Mastering Ansible: Architecture, Workflow, and Essential Commands Explained

Ansible is a model‑driven configuration manager that supports multi‑node deployment and remote task execution, using SSH by default and requiring no additional software on managed nodes.

1. Ansible Basic Architecture

The diagram shows that Ansible consists of the following parts:

Core: ansible

Core Modules: built‑in modules shipped with Ansible

Custom Modules: user‑added modules when core modules are insufficient

Plugins: extend module functionality

Playbooks: task configuration files that define multiple tasks for automated execution

Connection Plugins: enable various connection methods beyond the default SSH

Host Inventory: defines the managed hosts

2. Ansible Working Principle

From the diagrams we learn that the control node can connect to managed nodes via local, SSH, or ZeroMQ, with SSH being the default. Host inventory can be classified by application type, and modules perform the required operations. Single‑module, single‑command executions are called ad‑hoc. Playbooks combine multiple tasks to implement functions such as web service deployment or database backup.

3. Seven Ansible Commands

After installing Ansible, seven primary commands are available: ansible, ansible‑doc, ansible‑galaxy, ansible‑lint, ansible‑playbook, ansible‑pull, and ansible‑vault. Below are the usage sections for each.

1. ansible

<code>[root@localhost ~]# ansible -h
Usage: ansible [options]</code>

The

ansible

command executes ad‑hoc commands. By default it targets a host and runs the

command

module unless another module is specified.

<code>[[email protected] ~]# ansible 192.168.0.102 -a 'date'
192.168.0.102 | success | rc=0 >>
Tue May 12 22:57:24 CST 2015</code>

The default module can be changed in

ansible.cfg

. Parameter explanations are shown in the following diagrams:

2. ansible‑doc

<code>ansible-doc -h

Usage: ansible-doc [options] [module...]</code>

Used to view module information. Common options are

-l

to list all installed modules and

-s

to show details of a specific module, e.g.,

# ansible-doc -s command

.

3. ansible‑galaxy

<code>ansible-galaxy -h

Usage: ansible-galaxy [init|info|install|list|remove] [--help] [options] ...</code>

The command downloads third‑party roles from https://galaxy.ansible.com/, similar to yum or pip. Example:

<code>[root@localhost ~]# ansible-galaxy install aeriscloud.docker
- downloading role 'docker', owned by aeriscloud
- downloading role from https://github.com/AerisCloud/ansible-docker/archive/v1.0.0.tar.gz
- extracting aeriscloud.docker to /etc/ansible/roles/aeriscloud.docker
- aeriscloud.docker was installed successfully</code>

4. ansible‑lint

Checks playbook syntax:

ansible-lint playbook.yml

.

5. ansible‑playbook

The most frequently used command; it reads a playbook file and executes the defined actions.

6. ansible‑pull

Implements the pull mode, suitable for configuring a large number of machines or machines without network connectivity.

7. ansible‑vault

Encrypts and decrypts sensitive data in configuration files. Use the

--ask-vault-pass

option when running playbooks that contain vaulted variables.