Master Ansible: Core Architecture, How It Works, and 7 Essential Commands

Ansible is a model‑driven configuration manager that supports multi‑node deployment and remote task execution. It uses SSH by default, requires no additional software on managed nodes, and can be extended with various programming languages.

1. Ansible Basic Architecture

Core: ansible

Core Modules: modules shipped with Ansible

Custom Modules: user‑defined modules for additional functionality

Plugins: extend module capabilities

Playbooks: task configuration files that define multiple tasks

Connection Plugins: enable connections (SSH by default, plus others)

Host Inventory: defines the hosts managed by Ansible

2. How Ansible Works

The management side supports local, SSH, and ZeroMQ connections (SSH is default). Host inventories can be grouped by application type, enabling ad‑hoc commands for batch execution. Playbooks combine multiple tasks to implement functions such as web service deployment or database backup.

3. Seven Ansible Commands

After installing Ansible, you have seven primary commands: ansible, ansible-doc, ansible-galaxy, ansible-lint, ansible-playbook, ansible-pull, and ansible-vault. Below are their usage sections.

1. ansible

ansible -h

Used for ad‑hoc commands; the default module is command. Example:

[root@localhost ~]# ansible 192.168.0.102 -a 'date'
192.168.0.102 | success | rc=0 >>
Tue May 12 22:57:24 CST 2015

Parameters can be customized in ansible.cfg.

2. ansible-doc

ansible-doc -h
Usage: ansible-doc [options] [module...]

Shows module information. Examples: # ansible-doc -l Lists all installed modules. # ansible-doc -s command Displays usage of a specific module.

3. ansible-galaxy

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

Downloads third‑party roles from Ansible Galaxy , similar to yum or pip.

[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

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

Runs Ansible in pull mode, the opposite of the default push mode, suitable for large numbers of machines or offline nodes.

7. ansible-vault

Encrypts/decrypts sensitive variables in playbooks. Use the --ask-vault-pass option when running encrypted playbooks.