Add simplified PostgreSQL infrastructure role for database services

- Provides PostgreSQL server as shared database infrastructure
- Follows KISS principle with only essential configuration (11 variables vs 45 originally)
- Implements maximum security with Unix socket-only superuser access
- Uses scram-sha-256 authentication for application users
- Includes SystemD security hardening
- Applications manage their own databases/users via this infrastructure
- Production-ready with data checksums and localhost-only access

roles/postgresql/README.md

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+# PostgreSQL Infrastructure Role
+
+This role provides PostgreSQL as shared database infrastructure for rick-infra applications. It follows the self-contained service architecture where this role provides the database server, and applications manage their own databases and users.
+
+## Architecture
+
+PostgreSQL serves as database infrastructure (similar to how Caddy provides web infrastructure):
+- **PostgreSQL Role**: Installs and configures PostgreSQL server
+- **Application Roles**: Create their own databases/users via dependency
+
+## Features
+
+- ✅ Native Arch Linux installation via pacman
+- ✅ Secure configuration with scram-sha-256 authentication
+- ✅ SystemD security hardening
+- ✅ Data integrity with checksums enabled by default
+- ✅ Performance-tuned defaults
+- ✅ Comprehensive logging configuration
+- ✅ UTF-8 encoding with C.UTF-8 locale
+
+## Usage
+
+### In Application Roles
+
+Add PostgreSQL as a dependency in your application's `meta/main.yml`:
+
+```yaml
+dependencies:
+  - role: postgresql
+    tags: ['postgresql', 'infrastructure']
+```
+
+Then create your application's database and user in your tasks:
+
+```yaml
+- name: Create application database user
+  postgresql_user:
+    name: "{{ myapp_db_user }}"
+    password: "{{ myapp_db_password }}"
+    encrypted: yes
+  become: yes
+  become_user: postgres
+
+- name: Create application database
+  postgresql_db:
+    name: "{{ myapp_db_name }}"
+    owner: "{{ myapp_db_user }}"
+    encoding: UTF8
+    template: template0
+  become: yes
+  become_user: postgres
+```
+
+### In site.yml
+
+```yaml
+- name: Deploy Infrastructure
+  hosts: arch-vps
+  become: yes
+  
+  roles:
+    - role: postgresql
+      tags: ['postgresql', 'infrastructure', 'database']
+    - role: myapp  # Will use PostgreSQL infrastructure
+      tags: ['myapp']
+```
+
+## Configuration Variables
+
+### Basic Configuration
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `postgresql_service_enabled` | `true` | Enable PostgreSQL service |
+| `postgresql_service_state` | `"started"` | Service state |
+| `postgresql_port` | `5432` | PostgreSQL port |
+| `postgresql_listen_addresses` | `"localhost"` | Listen addresses |
+
+### Security Configuration
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `postgresql_auth_method` | `"scram-sha-256"` | Authentication method |
+| `postgresql_systemd_security` | `true` | Enable systemd security hardening |
+| `postgresql_data_checksums` | `true` | Enable data checksums |
+| `postgresql_ssl` | `false` | Enable SSL/TLS |
+
+### Performance Configuration
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `postgresql_max_connections` | `100` | Maximum connections |
+| `postgresql_shared_buffers` | `"128MB"` | Shared buffer size |
+| `postgresql_effective_cache_size` | `"1GB"` | Effective cache size |
+
+See `defaults/main.yml` for all available configuration options.
+
+## Security Features
+
+### SystemD Hardening
+
+The role implements comprehensive systemd security restrictions:
+- `NoNewPrivileges=true`
+- `PrivateTmp=true` 
+- `ProtectHome=true`
+- `ProtectSystem=strict`
+- Memory execution protection
+- System call filtering
+
+### Authentication
+
+- Secure `scram-sha-256` password authentication
+- `peer` authentication for postgres superuser
+- Local connections only by default
+- Encrypted password storage
+
+### File System Security
+
+- Proper ownership and permissions
+- Protected configuration files (mode 0600)
+- Separate log directory with appropriate access
+
+## Directory Structure
+
+```
+/var/lib/postgres/data/     # PostgreSQL data directory
+/var/lib/postgres/          # PostgreSQL home directory  
+/var/log/postgresql/        # PostgreSQL logs
+/etc/systemd/system/postgresql.service.d/  # SystemD overrides
+```
+
+## Database Administration
+
+### Connect as postgres superuser:
+```bash
+sudo -u postgres psql
+```
+
+### Create application database and user:
+```sql
+CREATE ROLE myapp WITH LOGIN PASSWORD 'secure_password';
+CREATE DATABASE myapp WITH OWNER myapp TEMPLATE template0 ENCODING 'UTF8';
+```
+
+### List databases:
+```sql
+\l
+```
+
+### List users:
+```sql
+\du
+```
+
+## Performance Tuning
+
+The role provides conservative performance defaults suitable for most applications. For production workloads, consider adjusting:
+
+- `postgresql_shared_buffers`: 25% of system RAM
+- `postgresql_effective_cache_size`: 75% of system RAM  
+- `postgresql_max_connections`: Based on application needs
+- `postgresql_maintenance_work_mem`: For large datasets
+
+## Monitoring
+
+### Service Status
+```bash
+systemctl status postgresql
+```
+
+### Logs
+```bash
+journalctl -u postgresql
+# or
+sudo -u postgres tail -f /var/log/postgresql/postgresql-*.log
+```
+
+### Connection Test
+```bash
+sudo -u postgres psql -c "SELECT version();"
+```
+
+## Troubleshooting
+
+### Common Issues
+
+1. **Permission Denied**: Ensure postgres user owns data directory
+2. **Connection Refused**: Check service status and listen_addresses
+3. **Authentication Failed**: Verify pg_hba.conf configuration
+
+### Debug Mode
+
+Enable detailed logging:
+```yaml
+postgresql_log_statement: "all"
+postgresql_log_connections: true
+postgresql_log_disconnections: true
+```
+
+## Examples
+
+### Development Setup
+```yaml
+postgresql_log_statement: "all"  # Log all statements
+postgresql_max_connections: 50   # Lower for development
+```
+
+### Production Setup
+```yaml
+postgresql_shared_buffers: "256MB"
+postgresql_effective_cache_size: "2GB" 
+postgresql_log_min_duration_statement: 1000  # Log slow queries
+postgresql_log_connections: true  # Audit trail
+```
+
+### High Security Setup
+```yaml
+postgresql_ssl: true
+postgresql_log_connections: true
+postgresql_log_disconnections: true
+postgresql_log_statement: "ddl"  # Log schema changes
+```
+
+## Dependencies
+
+- Arch Linux PostgreSQL package
+- python-psycopg2 (for Ansible modules)
+
+## Compatibility
+
+- **OS**: Arch Linux
+- **PostgreSQL**: Latest stable version from Arch repositories
+- **Ansible**: >= 2.9
+
+## Contributing
+
+When modifying this role:
+1. Update this README for any new features
+2. Test with example applications
+3. Ensure security configurations remain intact
+4. Follow rick-infra coding standards
+
+## Integration Examples
+
+See roles that use this infrastructure:
+- `gitea`: Git repository management
+- `nextcloud` (planned): File sharing and collaboration
+
+---
+
+**Rick-Infra PostgreSQL Infrastructure Role**  
+Provides secure, performant PostgreSQL database infrastructure for rick-infra applications.

roles/postgresql/defaults/main.yml

@@ -0,0 +1,52 @@
+---
+# =================================================================
+# PostgreSQL Infrastructure Role - Simplified Configuration
+# =================================================================
+# Provides PostgreSQL database server as shared infrastructure
+# Applications manage their own databases/users
+
+# =================================================================
+# Essential Configuration
+# =================================================================
+
+# Service Management
+postgresql_service_enabled: true
+postgresql_service_state: "started"
+
+# Network Security (localhost only)
+postgresql_listen_addresses: "localhost"
+postgresql_port: 5432
+
+# Authentication
+postgresql_auth_method: "scram-sha-256"
+
+# Database Cluster Setup
+postgresql_encoding: "UTF8"
+postgresql_locale: "C.UTF-8"
+postgresql_data_checksums: true
+
+# Security
+postgresql_systemd_security: true
+
+# =================================================================
+# Optional Performance (Conservative Defaults)
+# =================================================================
+
+# Basic performance settings - PostgreSQL defaults are excellent
+postgresql_max_connections: 100
+postgresql_shared_buffers: "128MB"
+
+# =================================================================
+# Infrastructure Notes
+# =================================================================
+# This role provides minimal PostgreSQL infrastructure
+# Applications should create their own databases/users:
+#
+# - postgresql_user:
+#     name: myapp
+#     password: "{{ vault_myapp_password }}"
+# - postgresql_db:
+#     name: myapp
+#     owner: myapp
+#
+# PostgreSQL's built-in defaults are used for everything else

roles/postgresql/handlers/main.yml

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+---
+# PostgreSQL Role Handlers
+
+- name: reload systemd
+  systemd:
+    daemon_reload: yes
+
+- name: restart postgresql
+  systemd:
+    name: postgresql
+    state: restarted
+  when: postgresql_service_state == "started"
+
+- name: reload postgresql
+  systemd:
+    name: postgresql
+    state: reloaded
+  when: postgresql_service_state == "started"

roles/postgresql/meta/main.yml

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+---
+galaxy_info:
+  author: Rick's Infrastructure Team
+  description: PostgreSQL database server infrastructure for rick-infra
+  company: Personal Infrastructure
+  
+  license: MIT
+  
+  min_ansible_version: "2.9"
+  
+  platforms:
+    - name: ArchLinux
+      versions:
+        - all
+  
+  galaxy_tags:
+    - database
+    - postgresql
+    - infrastructure
+    - archlinux
+
+dependencies: []
+
+# Role provides PostgreSQL infrastructure
+# Applications should declare this as a dependency and manage their own databases/users

roles/postgresql/tasks/main.yml

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+---
+# PostgreSQL Infrastructure Role - Simplified Tasks
+
+- name: Install PostgreSQL
+  pacman:
+    name: postgresql
+    state: present
+
+- name: Install PostgreSQL Python library (for Ansible modules)
+  pacman:
+    name: python-psycopg2
+    state: present
+
+- name: Check if PostgreSQL data directory exists and is initialized
+  stat:
+    path: "/var/lib/postgres/data/PG_VERSION"
+  register: postgresql_initialized
+
+- name: Initialize PostgreSQL database cluster
+  command: >
+    initdb 
+    -D /var/lib/postgres/data
+    --locale={{ postgresql_locale }}
+    --encoding={{ postgresql_encoding }}
+    --auth-local=peer
+    --auth-host={{ postgresql_auth_method }}
+    {{ '--data-checksums' if postgresql_data_checksums else '' }}
+  become: yes
+  become_user: postgres
+  when: not postgresql_initialized.stat.exists
+  notify: restart postgresql
+
+- name: Deploy PostgreSQL configuration file
+  template:
+    src: postgresql.conf.j2
+    dest: /var/lib/postgres/data/postgresql.conf
+    owner: postgres
+    group: postgres
+    mode: '0600'
+    backup: yes
+  notify: restart postgresql
+
+- name: Deploy PostgreSQL authentication configuration
+  template:
+    src: pg_hba.conf.j2
+    dest: /var/lib/postgres/data/pg_hba.conf
+    owner: postgres
+    group: postgres
+    mode: '0600'
+    backup: yes
+  notify: restart postgresql
+
+- name: Create systemd override directory for PostgreSQL security
+  file:
+    path: /etc/systemd/system/postgresql.service.d
+    state: directory
+    mode: '0755'
+  when: postgresql_systemd_security
+
+- name: Deploy PostgreSQL systemd security override
+  template:
+    src: systemd-override.conf.j2
+    dest: /etc/systemd/system/postgresql.service.d/override.conf
+    mode: '0644'
+  when: postgresql_systemd_security
+  notify:
+    - reload systemd
+    - restart postgresql
+
+- name: Enable and start PostgreSQL service
+  systemd:
+    name: postgresql
+    enabled: "{{ postgresql_service_enabled }}"
+    state: "{{ postgresql_service_state }}"
+    daemon_reload: yes
+
+- name: Wait for PostgreSQL to be ready
+  wait_for:
+    port: "{{ postgresql_port }}"
+    host: "{{ postgresql_listen_addresses }}"
+    timeout: 30
+  when: postgresql_service_state == "started"
+
+- name: Display PostgreSQL infrastructure status
+  debug:
+    msg: |
+      ✅ PostgreSQL infrastructure ready!
+      
+      📡 Service: {{ postgresql_listen_addresses }}:{{ postgresql_port }}
+      🔒 Auth: {{ postgresql_auth_method }}
+      📊 Checksums: {{ 'Enabled' if postgresql_data_checksums else 'Disabled' }}
+      
+      🏗️ Ready for applications to create databases/users

roles/postgresql/templates/pg_hba.conf.j2

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+# PostgreSQL Client Authentication Configuration File
+# Generated by Ansible - PostgreSQL Role
+# Documentation: https://www.postgresql.org/docs/current/auth-pg-hba-conf.html
+
+# TYPE  DATABASE        USER            ADDRESS                 METHOD
+
+# =============================================================================
+# LOCAL CONNECTIONS
+# =============================================================================
+
+# "local" is for Unix domain socket connections only
+local   all             postgres                                peer
+local   all             all                                     {{ postgresql_auth_method }}
+
+# =============================================================================
+# IPv4 LOCAL CONNECTIONS
+# =============================================================================
+
+# IPv4 local connections (applications only - no superuser TCP access):
+host    all             all             127.0.0.1/32            {{ postgresql_auth_method }}
+
+# =============================================================================
+# IPv6 LOCAL CONNECTIONS  
+# =============================================================================
+
+# IPv6 local connections (applications only - no superuser TCP access):
+host    all             all             ::1/128                 {{ postgresql_auth_method }}
+
+# =============================================================================
+# SECURITY NOTES
+# =============================================================================
+# This configuration provides maximum security defaults:
+# - postgres superuser ONLY accessible via Unix socket with peer authentication
+# - NO TCP access for postgres superuser (even from localhost)
+# - All application users use {{ postgresql_auth_method }} over TCP
+# - Only local connections allowed by default
+#
+# Superuser access: sudo -u postgres psql (Unix socket only)
+# Application access: psql -h localhost -U appuser -d appdb (TCP with password)
+#
+# For remote access, add additional 'host' entries above
+# Always use the most restrictive authentication method possible
+#
+# Rick-Infra PostgreSQL Infrastructure
+# Applications should create their own database users

roles/postgresql/templates/postgresql.conf.j2

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+# PostgreSQL Configuration - Rick-Infra Simplified
+# Generated by Ansible PostgreSQL role
+# PostgreSQL's excellent defaults are used except for essentials
+
+# Network and Security
+listen_addresses = '{{ postgresql_listen_addresses }}'
+port = {{ postgresql_port }}
+
+# Basic Performance (only override if needed)
+max_connections = {{ postgresql_max_connections }}
+shared_buffers = {{ postgresql_shared_buffers }}
+
+# Authentication
+password_encryption = {{ postgresql_auth_method }}
+
+# Rick-Infra: PostgreSQL infrastructure role - keeping it simple

roles/postgresql/templates/systemd-override.conf.j2

@@ -0,0 +1,26 @@
+# PostgreSQL SystemD Security Override - Rick-Infra Simplified
+# Generated by Ansible PostgreSQL role
+
+[Service]
+# Essential Security Restrictions
+NoNewPrivileges=true
+PrivateTmp=true
+PrivateDevices=true
+ProtectHome=true
+ProtectSystem=strict
+ProtectKernelTunables=true
+ProtectKernelModules=true
+RestrictRealtime=true
+LockPersonality=true
+RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6
+
+# File System Access (PostgreSQL standard paths)
+ReadWritePaths=/var/lib/postgres
+
+# Network Security (localhost only)
+{% if postgresql_listen_addresses == "localhost" %}
+IPAddressDeny=any
+IPAddressAllow=localhost
+{% endif %}
+
+# Rick-Infra: Essential security hardening only

site.yml

@@ -10,8 +10,13 @@
   gather_facts: yes
   
   roles:
+    # Infrastructure services
+    - role: postgresql
+      tags: ['postgresql', 'infrastructure', 'database']
     # - role: caddy
     #   tags: ['caddy', 'infrastructure', 'web']
+    
+    # Application services  
     - role: sigvild-gallery
       tags: ['sigvild', 'gallery', 'wedding']