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How to Make Ansible Connection Parameters Dependent on the Controller Host?

I need to configure Ansible so that the connection parameters depend on the host from which Ansible is executed. Here are a few example scenarios:
1. When Ansible is run on the local host, it’s preferable to use a local connection with privilege escalation rather than SSH.
2. Some hosts may have non-standard firewall rules (e.g., using ProxyJump or non-standard SSH ports).
3. In virtualized or containerized environments, it might be necessary to use local tools (e.g., docker exec or oc rsh) to interact with services.
4. Different hosts may use different accounts for connections.

How can I properly organize Ansible execution based on the controller host?

Answers

Thank you for your ideas! Dynamic inventory indeed suits my needs. Also, the idea of using dynamic connection variables based on the controller host is very interesting — I will use it in my projects.

Another solution is to use dynamic variables based on the host from which Ansible is executed. This can be done using a construct like:

ansible_connection: "{{ 'local' if lookup('pipe', 'hostname') == 'myclient1' else 'ssh' }}"

This allows you to use a local connection for myclient1 and SSH connection for other hosts.

You can also use a dynamic inventory to automatically determine connection parameters based on the current host:

		
			
		
		#!/usr/bin/env python

import json

inventory = {
    'all': {
        'hosts': ['localhost', 'server1', 'container1'],
        'vars': {
            'ansible_become': 'yes'
        }
    },
    '_meta': {
        'hostvars': {
            'localhost': {
                'ansible_connection': 'local'
            },
            'server1': {
                'ansible_host': '192.0.2.10',
                'ansible_user': 'admin',
                'ansible_port': 2222,
                'ansible_ssh_common_args': '-o ProxyJump=jumphost'
            },
            'container1': {
                'ansible_connection': 'docker'
            }
        }
    }
}

print(json.dumps(inventory, indent=2))

Make the script executable and use it in Ansible:

		
			
		
		chmod +x dynamic_inventory.py
ansible-playbook -i dynamic_inventory.py playbook.yml

Yes, you can configure connection parameters based on the host by using variables in the inventory. For example:

		
			
		
		[all]
localhost ansible_connection=local ansible_become=yes
server1 ansible_host=192.0.2.10 ansible_user=admin ansible_port=2222 ansible_ssh_common_args='-o ProxyJump=jumphost'
container1 ansible_connection=docker

To apply different connection settings based on the controller host, you can use conditional statements in your playbooks.

Example:

		
			
		
		- hosts: all
  tasks:
    - name: For localhost
      debug:
        msg: "This is localhost"
      when: inventory_hostname == 'localhost'

    - name: For server1
      debug:
        msg: "This is server1"
      when: inventory_hostname == 'server1'

    - name: For container1
      debug:
        msg: "This is container1"
      when: inventory_hostname == 'container1'

Thank you for the ideas!