Run command on the Ansible host

I'd like to share that Ansible can be run on localhost via shell:

ansible all -i "localhost," -c local -m shell -a 'echo hello world'

This could be helpful for simple tasks or for some hands-on learning of Ansible.

The example of code is taken from this good article:

Running ansible playbook in localhost

You can use delegate_to to run commands on your Ansible host (admin host), from where you are running your Ansible play. For example:

Delete a file if it already exists on Ansible host:

 - name: Remove file if already exists
   file:
    path: /tmp/logfile.log
    state: absent
    mode: "u+rw,g-wx,o-rwx"
   delegate_to: 127.0.0.1

Create a new file on Ansible host :

 - name: Create log file
   file:
    path: /tmp/logfile.log
    state: touch
    mode: "u+rw,g-wx,o-rwx"
   delegate_to: 127.0.0.1

I've found a couple other ways you can write these which are a bit more readable IMHO.

    - name: check out a git repository
      local_action: 
        module: git
        repo: git://foosball.example.org/path/to/repo.git
        dest: /local/path

OR

    - name: check out a git repository
      local_action: git
      args:
        repo: git://foosball.example.org/path/to/repo.git
        dest: /local/path

Yes, you can run commands on the Ansible host. You can specify that all tasks in a play run on the Ansible host, or you can mark individual tasks to run on the Ansible host.

If you want to run an entire play on the Ansible host, then specify hosts: 127.0.0.1 and connection:local in the play, for example:

    - name: a play that runs entirely on the ansible host
      hosts: 127.0.0.1
      connection: local
      tasks:
      - name: check out a git repository
        git: repo=git://foosball.example.org/path/to/repo.git dest=/local/path

See Local Playbooks in the Ansible documentation for more details.

If you just want to run a single task on your Ansible host, you can use local_action to specify that a task should be run locally. For example:

    - name: an example playbook
      hosts: webservers
      tasks:
      - ...

      - name: check out a git repository
        local_action: git repo=git://foosball.example.org/path/to/repo.git dest=/local/path

See "Controlling where tasks run: delegation and local actions" in the Ansible documentation for more details.

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You can avoid having to type connection: local in your play by adding this to your inventory:

localhost ansible_connection=local

(Here you'd use "localhost" instead of "127.0.0.1" to refer to the play).

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In newer versions of Ansible, you no longer need to add the above line to your inventory, Ansible assumes it's already there.