Ansible Common Commands Summary

1. Basic Syntax

ansible <target host or group> -m <module name> -a "<module parameters>"

•<target host or group>: Can be a host, host group in Inventory, or all to indicate all hosts.•-m <module name>: Specifies the module to use (e.g., ping, shell, yum, etc.).•-a "<module parameters>": Parameters passed to the module.

2. Common Options

Option	Description
`<span>-i <Inventory file></span>`	Specify a custom Inventory file (default is `<span>/etc/ansible/hosts</span>`).
`<span>-u <username></span>`	Specify the login user for the remote host (default is the current user).
`<span>-k</span>`	Prompt for SSH password (if SSH key is not configured).
`<span>--become</span>`	Privilege escalation to execute tasks (default uses `<span>sudo</span>`).
`<span>--become-user</span>`	Specify the user for privilege escalation (default is `<span>root</span>`).
`<span>-K</span>`	Prompt for privilege escalation password (e.g., `<span>sudo</span>` password).
`<span>-f <concurrency></span>`	Specify the number of concurrent processes (default is 5).
`<span>-v</span>`	Display verbose output (`<span>-vvv</span>` shows more detailed information).
`<span>--check</span>`	Dry run, simulating execution without actually performing tasks.
`<span>--diff</span>`	Show differences in files or configurations (usually used with `<span>--check</span>`).

3. Common Ad-hoc Command Examples

3.1 Check Host Connectivity

ansible all -m ping

3.2 Execute Commands on All Hosts

# Execute uptime command
ansible all -a "uptime"
# Execute shell command
ansible all -m shell -a "df -h"

3.3 Manage Packages

# Install package (using yum module)
ansible webservers -m yum -a "name=httpd state=present"
# Uninstall package
ansible webservers -m yum -a "name=httpd state=absent"

3.4 Manage Services

# Start service
ansible webservers -m service -a "name=httpd state=started"
# Stop service
ansible webservers -m service -a "name=httpd state=stopped"
# Restart service
ansible webservers -m service -a "name=httpd state=restarted"

3.5 File Operations

# Copy file
ansible webservers -m copy -a "src=/local/path/file.txt dest=/remote/path/file.txt"
# Change file permissions
ansible webservers -m file -a "path=/remote/path/file.txt mode=644 owner=root group=root"
# Create directory
ansible webservers -m file -a "path=/remote/path/new_dir state=directory"

3.6 User Management

# Create user
ansible all -m user -a "name=testuser password=123456"
# Delete user
ansible all -m user -a "name=testuser state=absent"

3.7 Cron Job Management

# Add cron job
ansible all -m cron -a "name='backup' minute=0 hour=2 job='/path/to/backup.sh'"
# Delete cron job
ansible all -m cron -a "name='backup' state=absent"

3.8 Privilege Escalation to Execute Tasks

# Execute command using sudo
ansible all --become -a "yum update -y"
# Specify privilege escalation user
ansible all --become --become-user=admin -a "whoami"

3.9 Check Host Information

# Gather host information (using setup module)
ansible all -m setup
# View specific information (e.g., IP address)
ansible all -m setup -a "filter=ansible_default_ipv4"

3.10 Dry Run

# Simulate executing a task
ansible all -m yum -a "name=httpd state=present" --check

4. Advanced Usage

4.1 Using Variables

ansible all -m ping debug -a "msg='Hello, {{ ansible_hostname }}'"

4.2 Limiting Executing Hosts

# Execute only on specific host
ansible web1.example.com -m ping
# Use pattern matching
ansible 'web*' -m ping

4.3 Concurrent Execution

# Specify concurrency to 10
ansible all -m ping -f 10

4.4 Using Tags

# Run tasks with specific tags only
ansible-playbook playbook.yml --tags "apache"

4.5 Using Ansible Vault to Encrypt Data

# Run tasks that require Vault password
ansible all -m debug -a "msg='{{ vault_var }}'" --ask-vault-pass

5. Common Modules

Module Name	Description
`<span>ping</span>`	Check host connectivity.
`<span>shell</span>`	Execute shell commands.
`<span>command</span>`	Execute commands (does not support pipes and redirection).
`<span>yum</span>`	Manage RPM packages (CentOS/RHEL).
`<span>apt</span>`	Manage DEB packages (Debian/Ubuntu).
`<span>service</span>`	Manage system services.
`<span>copy</span>`	Copy files to remote hosts.
`<span>file</span>`	Manage files and directories.
`<span>user</span>`	Manage users.
`<span>cron</span>`	Manage cron jobs.
`<span>setup</span>`	Gather host information.
`<span>debug</span>`	Debug output.

6. Notes

1.Module Selection: Prefer using Ansible modules instead of executing commands directly, as modules have idempotency (consistent results across multiple executions).2.Privilege Operations: If privilege escalation is needed, remember to use --become or -b options.3.Concurrency Control: Control concurrency with -f parameter to avoid overwhelming target hosts.4.Security: Avoid passing sensitive information (like passwords) directly in Ad-hoc commands; use Ansible Vault for encryption.

Editor: HoKoly

Supervisor:HoKoly

Reviewer:HoKoly