Glossary
A
ad hoc command An Ansible command that uses a module to apply the desired state without making any change to the managed system.
anacron A helper system to Linux cron, which makes sure that a job is started periodically every hour, day, week, or month, without specifically defining when exactly it should run.
Ansible Tower A web-based platform that allows for management of Ansible environments from a browser.
ansible.cfg The configuration file that Ansible uses to get information about required settings. The parameters from ansible.cfg may be overwritten in playbooks.
AppStream The package collection in RHEL 8 that offers access to nonessential packages. Packages in AppStream are provided as yum modules, which allows for different versions of the packages to be offered.
array See List.
authorized_keys The name of the file that is created for each user in the .ssh directory in the user home directory and contains public keys that enable password-less login for remote users who have copied over their public key to this file after generating a public/private key pair using ssh-keygen.
automation language The format that is used to define the machine-readable code used to implement infrastructure as code.
AWX The open-source upstream project for Ansible Tower.
B
block A group of tasks that can be treated as one entity while working with conditionals.
C
check mode A mode in which Ansible shows what happens if a playbook is executed but doesn’t change anything. Running a playbook in check mode doesn’t always show everything that would be changed because the result of executing one task may depend on the result of another task.
CI/CD Continuous integration/continuous delivery; a way of easily developing software and updating software source code and making these new developments available as new versions to the end users using a CI/CD pipeline.
controller node The node in the Ansible configuration where all the Ansible management commands are issued.
current state The current configuration of a managed system.
CVS Concurrent version system, a system that makes it possible to manage different versions of code while it is developed. CVS is a way to implement version control systems.
D
declarative approach A way of working that uses configuration files (playbooks in the case of Ansible) instead of commands that declare the desired state and that are easy to roll out against the managed targets in an idempotent way.
desired state The state that is defined in Ansible playbooks and that needs to be implemented on Ansible-managed systems.
DevOps A contraction of the words developers and operators. It’s a new way of working in which developers integrate operator tasks in their work and operators integrate developer tasks in their work.
dictionary In Python, an unordered collection of items; also referred to as hashes. It is a collection of key-value pairs. In Python, a dictionary is defined as my_dict = { key1: ’car’, key2:’bike’ }. Because it is based on Python, Ansible enables users to use dictionaries as an alternative notation to arrays. Items in values in a dictionary do not start with a dash. Using dictionaries is one way; the alternative is to use a list. See also list, to compare differences.
E
EPEL repository The Extra Packages for Enterprise Linux, a repository that contains packages from the Fedora project for use on Red Hat Enterprise Linux or CentOS, but which have not officially been approved for these platforms.
F
failure condition The definition of what exactly is to be considered a failure when running Ansible playbooks.
fact A system property that is detected while starting a playbook.
filter A tool that can be used to perform an action on the result of a variable. For instance, filters can be used to change the variable type from string to integer.
fork A task that can be executed in parallel task execution.
G
Galaxy The Ansible community website, accessible at https://galaxy.ansible.com, where Ansible roles and collections are provided.
Git repository An online repository that developers can use to coordinate changes into software projects, including version control such that it is easy to roll back to the previous state of the software.
GPG GNU Privacy Guard; an open-source implementation of PGP, in which public/private keys can be used to enhance security. In repositories, the repository GPG private key is used to sign packages. Next, the repository client needs to import the GPG public key of that repository to verify the package signature before packages are installed.
H
handler A special type of task that runs only if triggered by another task.
hash (In key-value pairs) See dictionary.
hash (In encryption) An encoded representation of a string that was created with the purpose of securing the original string.
hashing algorithm A mathematical formula used to generate a hash.
I
idempotent A way of working in which Ansible ensures that running the same playbook multiple times will always result in the same code.
import An option that enables items to be statically imported before any task will run. Task files and plays can be imported.
include An option that enables items to be dynamically included depending on a conditional statement. Task files can be included.
infrastructure as code A way of working in which the entire infrastructure of an IT environment is defined as code (like Ansible playbooks) that can easily be deployed to implement a new desired state.
init system The system that is used on Linux to start essential system components after booting the system. Common init systems are BSD init (used on RHEL 5), Upstart (used on RHEL 6), and systemd (the default since RHEL 7).
inventory A list of managed hosts. It may be provided as a static file or as a script that dynamically discovers manageable hosts (dynamic inventory).
item An element in a list of variables.
J
Jinja2 A generic templating language for Python developers.
K
key-value In a YAML dictionary, the key is the specific item that is to be defined. An example of a key is “name.” The value is the specific value that is set to that name.
L
list In variable definition, a key that can have multiple items as its value; also referred to as an array. Each item in a list starts with a dash (-). Individual items in a list can be addressed, using the index number (starting at zero), as in {{ network_interfaces[1] }}. Compare to how key-value pairs can be specified in a dictionary.
local fact A fact that is defined as a local variable and is stored on the managed host.
look-up plug-in A plug-in that allows access to external data sources.
M–O
magic variable A reserved system variable that is stored as a default value and cannot be overwritten.
managed node The node that is managed by Ansible.
module The commands that are executed by using Ansible commands. Ansible modules provide the intelligence to Ansible.
P–Q
PAM In Linux, Pluggable Authentication Modules. An advanced framework that allows for enhancement of standard Linux security, by offering libraries that can be used by developers of third-party security solutions.
parallel task execution A process that determines the number of hosts on which tasks are executed at the same time.
pip The Python software installer. A Python-based way to install software packages using Python (and not yum) repositories.
pipelines See CI/CD.
play A collection of tasks that is executed on a specific host or group of hosts in an Ansible playbook. Each play has a play header, providing details on what exactly to do and on which hosts it should be done.
playbook A collection of one or more plays that is gathered in a playbook and contain tasks to be executed on specific hosts.
plug-in Pieces of code that augment Ansible core functionality.
pool A collection of software repositories in Red Hat Subscription Manager that a subscription offers an entitlement for.
project A collection of playbooks and other configurations used to manage a specific managed environment.
provisioning Deploying and installing systems.
public key fingerprint A short representation of a public key, which can be used to verify a public key.
Python A common scripting language. Ansible is written in Python.
R
random salt Random data that is added to a hash function as defined by the encryption algorithm to generate hashed data.
register A keyword that enables the result of a command to be stored in a variable.
requirements file A file that can be used to define multiple roles that should be installed.
RHEL system role An Ansible role created by Red Hat to standardize configuration tasks across different versions of Red Hat Enterprise Linux.
role A collection of variables, templates, modules, and tasks developed to perform a specific task and can be embedded in a playbook easily.
S
serial task execution A process that determines the number of hosts on which all tasks are executed before tasks will be executed on other hosts.
shell script An executable file, written in ASCII text, that contains commands which will be executed by the Linux Bash shell.
subscription An entitlement to use Red Hat software. Red Hat Enterprise Linux needs to be used with a subscription. Subscriptions are used to give users of RHEL access to software updates and optionally also support.
T–U
tag A label that can be set on tasks, blocks, plays, and roles, which allows users to run only specific parts of the playbook.
task A specification of a module and specific arguments needed to configure a desired state.
template A configuration file that contains variables and, based on the variables, is generated on the managed hosts according to host-specific requirements.
V
vault A secured environment that can be used to store variables in an encrypted way.
version control system A structure that enables developers to easily work on software code and manage different versions and patches of the code.
W–X
when A conditional statement that enables Ansible to run a specific task only if a specific condition is true.
WinRM Windows Remote Management; the Windows software that may be used to manage Windows with Ansible.
Y–
YAML The language that is used to write Ansible playbooks.