Mastering Ansible: Core Architecture, Workflow, and Essential Commands

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; it can be extended with various programming languages.

1. Ansible Basic Architecture

Core: ansible

Core Modules: modules shipped with Ansible

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

Plugins: extend module functionality

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

Connection Plugins: enable connections via SSH and other methods

Host Inventory: definition of the hosts managed by Ansible

2. Ansible Working Principle

The management node can connect to managed nodes via local, SSH, or ZeroMQ; host inventory can be categorized by application type; ad‑hoc commands execute single modules on multiple hosts, while playbooks orchestrate multiple tasks for complex operations such as web service deployment or database backup.

3. Seven Ansible Commands

1. ansible

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

Executes ad‑hoc commands; default module is

command

. Example:

<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>

2. ansible-doc

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

Shows module documentation. List all modules:

<code># ansible-doc -l</code>

Show usage of a specific module (e.g.,

command

):

<code># ansible-doc -s command</code>

3. ansible-galaxy

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

Installs roles from Ansible Galaxy . 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

Runs a playbook file, the most frequently used command.

6. ansible-pull

Uses the pull mode (opposite of push) for scenarios with many machines or offline nodes.

7. ansible-vault

Encrypts/decrypts sensitive data in configuration files. Use with

--ask-vault-pass

when running playbooks that contain encrypted variables.