infra-automation/cheatsheets/roles/system_info.md

System Info Role Cheatsheet

Quick reference guide for the system_info role - comprehensive system information gathering.

Quick Start

# Run complete information gathering
ansible-playbook site.yml -t system_info

# Run on specific hosts
ansible-playbook site.yml -l webservers -t system_info

# Run with validation only
ansible-playbook site.yml -t system_info,validate

Common Execution Patterns

Full Execution

# All hosts, all information
ansible-playbook site.yml -t system_info

# Single host
ansible-playbook site.yml -l hostname.example.com -t system_info

# Specific group
ansible-playbook site.yml -l production -t system_info

Selective Information Gathering

# CPU information only
ansible-playbook site.yml -t system_info,cpu

# GPU information only
ansible-playbook site.yml -t system_info,gpu

# Memory and swap only
ansible-playbook site.yml -t system_info,memory

# Disk information only
ansible-playbook site.yml -t system_info,disk

# Network information only
ansible-playbook site.yml -t system_info,network

# Hypervisor detection only
ansible-playbook site.yml -t system_info,hypervisor

# System information only
ansible-playbook site.yml -t system_info,system

Combined Tags

# CPU, Memory, and Disk
ansible-playbook site.yml -t system_info,cpu,memory,disk

# Skip installation, gather only
ansible-playbook site.yml -t system_info --skip-tags install

# Validation and health check
ansible-playbook site.yml -t system_info,validate,health-check

# Export statistics only (requires prior gathering)
ansible-playbook site.yml -t system_info,export

Available Tags

Tag	Description
system_info	Main role tag (required)
install	Install required packages
gather	All information gathering
system	OS and system info
cpu	CPU details
gpu	GPU detection
memory	RAM and swap
disk	Storage and filesystems
network	Network interfaces
hypervisor	Virtualization detection
export	Export to JSON
statistics	Statistics aggregation
validate	Validation checks
health-check	Health monitoring
security	Security-related info

Common Variables

Directory Configuration

# Custom statistics directory
system_info_stats_base_dir: /var/lib/ansible/stats

# Disable automatic directory creation
system_info_create_stats_dir: false

Feature Toggles

# Disable GPU gathering (for servers without GPU)
system_info_gather_gpu: false

# Disable hypervisor detection
system_info_detect_hypervisor: false

# Minimal gathering (CPU, Memory, Disk only)
system_info_gather_network: false
system_info_gather_gpu: false
system_info_detect_hypervisor: false

Output Configuration

# Increase JSON readability
system_info_json_indent: 4

# Include raw command outputs
system_info_include_raw_output: true

Output Files

Default Location

./stats/machines/<fqdn>/
├── system_info.json           # Latest statistics
├── system_info_<epoch>.json   # Timestamped backup
└── summary.txt                 # Human-readable summary

View Statistics

# View JSON (pretty-printed)
jq . ./stats/machines/server01.example.com/system_info.json

# View summary
cat ./stats/machines/server01.example.com/summary.txt

# Extract specific information
jq '.cpu.model' ./stats/machines/*/system_info.json
jq '.memory.total_mb' ./stats/machines/*/system_info.json
jq '.hypervisor.is_hypervisor' ./stats/machines/*/system_info.json

# Count hypervisors
jq -r 'select(.hypervisor.is_hypervisor == true) | .host_info.fqdn' \
  ./stats/machines/*/system_info.json | wc -l

# Find all VMs
jq -r 'select(.hypervisor.is_virtual == true) | .host_info.fqdn' \
  ./stats/machines/*/system_info.json

# Memory usage report
jq -r '"\(.host_info.fqdn): \(.memory.usage_percent)%"' \
  ./stats/machines/*/system_info.json

Example Playbooks

Basic Playbook

---
- name: Gather system information
  hosts: all
  become: true
  roles:
    - system_info

Advanced Playbook

---
- name: Gather detailed system information
  hosts: all
  become: true
  roles:
    - role: system_info
      vars:
        system_info_stats_base_dir: /var/lib/ansible/inventory
        system_info_json_indent: 4
        system_info_gather_gpu: true
        system_info_detect_hypervisor: true

Targeted Playbook

---
- name: Gather hypervisor information only
  hosts: hypervisors
  become: true
  tasks:
    - name: Include system_info role for hypervisor detection
      include_role:
        name: system_info
        tasks_from: detect_hypervisor
      tags: [hypervisor]

Troubleshooting

Check Role Execution

# Dry-run (check mode)
ansible-playbook site.yml -t system_info --check

# Verbose output
ansible-playbook site.yml -t system_info -v

# Very verbose (debug)
ansible-playbook site.yml -t system_info -vvv

# Single host debugging
ansible-playbook site.yml -l problematic-host -t system_info -vvv

Common Issues

Missing packages

# Install packages manually first
ansible-playbook site.yml -t system_info,install

# Check what would be installed
ansible all -m package_facts

Permission errors

# Ensure become is enabled
ansible-playbook site.yml -t system_info --become

# Check sudo access
ansible all -m ping --become

Statistics not saved

# Check if directory exists
ls -la ./stats/machines/

# Check disk space on control node
df -h .

# Verify write permissions
touch ./stats/machines/test && rm ./stats/machines/test

Validation

# Run only validation tasks
ansible-playbook site.yml -t system_info,validate

# Check specific host health
ansible-playbook site.yml -l server01 -t validate,health-check

# Verify JSON files
for f in ./stats/machines/*/system_info.json; do
  echo "Checking $f"
  jq empty "$f" && echo "OK" || echo "INVALID"
done

Performance Optimization

Parallel Execution

# Increase parallelism (default: 5)
ansible-playbook site.yml -t system_info -f 20

# Serial execution (one at a time)
ansible-playbook site.yml -t system_info -f 1

Skip Slow Tasks

# Skip installation if packages are pre-installed
ansible-playbook site.yml -t system_info --skip-tags install

# Skip network gathering (can be slow)
ansible-playbook site.yml -t system_info --skip-tags network

Integration Examples

Cron Job for Regular Collection

# Daily collection at 2 AM
0 2 * * * cd /opt/ansible && ansible-playbook site.yml -t system_info >> /var/log/ansible/system_info.log 2>&1

Generate HTML Report

# Convert JSON to HTML
for host in ./stats/machines/*; do
  hostname=$(basename "$host")
  jq -r 'to_entries | map("\(.key): \(.value)") | .[]' \
    "$host/system_info.json" > "$host/report.txt"
done

Compare Statistics

# Compare CPU across hosts
jq -r '"\(.host_info.fqdn),\(.cpu.model),\(.cpu.count.vcpus)"' \
  ./stats/machines/*/system_info.json | column -t -s,

# Compare memory across hosts
jq -r '"\(.host_info.fqdn),\(.memory.total_mb) MB,\(.memory.usage_percent)%"' \
  ./stats/machines/*/system_info.json | column -t -s,

Security Checkpoints

• ✓ Role runs with become: true for hardware access
• ✓ No credentials or secrets are collected
• ✓ Statistics files contain infrastructure details - protect appropriately
• ✓ Sensitive data (serial numbers, UUIDs) included - review before sharing
• ✓ Files stored on control node only - not on managed hosts

Quick Reference Commands

# Full scan
ansible-playbook site.yml -t system_info

# CPU + Memory only
ansible-playbook site.yml -t system_info,cpu,memory

# Validate all hosts
ansible-playbook site.yml -t system_info,validate

# Export only (no gathering)
ansible-playbook site.yml -t system_info,export

# Single host, verbose
ansible-playbook site.yml -l hostname -t system_info -v

# View latest stats
cat ./stats/machines/$(hostname -f)/summary.txt

Ansible Ad-Hoc Alternatives

# Quick CPU check
ansible all -m shell -a "lscpu | grep 'Model name'"

# Quick memory check
ansible all -m shell -a "free -h"

# Quick disk check
ansible all -m shell -a "df -h"

# Check virtualization
ansible all -m shell -a "systemd-detect-virt"

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Role: system_info v1.0.0 Updated: 2025-01-11 Documentation: See roles/system_info/README.md