Complete Guide: Installing Ansible and Java 8 on Ubuntu 20.04

Published: at 10:00 AM

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Overview

This guide provides detailed instructions for installing and configuring Ansible and Java 8 on Ubuntu 20.04. Whether you’re setting up a development environment or preparing for automation tasks, this guide covers everything from basic installation to advanced configuration.

System Architecture

graph TB
    subgraph "Control Node"
        A[Ansible Control Node]
        B[Java 8 Runtime]
        C[SSH Keys]
    end

    subgraph "Managed Nodes"
        D[Node 1]
        E[Node 2]
        F[Node N]
    end

    subgraph "Configuration"
        G[Inventory File]
        H[Playbooks]
        I[Variables]
    end

    A --> D
    A --> E
    A --> F
    A --> G
    G --> H
    H --> I
    C --> D
    C --> E
    C --> F

    style A fill:#4ecdc4,stroke:#087f5b,stroke-width:2px
    style B fill:#ffd43b,stroke:#fab005,stroke-width:2px
    style G fill:#74c0fc,stroke:#1971c2,stroke-width:2px

Prerequisites

Before proceeding, ensure you have:

Installing Ansible

Step 1: Update System Packages

# Update package index
sudo apt update

# Upgrade existing packages
sudo apt upgrade -y

# Install software properties common
sudo apt install -y software-properties-common

Step 2: Add Ansible Repository

# Add official Ansible PPA
sudo apt-add-repository ppa:ansible/ansible

# Update package index again
sudo apt update

Step 3: Install Ansible

# Install Ansible
sudo apt install -y ansible

# Verify installation
ansible --version

# Check Python version (Ansible requires Python)
python3 --version

Step 4: Configure Ansible User

# Create dedicated Ansible user
sudo useradd -m ansible
sudo passwd ansible

# Add to sudo group
sudo usermod -aG sudo ansible

# Configure sudoers for passwordless sudo
echo "ansible ALL=(ALL) NOPASSWD: ALL" | sudo tee /etc/sudoers.d/ansible

Setting Up SSH Keys

Generate SSH Keys

# Switch to ansible user
sudo su - ansible

# Generate SSH key pair
ssh-keygen -t rsa -b 4096 -C "ansible@control-node"

# View public key
cat ~/.ssh/id_rsa.pub

Distribute SSH Keys to Managed Nodes

# Copy SSH key to managed nodes
ssh-copy-id ansible@managed-node-ip

# Test SSH connection
ssh ansible@managed-node-ip

# For multiple nodes, use a loop
for host in node1 node2 node3; do
    ssh-copy-id ansible@$host
done

Configuring Ansible Inventory

Edit Inventory File

# Create custom inventory directory
sudo mkdir -p /etc/ansible/inventories/production

# Edit inventory file
sudo nano /etc/ansible/inventories/production/hosts

Add the following content:

[web_servers]
web1 ansible_host=192.168.1.10 ansible_user=ansible
web2 ansible_host=192.168.1.11 ansible_user=ansible

[db_servers]
db1 ansible_host=192.168.1.20 ansible_user=ansible
db2 ansible_host=192.168.1.21 ansible_user=ansible

[all:vars]
ansible_python_interpreter=/usr/bin/python3
ansible_ssh_common_args='-o StrictHostKeyChecking=no'

[web_servers:vars]
http_port=80
max_clients=200

[db_servers:vars]
mysql_port=3306
max_connections=100

Ansible Configuration File

Create or edit /etc/ansible/ansible.cfg:

[defaults]
inventory = /etc/ansible/inventories/production/hosts
remote_user = ansible
host_key_checking = False
retry_files_enabled = False
gathering = smart
fact_caching = jsonfile
fact_caching_connection = /tmp/ansible_facts_cache
fact_caching_timeout = 86400

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

[ssh_connection]
ssh_args = -C -o ControlMaster=auto -o ControlPersist=60s
pipelining = True

Installing Java 8

Step 1: Install OpenJDK 8

# Update package index
sudo apt update

# Install OpenJDK 8 JDK (includes JRE)
sudo apt install -y openjdk-8-jdk

# Verify installation
java -version
javac -version

Step 2: Configure Java Environment

# Set JAVA_HOME environment variable
echo 'export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64' >> ~/.bashrc
echo 'export PATH=$PATH:$JAVA_HOME/bin' >> ~/.bashrc

# Reload bashrc
source ~/.bashrc

# Verify environment variables
echo $JAVA_HOME

Step 3: Manage Multiple Java Versions

# Check all installed Java versions
sudo update-alternatives --list java

# Configure default Java version
sudo update-alternatives --config java

# Configure default javac version
sudo update-alternatives --config javac

Testing the Installation

Test Ansible Connection

# Ping all hosts
ansible all -m ping

# Ping specific group
ansible web_servers -m ping

# Run ad-hoc command
ansible all -a "uname -a"

# Check disk space on all hosts
ansible all -m shell -a "df -h"

Create Test Playbook

Create test-playbook.yml:

---
- name: Test Playbook
  hosts: all
  gather_facts: yes
  tasks:
    - name: Display system information
      debug:
        msg: "{{ ansible_hostname }} - {{ ansible_distribution }} {{ ansible_distribution_version }}"

    - name: Check Java installation
      command: java -version
      register: java_version
      ignore_errors: yes

    - name: Display Java version
      debug:
        msg: "Java is installed: {{ java_version.stderr }}"
      when: java_version.rc == 0

    - name: Ensure Apache is installed (web servers only)
      apt:
        name: apache2
        state: present
      when: inventory_hostname in groups['web_servers']

Run the playbook:

# Run playbook
ansible-playbook test-playbook.yml

# Run with verbose output
ansible-playbook -vvv test-playbook.yml

# Run with check mode (dry run)
ansible-playbook --check test-playbook.yml

Test Java Installation

Create HelloWorld.java:

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello from Java " + System.getProperty("java.version"));
        System.out.println("Running on " + System.getProperty("os.name"));
    }
}

Compile and run:

# Compile
javac HelloWorld.java

# Run
java HelloWorld

Advanced Configuration

Ansible Vault for Secrets

# Create encrypted variables file
ansible-vault create group_vars/all/vault.yml

# Edit encrypted file
ansible-vault edit group_vars/all/vault.yml

# Use in playbook
ansible-playbook playbook.yml --ask-vault-pass

Dynamic Inventory Script

Create dynamic_inventory.py:

#!/usr/bin/env python3
import json
import argparse

def get_inventory():
    inventory = {
        'web_servers': {
            'hosts': ['web1', 'web2'],
            'vars': {
                'http_port': 80
            }
        },
        '_meta': {
            'hostvars': {
                'web1': {
                    'ansible_host': '192.168.1.10'
                },
                'web2': {
                    'ansible_host': '192.168.1.11'
                }
            }
        }
    }
    return inventory

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('--list', action='store_true')
    parser.add_argument('--host', action='store')
    args = parser.parse_args()

    if args.list:
        print(json.dumps(get_inventory()))
    elif args.host:
        print(json.dumps({}))

Make it executable and test:

chmod +x dynamic_inventory.py
ansible -i dynamic_inventory.py all -m ping

Security Best Practices

SSH Security

# Configure SSH daemon
sudo nano /etc/ssh/sshd_config

# Recommended settings:
PermitRootLogin no
PasswordAuthentication no
PubkeyAuthentication yes
AllowUsers ansible

Ansible Security

graph TD
    A[Security Measures] --> B[SSH Keys]
    A --> C[Ansible Vault]
    A --> D[Limited Sudo]
    A --> E[Network Segmentation]

    B --> F[4096-bit RSA]
    B --> G[Passphrase Protected]

    C --> H[Encrypted Passwords]
    C --> I[Encrypted Variables]

    D --> J[Specific Commands]
    D --> K[No Password Required]

    E --> L[Firewall Rules]
    E --> M[VPN Access]

    style A fill:#ff6b6b,stroke:#c92a2a,stroke-width:2px
    style B fill:#74c0fc,stroke:#1971c2,stroke-width:2px
    style C fill:#74c0fc,stroke:#1971c2,stroke-width:2px

Troubleshooting

Common Issues and Solutions

  1. SSH Connection Refused

    # Check SSH service
sudo systemctl status ssh

# Check firewall
sudo ufw status

  2. Python Interpreter Not Found

    # Install Python on managed node
ansible node -m raw -a "apt update && apt install -y python3"

  3. Java Command Not Found

    # Update alternatives
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/java-8-openjdk-amd64/bin/java 1

Debug Commands

# Verbose Ansible output
ansible-playbook playbook.yml -vvvv

# Check Ansible configuration
ansible-config dump

# List all facts
ansible hostname -m setup

Performance Optimization

Ansible Performance Tips

# ansible.cfg optimizations
[defaults]
forks = 20
poll_interval = 15
strategy = free
gathering = smart
fact_caching = jsonfile
fact_caching_connection = /tmp
fact_caching_timeout = 86400

[ssh_connection]
pipelining = True
control_path = /tmp/ansible-%%h-%%p-%%r

Java Performance Tuning

# Set Java heap size
export JAVA_OPTS="-Xms512m -Xmx2048m"

# Enable G1 garbage collector
export JAVA_OPTS="$JAVA_OPTS -XX:+UseG1GC"

Monitoring and Maintenance

Monitoring Script

#!/bin/bash
# monitor-ansible.sh

echo "=== Ansible Status ==="
ansible --version

echo -e "\n=== Reachable Hosts ==="
ansible all -m ping --one-line

echo -e "\n=== Java Version on Hosts ==="
ansible all -m shell -a "java -version 2>&1 | head -1" --one-line

echo -e "\n=== System Resources ==="
ansible all -m shell -a "free -h && df -h /" --one-line

Conclusion

You now have a fully configured Ubuntu 20.04 system with Ansible and Java 8 installed. This setup provides:

Key takeaways:

This foundation enables you to automate infrastructure management, deploy applications, and maintain consistent environments across your systems.