Ansible Commands

Below are some frequently used Ansible commands for managing your servers.

List all hosts defined in the inventory file:

ansible --list-hosts all -i servers.ini
# or for YAML format
ansible --list-hosts all -i servers.yaml

Check the connectivity of all servers:

ansible -m ping all -i server.ini

Run a command (e.g., uptime) on all servers:

ansible -m command -a "uptime" all -i server.ini

Copy a file from the Ansible server to all target servers:

ansible -m copy -a "src=<file-location-on-ansible-server> dest=<destination-location-on-server>" all -i server.ini

Execute a command with elevated privileges (sudo) as the root user:

ansible -m command -a "uptime" all -i server.ini --become --become-user root --become-method sudo

Install the nginx package on all servers:

ansible -m apt -a "name=nginx state=present" --become --become-user root --become-method sudo

Remove the nginx package from all servers:

ansible -m apt -a "name=nginx state=absent" --become --become-user root --become-method sudo

Update the package list and upgrade all packages:

ansible -m apt -a "upgrade=yes update_cache=yes" --become --become-user root --become-method sudo

Advanced Usage and Notes

Module Limitations: The command module does not support special characters or shell features. For commands requiring shell features (like pipes or redirection), use the shell module.

Example:
```
ansible -m shell -a "cat /etc/passwd | grep -l" all -i server.ini --become
```
Raw Module: Use the raw module for devices that do not have Python installed. It allows you to execute raw SSH commands directly.

Example:
```
ansible -m raw -a "hostnamectl" all -i server.ini --become
```

Use the setup module to gather system facts from all servers:

ansible -m setup --become all -i server.ini

You can filter specific facts:

ansible -m setup -a "filter=ansible_memory" --become all -i server.ini
ansible -m setup -a "filter=ansible_distribution" --become all -i server.ini