s4k-admin-toolbox/tools/linux/docker-ce/network-manager

🐳 Docker Network Manager

A lightweight, production-ready Bash utility to manage external Docker bridge networks with automatic IPAM (IP Address Management). It ensures your network configurations are persistent, documented, and free from subnet overlaps.

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🚀 Key Features

• Smart Subnet Allocation: Automatically finds the next available /24 block within your specified range (e.g., 172.30.x.x).
• Infrastructure as Code (Lite): Keep your network names in a simple text file; the script handles the rest.
• Safe Operations:
  • Interactive confirmation for bulk deletions.
  • ShellCheck-validated code (Strict Mode: set -euo pipefail).
  • Non-interactive mode support (via FORCE=true).
• Status Dashboard: Instant overview of which tracked networks are ONLINE or OFFLINE.

🛠 Installation & Setup

1. Clone the repo (or add the code to your admin toolbox).
2. Create the config file:

cp docker-network-manager.conf.example docker-network-manager.conf
#OR
cat <<EOF > docker-network-manager.conf
NET_FILE="./dnm-networks.txt"
LOG_FILE="./dnm-networks.log"
BASE_NET="172.30"
START_OCTET=0
END_OCTET=255
EOF

3. Make script executable:

chmod +x docker-network-manager.sh

📖 Usage Examples

1. Check current status

   ./docker-network-manager.sh info
   

   Example:
   
2. Provision networks
   • From file: Add network names to dnm-networks.txt and run:

     ./docker-network-manager.sh create
     

   • Single network:

     ./docker-network-manager.sh create br-project-alpha
     

3. Decommission networks
   • Remove and cleanup:

     ./docker-network-manager.sh delete br-project-alpha
     

   • Purge all (from file):*

     ./docker-network-manager.sh delete
     

⚠️ IMPORTANT

Interface Name Limit: Linux has a 15-character limit for network interface names. Ensure your Docker network names stay within this limit to maintain consistent bridge naming.

🧩 Native OS Integration

Unlike standard Docker networks that create cryptic interface names (e.g., br-837d9f...), this manager assigns the actual network name to the Linux bridge interface.

This allows you to:

• Monitor traffic per-network using standard tools (tcpdump -i br-test1).
• Create persistent firewall rules (IPTables/NFTables) targeting specific bridges.
• Easily identify networks in ip addr or ifconfig output.
  Example:
  

📊 Summary Table of Commands

Command	Short	Argument	Description
create	c	[name]	Provisions network(s) and updates config file.
delete	d	[name]	Removes network(s) from Docker and config file.
info	i	-	Displays dashboard with IP ranges and statuses.

⚙️ Configuration Variables

Variable	Default	Description
BASE_NET	172.30	The first two octets of your managed pool.
START_OCTET	0	Starting range for the 3rd octet.
END_OCTET	255	Ending range for the 3rd octet.
NET_FILE	./dnm-networks.txt	File where network names are stored.

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⚖️ License

MIT LICENSE. Free to use and modify.