- What is Ansible?
- Ansible allows you to achieve "Simple IT Automation". You describe the desired state of your machines, and Ansible manipulates them to achieve this state. The file in which you describe the desired state is called Playbook, which is written in YAML.
- Control Node: the machine where Ansible is installed, responsible for running the provisioning on the servers you are managing.
- Inventory: an
INIfile that contains information about the servers you are managing. - Playbook: a
YAMLfile containing a series of procedures that should be automated. - Task: a block that defines a single procedure to be executed, e.g.: install a package.
- Module: a module typically abstracts a system task, like dealing with packages or creating and changing files. Ansible has a multitude of built-in modules, but you can also create custom ones.
- Role: a set of related playbooks, templates and other files, organized in a pre-defined way to facilitate reuse and sharing.
- Play: a provisioning executed from start to finish is called a play.
- Facts: global variables containing information about the system, like network interfaces or operating system.
- Handlers: used to trigger service status changes, like restarting or reloading a service.
- A basic Ansible command or playbook:
- selects machines to execute against from inventory
- connects to those machines (or network devices, or other managed nodes), usually over SSH
- copies one or more modules to the remote machines and starts execution there
- Working with Modules
- Ansible ships with a number of modules (called the ‘module library’) that can be executed directly on remote hosts or through Playbooks.
- Users can also write their own modules. These modules can control system resources, like services, packages, or files (anything really), or handle executing system commands.