bdb856c8fe
1. Migrate Ops chapter and tips and tricks appendix to developer docs 2. Migrate Appendix G to a chapter in the developer docs 3. Minor edits Change-Id: I4070f02b75a8f9614545be0744e63ba76a3b49e2 Implements: blueprint osa-install-guide-overhaul
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===============
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Tips and tricks
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===============
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Ansible forks
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~~~~~~~~~~~~~
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The default MaxSessions setting for the OpenSSH Daemon is 10. Each Ansible
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fork makes use of a Session. By default, Ansible sets the number of forks to
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5. However, you can increase the number of forks used in order to improve
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deployment performance in large environments.
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Note that more than 10 forks will cause issues for any playbooks
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which use ``delegate_to`` or ``local_action`` in the tasks. It is
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recommended that the number of forks are not raised when executing against the
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Control Plane, as this is where delegation is most often used.
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The number of forks used may be changed on a permanent basis by including
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the appropriate change to the ``ANSIBLE_FORKS`` in your ``.bashrc`` file.
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Alternatively it can be changed for a particular playbook execution by using
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the ``--forks`` CLI parameter. For example, the following executes the nova
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playbook against the control plane with 10 forks, then against the compute
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nodes with 50 forks.
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.. code-block:: shell-session
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# openstack-ansible --forks 10 os-nova-install.yml --limit compute_containers
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# openstack-ansible --forks 50 os-nova-install.yml --limit compute_hosts
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For more information about forks, please see the following references:
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* OpenStack-Ansible `Bug 1479812`_
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* Ansible `forks`_ entry for ansible.cfg
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* `Ansible Performance Tuning`_
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.. _Bug 1479812: https://bugs.launchpad.net/openstack-ansible/+bug/1479812
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.. _forks: http://docs.ansible.com/ansible/intro_configuration.html#forks
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.. _Ansible Performance Tuning: https://www.ansible.com/blog/ansible-performance-tuning
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--------------
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.. include:: navigation.txt
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