How to trace and examine a hanging task?

[Thomas Steinbach]

Hello,

I am executing a huge playbook, which is hanging on following task:

- name: create default DVC

  docker:

    name: "{{ dapp_name }}-dvc"

    image: "{{ dapp_image }}:{{ dapp_version }}"

    state: present

By executing ps aux | grep vagrant that Ansible would processing following Python file:

vagrant   8260  0.0  0.5  55516 15976 pts/0    S+   18:33   0:00 /usr/bin/python /home/vagrant/.ansible/tmp/ansible-tmp-1455129213.02-267359423089921/docker

Question: Is there a possibility to trace back, why or at which point the execution of this script is hanging? Is there a possibility to reveal the past output of the process?

What I found out till now: I executed the python script manually and it immediately throws following error and hangs:

vagrant@vagrant-ubuntu-trusty-64:/tmp$ /usr/bin/python /home/vagrant/.ansible/tmp/ansible-tmp-1455129213.02-267359423089921/docker
/usr/local/lib/python2.7/dist-packages/docker/utils/utils.py:565: UserWarning: docker.utils.create_host_config() is deprecated. Please use Client.create_host_config() instead.

  'docker.utils.create_host_config() is deprecated. Please use '

This is the exact output of the execution. There is no more output but the cursor remains blinking and the script hangs. By the way, i am using the latest docker-py from pip:

vagrant@vagrant-ubuntu-trusty-64:/tmp$ pip show docker-py

---

Metadata-Version: 2.0

Name: docker-py

Version: 1.7.0

Summary: Python client for Docker.

Home-page: https://github.com/docker/docker-py/

Author: UNKNOWN

Author-email: UNKNOWN

License: UNKNOWN

Location: /usr/local/lib/python2.7/dist-packages

Requires: requests, six, websocket-client

[Thomas Steinbach]

This is not the answer to my question but I identified, why my playbook was hanging. The prablem was that docker hangs on pulling the image. I restarted the docker daemon and everything went fine.

Not that satisfying but a lesson learned.