What are Ansible roles?
- Ansible playbooks can be very similar: code used in one playbook can be useful in other playbooks also
- To make it easy to re-use the code, roles can be used.
- An Ansible role is composed of multiple folders, each of which contain several YAML files.
- By default, they have a main.yml file, but they can have more than one when needed.
Why and how we use Ansible?
Why Ansible?
- Ansible is free and Open Source.
- Agentless. Ansible doesn’t require any agent on client machines unlike other automation tool exists in the market (Puppet, Chef, Salt.). It uses SSH protocol to connect the servers. ...
- Ansible uses YAML language which is very easy to learn.
- Supported by Red Hat.
What is Ansible and how does it work?
How Ansible Works. Ansible is a radically simple IT automation engine that automates cloud provisioning, configuration management, application deployment, intra-service orchestration, and many other IT needs. Designed for multi-tier deployments since day one, Ansible models your IT infrastructure by describing how all of your systems inter-relate, rather than just managing one system at a time.
Why should you learn Ansible?
With Ansible, IT admins can begin automating away the drudgery from their daily tasks. Automation frees admins up to focus on efforts that help deliver more value to the business by speeding time to application delivery, and building on a culture of success. Ultimately, Ansible gives teams the one thing they can never get enough of: time.
What is Ansible in DevOps and why we use it?
That’s why Ansible is automation designed with everyone in mind. DevOps can help organizations that are pushing to implement a bimodal strategy to support their digitalization efforts. Ansible is the first human-readable automation language that can be read and written across IT.
How do you write roles in Ansible?
Follow the aforementioned steps to write a Role:Initialise the role structure using the command: ansible-galaxy init <role-name>Go to role directory using: cd <role-name>Initialise for Git: git init.Do the necessary changes required to add role functionality.Add files to Git using the command: git add *More items...•
How do you manage Ansible roles?
By default, Ansible looks for roles in two locations in a directory called roles/ within the directory where playbook resides or in the /etc/ansible/roles. If you wish to store roles at different paths, declare the paths using the - role: parameter in the playbook.
What is the difference between an Ansible role and a playbook?
Ansible playbook is a script file which contains all the tasks that need to be performed along with all the ingredients required to perform these tasks. Roles are ways of automatically certain var files, tasks, and handlers based on the known file structure.
What is Ansible Galaxy roles?
Ansible Galaxy is essentially a large public repository of Ansible roles. Roles ship with READMEs detailing the role's use and available variables. Galaxy contains a large number of roles that are constantly evolving and increasing. Galaxy can use git to add other role sources, such as GitHub.
Where are Ansible roles stored?
Ansible will search for roles in the following way: A roles/ directory, relative to the playbook file. By default, in /etc/ansible/roles.
What is the role of Ansible in Devops?
Ansible is an open source IT Configuration Management, Deployment & Orchestration tool. It aims to provide large productivity gains to a wide variety of automation challenges. This tool is very simple to use yet powerful enough to automate complex multi-tier IT application environments.
What are types of Ansible?
Ansible has 3 main scopes: Global: this is set by config, environment variables and the command line. Play: each play and contained structures, vars entries, include_vars, role defaults and vars. Host: variables directly associated to a host, like inventory, facts or registered task outputs.
What is host group in Ansible?
Ansible uses a combination of a hosts file and a group_vars directory to pull variables per host group and run Ansible plays/tasks against hosts. group_vars/all is used to set variables that will be used for every host that Ansible is ran against.
What is a playbook Ansible?
Ansible Playbooks are lists of tasks that automatically execute against hosts. Groups of hosts form your Ansible inventory. Each module within an Ansible Playbook performs a specific task. Each module contains metadata that determines when and where a task is executed, as well as which user executes it.
What are Ansible modules?
Ansible modules are reusable, standalone scripts that can be used by the Ansible API, or by the ansible or ansible-playbook programs. They return information to ansible by printing a JSON string to stdout before exiting. They take arguments in one of several ways which we'll go into as we work through this tutorial.
What is Ansible vault?
Ansible Vault is an Ansible feature that helps you encrypt confidential information without compromising security.
How do you use handlers in Ansible roles?
In a nutshell, handlers are special tasks that only get executed when triggered via the notify directive. Handlers are executed at the end of the play, once all tasks are finished. In Ansible, handlers are typically used to start, reload, restart, and stop services.
How do I add a role in playbook?
In this section, we will separate the major parts of your playbook, including vars: , tasks: , template: , and handlers: .Step 1: Backup. ... Step 2: Add play definition/Invoke role. ... Step 3: Add default variables. ... Step 4: Add variables. ... Step 5: Create role handler. ... Step 6: Add role tasks. ... Step 7: Download templates.
How are variables defined in Ansible roles?
Variable Name Rules Ansible has a strict set of rules to create valid variable names. Variable names can contain only letters, numbers, and underscores and must start with a letter or underscore. Some strings are reserved for other purposes and aren't valid variable names, such as Python Keywords or Playbook Keywords.
Which is the first place Ansible checks for a role definition?
The meta directory contains authorship information which is useful if you choose to publish your role on galaxy.ansible.com. The meta directory may also be used to define role dependencies.
What is ansible role?
Ansible roles are simple but robust features of Ansible that organize a group of variables, tasks, files, handlers, dependencies in a standardized file structure. We can create a skeleton of any role using ‘ansible-galaxy’.
What are roles in Ansible?
Ansible roles are used to simplify Ansible playbook which means we can break a complex Ansible playbook in independent and reusable roles that are used to automatically load certain var_files, tasks, and handlers as per pre-defined file structure. We can call the roles in any Ansible playbook as it is reusable and independent of each other. We can also share the configuration template using roles easily. As mentioned roles need a standardized file structure that means at least one of the directories exists and must have a main.yml however we can remove other directories if not in use. The default location of roles is “/etc/ansible/roles”.
Do roles keep tasks?
Tasks: We keep our tasks or the plays that will be performed by the roles however we can keep tasks in other folders separately as well for readability and better manageability and can be added to the roles using include if required. If this directory is being used in the role then it must contain main.yml.
Can Meta configure role dependencies?
Meta: We can configure role dependencies and other configurations such as allow_duplicates etc.
How does Ansible handle duplicate roles?
Ansible treats duplicate role dependencies like duplicate roles listed under roles:: Ansible only executes role dependencies once, even if defined multiple times, unless the parameters, tags, or when clause defined on the role are different for each definition. If two roles in a playbook both list a third role as a dependency, Ansible only runs that role dependency once, unless you pass different parameters, tags, when clause, or use allow_duplicates: true in the role you want to run multiple times. See Galaxy role dependencies for more details.
How many times does Ansible run a role?
Ansible only executes each role once, even if you define it multiple times, unless the parameters defined on the role are different for each definition. For example, Ansible only runs the role foo once in a play like this: --- - hosts: webservers roles: - foo - bar - foo.
Why does Ansible run foo twice?
In these examples, Ansible runs foo twice because each role definition has different parameters.
What does roles/x/handlers/main.yml do?
If roles/x/handlers/main.yml exists, Ansible adds the handlers in that file to the play.
What is role dependencies?
Role dependencies are prerequisites, not true dependencies. The roles do not have a parent/child relationship. Ansible loads all listed roles, runs the roles listed under dependencies first, then runs the role that lists them. The play object is the parent of all roles, including roles called by a dependencies list.
How many directories are there in Ansible?
An Ansible role has a defined directory structure with eight main standard directories. You must include at least one of these directories in each role. You can omit any directories the role does not use. For example:
What is tasks/main.yml?
tasks/main.yml - the main list of tasks that the role executes.
Where are roles stored?
Roles are stored in separate directories and have a particular directory structure
What is a role in a playbook?
The role is the primary mechanism for breaking a playbook into multiple files. This simplifies writing complex playbooks and makes them easier to reuse.
Can you change the default structure of roles?
The roles have a structured layout on the file system. You can change the default structured of the roles as well.
Why use ansible roles?
Ansible Roles helps in modulation, and for a developer, it’s much easier to manage these roles. Ansible roles are reused multiple times within a playbook, and without a need to update the complete playbook, a developer can only update the specific Ansible Roles.
What is ansible software?
Ansible is an open-source IT automation engine. It helps in application deployment automation, configuration management, service orchestration, and cloud provisioning. Ansible is designed for a multi-tier environment that models IT infrastructure. Ansible uses playbooks in the YAML language to describe automation jobs. YAML language is easier to understand by both humans and computers. Ansible works by pushing out small programs called Modules by connecting to your nodes.
Can Ansible be run on Linux?
Since the Ansible Control node cannot be a Windows machine, we will use Linux (Ubuntu) for running Ansible. I have used the AWS EC2 instance to run Ubuntu, but you can also run it on your Ubuntu systems. I will assume that you have already created an Ubuntu EC2 instance on AWS. Now start your Ubuntu instance and follow the steps for Ansible install and configuration. If you are running Ubuntu on your own system, then open the Terminal for installing Ansible. You can skip the below steps if you already have Ansible on your system.
Can you create roles in Ansible?
After installing Ansible on your Ubuntu system, you are ready to create Ansible Roles. Now, see the below steps to create it in your system.
Can you use your own Ansible playbook?
But you can use your own Ansible playbook too.
What is ansible role?
Ansible roles are basically a collection of files, tasks, templates, variables, and modules. It is used for breaking a playbook into multiple files. This will helps you to write a complex playbook and make it easier to reuse.
What are the advantages of using roles in Ansible?
One of the advantages of using the roles is that we do not have to worry about importing tasks and variables. Ansible automatically imports all tasks from the tasks folder and all variables from the vars folder. The other folders are used for storing supporting files, templates, and handlers.
What is ansible role?
Ansible role is a set of tasks to configure a host to serve a certain purpose like configuring a service. Roles are defined using YAML files with a predefined directory structure. The concept of an Ansible role is simple; it is a group of variables, tasks, files, and handlers that are stored in a standardized file structure.
Can Ansible run standalone?
It can run standalone using `ansible` ad-hoc command or `ansible-playbook` to run a playbook script. Ansible Tower has a free basic 10 node license. This allows you load ansible playbook projects, run playbooks, schedule playbooks, handle inventories of servers, and a full ACL for managing users.
What is the default role name in Galaxy?
Starting in v3.0, Galaxy no longer perform this calculation. Instead, the default role name is the unaltered repository name, with a couple minor exceptions, including: converting the name to all lowercase, and replacing any ‘-‘ or ‘.’ characters with ‘_’ .
What characters are allowed in role names?
Role names are limited to lowercase word characters (i.e., a-z, 0-9) and ‘_’. No special characters are allowed, including ‘.’, ‘-‘, and space. During import, any ‘.’ and ‘-‘ characters contained in the repository name or role_name will be replaced with ‘_’.
What happens if no value is provided in a role?
If no value is provided, then the role name will match the repository name, with a couple of exceptions, including: converting the name to all lowercase, and replacing any ‘-‘ or ‘.’ characters with ‘_’.
When are dependencies installed?
dependencies. Optional. In a nutshell, dependencies are installed when the role is installed, and dependencies are executed before the role is executed. During role install and execution, dependencies are recursive, meaning dependencies can have dependencies.
Is role_name used in Git?
role_name is not used at all if the role is installed using its Git URL. Instead, the name of the repo is used.
Can you search by name in Ansible?
As with platforms, you can search by name here as well. For example, to see if the ‘database’ tag exists, add ? name_icontains=database to the query. The full URL will be https://galaxy.ansible.com/api/v1/tags/?name__icontains=database.
Does Galaxy remove anansible-role-apache?
In the past, Galaxy would apply a regex expression to the GitHub repository name and automatically remove ‘ansible-‘ and ‘ansible-role-‘. For example, if your repository name was ‘ansible-role-apache’, the role name would translate to ‘apache’. Galaxy no longer does this automatically. Instead, use the role_name setting to tell Galaxy what the role name should be.
Why is Ansible important?
This feature is important because your requirements for running a task may depend on the state of a service, existence of a file or a follow up tasks when state changed. We can make use of variables in notify ...
Is it useful to run a task on the basis of a remote node?
As we know that value of these variables differs from one remote host to another, so making decision to run task on basis of the fact of a remote node is useful.
Do Ansible handlers have the same contents as tasks?
Ansible handlers have same contents as a task can have.
