Introduction: Before Ansible There Was Bash

Before configuration management tools like Ansible, Puppet, or CFEngine became mainstream, system administrators relied on simpler tools. Bash, despite its age, offers surprising capabilities that many modern administrators overlook. This article demonstrates how to create an Ansible-like execution framework using pure Bash, with features like:

• Idempotent execution
• Parallel processing
• Remote script injection
• Result aggregation
• Jump host support

The Power of Simple Solutions

The provided script (script_remote.sh) demonstrates how to execute commands across multiple servers efficiently. Key advantages include:

1. Zero-Copy Execution: Scripts are injected directly into SSH sessions
2. Resource Efficiency: Single SSH connection per host
3. Immediate Feedback: Results are returned in real-time
4. Parallel Processing: Configurable number of simultaneous connections

Quick Start Example

# Clone the repository
git clone https://github.com/rrafal1337/bash.git

# Create a simple test script
echo "uname -a" > somescript.sh

# Execute on multiple hosts
./script_remote.sh --hosts '{falcon,stork}' --script somescript.sh 

Example output:

falcon, Linux falcon 6.16.8-200.fc42.x86_64 #1 SMP PREEMPT_DYNAMIC Fri Sep 19 17:47:18 UTC 2025 x86_64 GNU/Linux 
stork, Linux stork 6.12.34+rpt-rpi-v7 #1 SMP Raspbian 1:6.12.34-1+rpt1~bookworm (2025-06-26) armv7l GNU/Linux 

Scaling to Hundreds of Hosts

One of Bash's powerful features is pattern expansion. Consider this example:

echo serv{100..200}{a,b,c}

This instantly generates 303 hostnames (101 numbers × 3 letters). Combined with parallel execution, we can efficiently manage large server farms:

# Execute on 303 hosts using 64 parallel threads
./script_remote.sh --hosts 'serv{100..200}{a,b,c}' --processes 64 --script update.sh

Performance Considerations

The script uses xargs for parallel execution, maintaining a constant number of active threads. When one host completes, another takes its place, ensuring optimal resource utilization.

Advanced Features

• Jump Host Support

./script_remote.sh --hosts 'internal-host' --script check.sh --jumpbox gateway.example.com

• Configurable Parallelism

./script_remote.sh --hosts 'webserv{1..100}' --processes 32 --script deploy.sh

• Result Aggregation

./script_remote.sh --hosts 'dbserv{1..50}' --script status.sh > report.txt

Conclusion

While modern configuration management tools offer many features, sometimes a simple Bash script can provide similar functionality with less overhead. This approach is particularly useful for:

• Quick deployments
• Performance-critical operations
• Systems with minimal dependencies
• Learning automation fundamentals