Here are some of the most popular and widely used Configuration Management tools: Ansible: This is a powerful, agentless automation engine. It uses a simple, human-readable language (YAML) to define automation tasks in "playbooks." Ansible excels at configuration management, application deployment, task automation, and orchestration. Its agentless nature (it connects via SSH or WinRM) makes it relatively easy to set up and manage. Chef: Chef uses a Ruby-based Domain Specific Language (DSL) to define infrastructure as code. "Cookbooks" contain recipes that describe the desired state of systems. Chef typically uses an agent ("chef-client") installed on the managed nodes that communicates with a central Chef server. It's known for its strong focus on infrastructure automation and compliance. Puppet: Similar to Chef, Puppet also uses a declarative language to define the desired state of infrastructure. "Manifests" describe configurations, and an agent ("Puppet agent") on managed nodes communicates with a central "Puppet master." Puppet is a mature and widely adopted tool, particularly in larger and more complex environments, known for its robust reporting and enforcement capabilities. SaltStack (Salt): Salt is a Python-based configuration management and remote execution tool. It's known for its speed and scalability, leveraging a master-minion architecture with a fast communication bus. Salt is often praised for its powerful remote execution capabilities alongside its configuration management features. Terraform: While often categorized as an Infrastructure-as-Code (IaC) tool, Terraform plays a crucial role in configuration management, especially at the infrastructure level. It allows you to define and provision infrastructure (servers, networks, databases, etc.) across various cloud providers and on-premise environments using a declarative configuration language (HCL). Terraform focuses on managing the lifecycle of infrastructure resources.