Deploying a Multi-Node Ansible Cluster and Grouping Hosts

Module 5: Ansible Assignment - 5

Tasks To Be Performed:

1. Create a new deployment of Ansible cluster of 5 nodes
2. Label 2 nodes as test and other 2 as prod
3. Install Java on test nodes
4. Install MySQL server on prod nodes

Use Ansible roles for the above and group the hosts under test and prod.

Step 1: Inventory File §

I start by updating the inventory file inventory.ini from Assignment 1 – Ansible to define the nodes and their respective groups.

[all:vars]
ansible_user=ubuntu
 
[test]
slave1 ansible_host=10.0.1.65 
slave2 ansible_host=10.0.1.233
 
[prod]
slave3 ansible_host=10.0.1.210
slave4 ansible_host=10.0.1.85
 
[other]
slave5 ansible_host=10.0.1.211

%%I make sure to replace my_ssh_user with the username that I have SSH access with, and ip_of_x with the actual IP addresses of my nodes.

Using ping Pinging nodes Setup SSH .pem %%

Step 2: Create a Playbook §

I create a playbook named setup.yml. Inside, I define the tasks for each group directly:

---
- hosts: test
  become: yes
  tasks:
  - name: Update the apt cache
    apt:
      update_cache: yes
    changed_when: false
 
  - name: Install default JDK
    apt:
      name: default-jdk
      state: present
 
- hosts: prod
  become: yes
  tasks:
  - name: Update the apt cache
    apt:
      update_cache: yes
    changed_when: false
 
  - name: Install MySQL server
    apt:
      name: mysql-server
      state: present

Step 3: Execute the Playbook §

I run the playbook with the following command:

ansible-playbook -i inventory.ini setup.yml

This will apply the Java installation tasks to the test nodes and the MySQL installation tasks to the prod nodes.

Step 4: Verify the Installations §

#I verify Java installation on test nodes:
ansible test -i inventory.ini -m shell -a "java -version"
 
#And I check MySQL installation on prod nodes:
ansible prod -i inventory.ini -m shell -a "mysql --version"

Success

These commands will give me the version output for Java and MySQL, confirming that the installations are successful on the respective nodes.

Warning

The versions of Java differ because I had previously installed Java manually on Slave1, which explains why the playbook output indicates that no changes were made. Shown as change=0.