'll create a copy of the playbook and rename it to create-users-vars3.yml. After removing the variables, here's what it looks like now.

# create-users-vars3.yml
---

- name: Create users on the webservers
  hosts: webservers
  become: true
  tasks:
  - name: Create the users
    user:
      name: "{{ username['testeden-4']['uname']}}"
      state: present
      comment: "{{ username['testeden-4']['description'] }}"

Running the playbook.

$ ansible-playbook playbooks/create-users-vars3.yml

Now to make sure the users were really created, let's login again to two of the four webservers and check.

$ ssh eden@tstsvr1
Last login: Fri Jan 14 22:37:13 2022 from 1.2.3.4
[eden@tstsvr1 ~]$
[eden@tstsvr1 ~]$ tail -4 /etc/passwd
testeden-1:x:1001:1001:ansible-created-user-1:/home/testeden-1:/bin/bash
testeden-2:x:1002:1002:ansible-created-user-2:/home/testeden-2:/bin/bash
testeden-3:x:1003:1003:ansible-created-user-3:/home/testeden-3:/bin/bash
testeden-4:x:1004:1004:ansible-created-user-4:/home/testeden-4:/bin/bash  

$ ssh eden@tstsvr3
Last login: Fri Jan 14 22:50:08 2022 from 1.2.3.4
[eden@tstsvr3 ~]$
[eden@tstsvr3 ~]$ tail -4 /etc/passwd
testeden-1:x:1001:1001:ansible-created-user-1:/home/testeden-1:/bin/bash
testeden-2:x:1002:1002:ansible-created-user-2:/home/testeden-2:/bin/bash
testeden-3:x:1003:1003:ansible-created-user-3:/home/testeden-3:/bin/bash
testeden-4:x:1004:1004:ansible-created-user-4:/home/testeden-4:/bin/bash 

Overview​

Overview