Configuration Management Tools

Configuration management is the practice of defining and maintaining product attributes throughout its life. Traditionally used for servers and applications, these tools now enhance network operations. Benefits include automation, no need for programming skills, software development practices, and tools like Puppet, Ansible, and Chef. 

Manual network changes can be automated efficiently with these tools, which enforce system, interface, and routing configurations. Commonly known as DevOps tools, they offer high automation levels, enhancing predictability. Typically, a central server defines the desired system state, which is enforced across devices.

Agent vs Agentless Tools 

The two models of automated configuration management represent different philosophies. The first is the intent-based model, where a central server defines the desired system state, enforced by agents on system elements. This model is pull-based and requires agent installation on network devices. 

The second model is an evolution of CLI and SSH techniques, emphasizing reusable command sets and scalability. It's agentless, employing remote shell access and a push model to deliver scripts for configuration. The agent-based approach, as seen in Puppet and Chef, has agents monitoring and enforcing configuration, while agentless methods, like Ansible, use playbooks and modules to provision target elements. 

Consider that both approaches offer unified configuration management, enhancing efficiency and agility. Choose the most suitable tool based on your requirements, network setup, personal preferences, and goals.