Using Ansible Playbook Command

1. Running Playbooks

Command	Description	Options	Example
ansible-playbook	Executes Ansible playbooks	Standard options like `-i`, `-l`, `--check`	`ansible-playbook site.yml -i inventory.ini`

Example: Running a playbook with inventory

ansible-playbook site.yml -i production.ini --check

Note: The --check flag runs the playbook in dry-run mode, showing what would change without actually making changes.

2. Checking Syntax

Example: Syntax Check

ansible-playbook --syntax-check site.yml

Option	Values	Description
--syntax-check	`true`	Validate playbook syntax without executing
--check	`false`	Run in check mode (dry-run)

Note: The --syntax-check flag validates YAML structure and playbook format, ensuring no runtime errors before execution.

3. Performing Dry Run

Example: Running a playbook with dry-run

ansible-playbook site.yml --check

Option	Description	Usage
--check	Run playbook in dry-run mode	Simulates changes without applying them
--diff	Show differences in changed files	Used with --check to show what would change

Note: Dry-run does not execute tasks but still loads and evaluates all variables and conditions.

Warning: Some modules may still perform actions during a dry-run, such as checking file existence or validating configuration syntax.

4. Showing Differences

Option	Values	Description
--diff	`-D`	Shows the differences in files changed by tasks
--diff-only	`-d`	Shows only the differences, not the full file content

Example: Using --diff flag

ansible-playbook site.yml --diff

Note: The --diff option is particularly useful when running playbooks that modify files, such as configuration files or templates. It helps in reviewing what changes were made.

5. Limiting Hosts

Use the --limit option to restrict playbook execution to specific hosts or groups.

Option	Description	Example
--limit	Restrict execution to specific hosts or groups	`ansible-playbook site.yml --limit webservers`
--limit	Use pattern matching to limit hosts	`ansible-playbook site.yml --limit 'webservers:<web1>'`

Example: Limiting to a specific host

ansible-playbook site.yml --limit web1.example.com

Example: Limiting to a host group

ansible-playbook site.yml --limit webservers

Example: Using pattern matching

ansible-playbook site.yml --limit 'webservers:<web1>'

6. Using Tags

Tag	Description	Usage
--tags	Run only tasks with specified tags	`ansible-playbook site.yml --tags "web"`
--skip-tags	Skip tasks with specified tags	`ansible-playbook site.yml --skip-tags "db"`

Example: Tagging Tasks

- name: "Install web server"
  apt:
    name: nginx
    state: present
  tags:
    - web
    - server

- name: "Configure database"
  template:
    src: db.conf.j2
    dest: /etc/db.conf
  tags:
    - db
    - config

Example: Running Specific Tags

ansible-playbook site.yml --tags "web"

ansible-playbook site.yml --tags "web,db"

ansible-playbook site.yml --skip-tags "test"

Note: Tags are useful for running subsets of a playbook during development or deployment.

7. Starting at Task

When running an Ansible playbook, you can start execution at a specific task using the --start-at-task option. This is useful for debugging or re-running a specific part of a playbook without executing all previous tasks.

Option	Description	Example
--start-at-task	Start playbook execution at a specific task name	`ansible-playbook site.yml --start-at-task="Install Apache"`

Example: Starting at a Specific Task

ansible-playbook site.yml --start-at-task="Configure Firewall"

Note: The task name must exactly match the name field of a task in your playbook.

Warning: If the specified task is not found, Ansible will exit with an error.

8. Setting Verbosity

Option	Values	Description
-v	`1`	Verbose mode, shows basic output
-vv	`2`	More verbose, shows task names and status
-vvv	`3`	Very verbose, includes task details and variables
-vvvv	`4`	Debug mode, shows all internal Ansible operations

Example: Running a playbook with verbose output

ansible-playbook site.yml -vv

9. Listing Tasks

Option	Values	Description
--list-tasks	`ansible-playbook`	List all tasks in a playbook without executing them
--list-tags	`ansible-playbook`	List all tags in a playbook without executing them
--list-hosts	`ansible-playbook`	List all hosts in a playbook without executing them

Example: Listing Tasks in a Playbook

ansible-playbook example.yml --list-tasks

Note: The --list-tasks option is useful for reviewing the order and structure of tasks before running a playbook.

10. Listing Hosts

Command	Description	Options	Example
ansible-playbook	List all hosts in inventory	`--list-hosts`	`ansible-playbook site.yml --list-hosts`
ansible-playbook	List all hosts in inventory with details	`--list-hosts` + `-v`	`ansible-playbook site.yml --list-hosts -v`

Example: Listing hosts in a playbook

ansible-playbook site.yml --list-hosts

Note: The --list-hosts option is useful for verifying which hosts are included in the inventory before running a playbook.

11. Using Extra Variables

Variable	Usage	Description
--extra-vars	`-e`	Pass extra variables to the playbook
--extra-vars	`--extra-vars "key=value"`	Set a single variable
--extra-vars	`--extra-vars "@file.json"`	Load variables from a JSON file
--extra-vars	`--extra-vars "@file.yml"`	Load variables from a YAML file

Example: Setting a variable with `-e`

ansible-playbook site.yml -e "environment=production"

Example: Loading variables from a file

ansible-playbook site.yml --extra-vars "@vars.json"

Note: Extra variables override inventory and group variables, but can be overridden by host_vars or group_vars.

12. Setting Inventory

Option	Values	Notes
inventory	`hosts.ini`	Path to inventory file
inventory	`hosts.yaml`	YAML format inventory file
inventory	`hosts.json`	JSON format inventory file
inventory	`inventory/`	Directory containing inventory files
inventory	`localhost,`	Static inventory with comma-separated hosts

Example: Static Inventory File (hosts.ini)

[webservers]
web1.example.com
web2.example.com

[databases]
db1.example.com
db2.example.com

[all:vars]
ansible_user=ubuntu
ansible_ssh_private_key_file=~/.ssh/id_rsa

Example: Dynamic Inventory Script

#!/bin/bash
# inventory.py - Dynamic inventory script for AWS EC2 instances

echo '{
  "ec2": {
    "hosts": [
      "10.0.1.100",
      "10.0.1.101"
    ],
    "vars": {
      "ansible_user": "ec2-user"
    }
  }
}'