AnsibleFest 2017, Network Modules in 2.3, and Ansible connection type

I had the opportunity to attend AnsibleFest 2017 in San Francisco. The sessions I attended were of high quality. It was well worth the cost of attendance.

One of the cool things the Ansible folks setup were “Ask an Expert” sessions. Attendees could sign up for a 15-minute appoitment to discuss whatever issues have been troubling you. I signed up for a session with a network-module author to talk about my recent struggles running network modules using Ansible 2.3.

In Ansible 2.3, network modules require connection: local. When I ran my existing playbooks using Ansible 2.3, I saw errors of the form:

invalid connection specified, expected connection=local, got smart

I spent a bunch of time online before AnsibleFest trying to find out why this was happening. I didn’t understand connection: local, and the documentation was vague. The expert at AnsibleFest set me straight. The explanation was so simple that I had a solid “duh!” moment.

connection: local simply means that the module being invoked will be run on the Ansible node. That’s it. The default, connection: remote, pushes the module’s Python code to the inventory host and executes it there. Starting in Ansible version 2.3, network modules enforce connection: local because they operate against inventory hosts that usually don’t have Python installed, e.g. SROS.

I’ve now adopted the following best practice:

  • Configure my inventory to set connection type for localhost to ‘local’
    • [local_host]
      localhost ansible_connection=local
  • Delegate tasks that I want to run on the Ansible host to localhost
    • delegate_to: localhost

 

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