Ansible Host Limiter Skill

Ansible Host Limiter Skill

Purpose

This skill enforces a critical safety practice for the home-server infrastructure: always limit ansible commands to specific hosts to prevent accidental execution on unintended targets like the raspberry-printer.

Target Hosts

Primary Target (Default)

• ndelucca-server: The main home server running Fedora 43

Hosts to Avoid (Unless Explicitly Requested)

• ndelucca-raspberry-printer: Raspberry Pi running Debian (not Fedora)
• Any other hosts in the inventory

Mandatory Rules

Rule 1: Always Use -l Flag

Every ansible-playbook and ansible command MUST include the -l (limit) flag.

Correct:

ansible-playbook playbooks/​jellyfin.yml -l ndelucca-server
ansible-playbook playbooks/​site.yml -l ndelucca-server
ansible ndelucca-server -m ping

Incorrect (NEVER DO THIS):

ansible-playbook playbooks/​jellyfin.yml
ansible-playbook playbooks/​site.yml
ansible all -m ping

Rule 2: Default to ndelucca-server

Unless the user explicitly requests a different target, always default to -l ndelucca-server.

Rule 3: Confirm Before Multi-Host Execution

If the user asks to run commands on multiple hosts or "all" hosts, ask for explicit confirmation before proceeding.

Implementation Guidelines

When Running Playbooks

1. User says: "Run the jellyfin playbook" You execute:

   ansible-playbook playbooks/​jellyfin.yml -l ndelucca-server
   

2. User says: "Deploy nginx" You execute:

   ansible-playbook playbooks/​site.yml --tags nginx -l ndelucca-server
   

3. User says: "Run the site playbook" You execute:

   ansible-playbook playbooks/​site.yml -l ndelucca-server
   

When Running Ad-Hoc Commands

1. User says: "Restart nginx" You execute:

   ansible ndelucca-server -m ansible.builtin.systemd -a "name=nginx state=restarted" --become
   

2. User says: "Check disk space" You execute:

   ansible ndelucca-server -m shell -a "df -h"
   

When User Requests Multi-Host Execution

User says: "Run this on all servers"

You respond: "This command would affect multiple hosts including ndelucca-raspberry-printer. Are you sure you want to run it on all hosts, or should I limit it to ndelucca-server only?"

Wait for user confirmation before proceeding.

Safety Checklist

Before executing any ansible command, verify:

• The -l flag is present
• The target is ndelucca-server (or user explicitly requested otherwise)
• The command is appropriate for the targeted host
• The playbook/​role supports the target OS (ndelucca-server runs Fedora 43)

Common Commands with Correct Syntax

# Run site playbook (all roles)
ansible-playbook playbooks/​site.yml -l ndelucca-server

# Run specific playbook
ansible-playbook playbooks/​jellyfin.yml -l ndelucca-server
ansible-playbook playbooks/​nginx.yml -l ndelucca-server

# Run with tags
ansible-playbook playbooks/​site.yml --tags nginx -l ndelucca-server

# Ad-hoc command to restart service
ansible ndelucca-server -m ansible.builtin.systemd -a "name=jellyfin state=restarted" --become

# Ad-hoc command to check service status
ansible ndelucca-server -m ansible.builtin.systemd -a "name=nginx" --become

# Syntax check
ansible-playbook playbooks/​site.yml --syntax-check -l ndelucca-server

Error Prevention

Common Mistakes to Avoid

1. Running without -l flag: This will execute on ALL hosts in inventory
2. Using all as host pattern: Affects all hosts including raspberry-printer
3. Forgetting --become: Some tasks require sudo privileges

What to Do If User Asks to Run Without Limiting

Never run ansible commands without the -l flag unless the user:

1. Explicitly says "run on all hosts" or "run on raspberry-printer"
2. Confirms they understand it will affect multiple hosts
3. You've warned them about the consequences

Examples of Correct Behavior

Example 1: Implicit Target

User: "run the playbook first, make sure nothing brakes"
You: Execute: ansible-playbook playbooks/​site.yml -l ndelucca-server

Example 2: Service Management

User: "restart jellyfin"
You: Execute: ansible ndelucca-server -m ansible.builtin.systemd -a "name=jellyfin state=restarted" --become

Example 3: Configuration Update

User: "deploy the nginx changes"
You: Execute: ansible-playbook playbooks/​site.yml --tags nginx -l ndelucca-server

Notes

• The raspberry-printer runs Debian, not Fedora, so Fedora-specific playbooks will fail on it
• Always working directory: /​home/​ndelucca/​environment/​home-server
• Inventory files are in: inventory/​hosts.yml and playbooks/​hosts.yml
• Most playbooks are in: playbooks/ directory

Summary

Golden Rule: Every ansible-playbook and ansible command MUST include -l ndelucca-server unless explicitly instructed otherwise by the user.