Asynchronous Actions and Polling ================================ By default tasks in playbooks block, meaning the connections stay open until the task is done on each node. This may not always be desirable, or you may be running operations that take longer than the SSH timeout. The easiest way to do this is to kick them off all at once and then poll until they are done. You will also want to use asynchronous mode on very long running operations that might be subject to timeout. To launch a task asynchronously, specify its maximum runtime and how frequently you would like to poll for status. The default poll value is 10 seconds if you do not specify a value for `poll`:: --- - hosts: all remote_user: root tasks: - name: simulate long running op (15 sec), wait for up to 45 sec, poll every 5 sec command: /bin/sleep 15 async: 45 poll: 5 .. note:: There is no default for the async time limit. If you leave off the 'async' keyword, the task runs synchronously, which is Ansible's default. Alternatively, if you do not need to wait on the task to complete, you may run the task asynchronously by specifying a poll value of 0:: --- - hosts: all remote_user: root tasks: - name: simulate long running op, allow to run for 45 sec, fire and forget command: /bin/sleep 15 async: 45 poll: 0 .. note:: You shouldn't attempt run a task asynchronously by specifying a poll value of 0:: to with operations that require exclusive locks (such as yum transactions) if you expect to run other commands later in the playbook against those same resources. .. note:: Using a higher value for ``--forks`` will result in kicking off asynchronous tasks even faster. This also increases the efficiency of polling. If you would like to perform a task asynchroniusly and check on it later you can perform a task similar to the following:: --- # Requires ansible 1.8+ - name: 'YUM - async task' yum: name: docker-io state: installed async: 1000 poll: 0 register: yum_sleeper - name: 'YUM - check on async task' async_status: jid: "{{ yum_sleeper.ansible_job_id }}" register: job_result until: job_result.finished retries: 30 .. note:: If the value of ``async:`` is not high enough, this will cause the "check on it later" task to fail because the temporary status file that the ``async_status:`` is looking for will not have been written or no longer exist If you would like to run multiple asynchronous tasks while limiting the amount of tasks running concurrently, you can do it this way:: ##################### # main.yml ##################### - name: Run items asynchronously in batch of two items vars: sleep_durations: - 1 - 2 - 3 - 4 - 5 durations: "{{ item }}" include_tasks: execute_batch.yml loop: - "{{ sleep_durations | batch(2) | list }}" ##################### # execute_batch.yml ##################### - name: Async sleeping for batched_items command: sleep {{ async_item }} async: 45 poll: 0 loop: "{{ durations }}" loop_control: loop_var: "async_item" register: async_results - name: Check sync status async_status: jid: "{{ async_result_item.ansible_job_id }}" loop: "{{ async_results.results }}" loop_control: loop_var: "async_result_item" register: async_poll_results until: async_poll_results.finished retries: 30 .. seealso:: :doc:`playbooks` An introduction to playbooks `User Mailing List <http://groups.google.com/group/ansible-devel>`_ Have a question? Stop by the google group! `irc.freenode.net <http://irc.freenode.net>`_ #ansible IRC chat channel