Master 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; it can be extended with various programming languages.

1. Ansible Basic Architecture

The diagram shows that Ansible consists of the following components:

Core: Ansible itself

Core Modules: modules shipped with Ansible

Custom Modules: user‑added modules for extra functionality

Plugins: extensions that supplement module capabilities

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

Connection Plugins: enable connections to hosts via SSH and other methods

Host Inventory: definitions of the hosts managed by Ansible

2. Ansible Working Principle

Key points from the diagrams:

The control node can connect to managed hosts via local, SSH, or ZeroMQ, with SSH being the default (connection plugins).

Hosts can be grouped in the inventory by application type or other criteria; single‑module, single‑command batch execution is called ad‑hoc.

Playbooks allow multiple tasks to be combined into a single workflow, such as web service deployment or database backup, effectively chaining ad‑hoc operations.

3. Seven Essential Ansible Commands

After installing Ansible, you have the following seven commands. Below are their usage sections; detailed options can be obtained with the -h flag.

1. ansible

[root@localhost ~]# ansible -h
Usage: ansible [options]

The ansible command runs ad‑hoc commands on target hosts. By default it uses the command module unless another module is specified.

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

Default module can be changed in ansible.cfg.

2. ansible-doc

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

Shows module documentation. Common options are -l to list all modules and -s to display a module's syntax.

# ansible-doc -l

# ansible-doc -s command

3. ansible-galaxy

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

The command 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 tasks.

6. ansible-pull

Runs Ansible in pull mode, the opposite of the default push mode, useful for configuring a large number of machines or machines without network access.

7. ansible-vault

Encrypts and decrypts sensitive data in files. Encrypted files can be used in playbooks, requiring the --ask-vault-pass option at execution time.