* Ansible seamlessly unites workflow orchestration with configuration management, provisioning, and application deployment in one easy-to-use and deploy platform. * Regardless of where you start with Ansible, you’ll find our simple, powerful and agentless automation platform has the capabilities to solve your most challenging problems. * PROVISIONING - Your apps have to live somewhere. If you’re PXE booting and kickstarting bare-metal servers or VMs, or creating virtual or cloud instances from templates, Ansible and Ansible Tower help streamline the process. * CONFIGURATION MANAGEMENT - Centralizing configuration file management and deployment is a common use case for Ansible, and it’s how many power users are first introduced to the Ansible automation platform. * APPLICATION DEPLOYMENT - When you define your application with Ansible, and manage the deployment with Tower, teams are able to effectively manage the entire application lifecycle from development to production. * CONTINUOUS DELIVERY - Creating a CI/CD pipeline requires buy-in from numerous teams. You can’t do it without a simple automation platform that everyone in your organization can use. Ansible Playbooks keep your applications properly deployed (and managed) throughout their entire lifecycle. * SECURITY & COMPLIANCE - When you define your security policy in Ansible, scanning and remediation of site-wide security policy can be integrated into other automated processes and instead of being an afterthought, it’ll be integral in everything that is deployed. * ORCHESTRATION - Configurations alone don’t define your environment. You need to define how multiple configurations interact and ensure the disparate pieces can be managed as a whole. Out of complexity and chaos, Ansible brings order. * COMMUNITY-POWERED - Ansible is the most popular open source automation tool on GitHub today. With over 2,000 contributors submitting new modules all the time, rest assured that what you are automating is covered in Ansible already, or will be very soon. * ENTERPRISE READY - Ansible Tower by Red Hat builds on the underlying Ansible automation engine by adding control, security, and delegation capabilities. With Ansible and Tower, your team can automate –and your business can innovate.

* Declarative system configuration model In NixOS, the entire operating system — the kernel, applications, system packages, configuration files, and so on — is built by the Nix package manager from a description in a purely functional build language. The fact that it’s purely functional essentially means that building a new configuration cannot overwrite previous configurations. Most of the other features follow from this.- Reliable upgrades Another advantage of purely functional package management is that nixos-rebuild switch will always produce the same result, regardless of what packages or configuration files you already had on your system. Thus, upgrading a system is as reliable as reinstalling from scratch. * Atomic upgrades - NixOS has a transactional approach to configuration management: configuration changes such as upgrades are atomic. This means that if the upgrade to a new configuration is interrupted — say, the power fails half-way through — the system will still be in a consistent state: it will either boot in the old or the new configuration. In most other systems, you’ll end up in an inconsistent state, and your machine may not even boot anymore. * Rollbacks - Because the files of a new configuration don’t overwrite old ones, you can (atomically) roll back to a previous configuration. For instance, if after a nixos-rebuild switch you discover that you don’t like the new configuration, you can just go back. * Reproducible system configurations NixOS’ declarative configuration model makes it easy to reproduce a system configuration on another machine (for instance, to test a change in a test environment before doing it on the production server). You just copy the configuration.nix file to the target NixOS machine and run nixos-rebuild switch. This will give you the same configuration (kernel, applications, system services, and so on) except for ‘mutable state’ (such as the stuff that lives in /var). * Safe to test changes - NixOS makes it safe to test potentially dangerous changes to the system, because you can always roll back. (Unless you screw up the boot loader, that is…) For instance, whether the change is as simple as enabling a system service, or as large as rebuilding the entire system with a new version of Glibc.