Modernize Nagios, Salt, and Squid installation scripts

[errnair]

Description

Modernized the remaining four installation scripts (Nagios, Salt Master, Salt Minion, Squid) with multi-OS support, modern repositories, and comprehensive configurations.

Changes

install_nagios.sh

• Multi-OS support: RHEL/Rocky/AlmaLinux/Ubuntu/Debian
• Updated versions: Nagios Core 4.5.0, Plugins 2.4.6, NRPE 4.1.0
• Builds from source with proper compilation flags
• Secure password input for web admin (no command-line passwords)
• SELinux configuration with proper contexts
• Auto-generates example configuration files
• Firewall support (firewalld and ufw)
• Comprehensive testing and validation

install_salt.sh

• Multi-OS support with updated SaltProject repositories
• Modern repo.saltproject.io URLs (Python 3)
• Version selection: latest or specific version
• Optional components: minion, ssh, cloud
• Auto-generates master configuration in /etc/salt/master.d/
• Creates example Salt states (top.sls, common.sls)
• Firewall configuration for Salt ports 4505 and 4506
• Minion key acceptance and connectivity testing

install_salt_minion.sh

• Multi-OS support with SaltProject repos
• Requires master IP/hostname as parameter
• Version selection support
• Custom minion ID configuration
• Proper minion.d configuration structure
• Validates master address (IP, hostname, or FQDN)
• Connection testing with troubleshooting guide
• Comprehensive setup instructions for master

install_squid.sh

• Multi-OS support: RHEL/Rocky/AlmaLinux/Ubuntu/Debian
• Three proxy modes: forward, transparent, reverse
• Configurable port and cache size
• Network ACL support (CIDR notation)
• Website blocking capability (/etc/squid/blocked_sites)
• Configuration backup with timestamps
• Cache directory initialization
• Firewall configuration

Usage Examples

# Nagios
./install_nagios.sh

# Salt Master
./install_salt.sh
SALT_VERSION=3006 ./install_salt.sh

# Salt Minion
./install_salt_minion.sh 192.168.1.100
MINION_ID=webserver01 ./install_salt_minion.sh salt.master

# Squid (forward proxy)
./install_squid.sh
ALLOWED_NETWORK=192.168.1.0/24 ./install_squid.sh

# Squid (transparent proxy)
SQUID_MODE=transparent ./install_squid.sh

# Squid (reverse proxy)
SQUID_MODE=reverse BACKEND_HOST=10.0.0.50 BACKEND_PORT=8080 ./install_squid.sh

Tests

All scripts passed testing:

• Bash syntax validation: OK
• Library integration: verified
• Common library functions properly utilized
• Error handling with set -euo pipefail: verified