e240a29a92
Sometimes there is a need to develop site specific playbooks. Currently, it is necessary to manually invoke these at the right point during the deployment. Adding the ability to automatically run these custom playbooks will reduce the chance of running these playbooks at the wrong point or forgetting to run them at all. Change-Id: I1ae0f1f94665925326c8b1869dd75038f6f1b87d Story: 2001663 Task: 12606
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7.1 KiB
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204 lines
7.1 KiB
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========================
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Custom Ansible Playbooks
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========================
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Kayobe supports running custom Ansible playbooks located outside of the kayobe
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project. This provides a flexible mechanism for customising a control plane.
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Access to the kayobe variables is possible, ensuring configuration does not
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need to be repeated.
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Kayobe Custom Playbook API
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==========================
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Explicitly allowing users to run custom playbooks with access to the kayobe
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variables elevates the variable namespace and inventory to become an interface.
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This raises questions about the stability of this interface, and the guarantees
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it provides.
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The following guidelines apply to the custom playbook API:
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* Only variables defined in the kayobe configuration files under ``etc/kayobe``
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are supported.
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* The groups defined in ``etc/kayobe/inventory/groups`` are supported.
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* Any change to a supported variable (rename, schema change, default value
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change, or removal) or supported group (rename or removal) will follow a
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deprecation period of one release cycle.
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* Kayobe's internal roles may not be used.
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Note that these are guidelines, and exceptions may be made where appropriate.
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Running Custom Ansible Playbooks
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================================
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Run one or more custom ansible playbooks::
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(kayobe) $ kayobe playbook run <playbook>[, <playbook>...]
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Playbooks do not by default have access to the Kayobe playbook group variables,
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filter plugins, and test plugins, since these are relative to the current
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playbook's directory. This can be worked around by creating symbolic links to
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the Kayobe repository from the Kayobe configuration.
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Packaging Custom Playbooks With Configuration
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=============================================
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The kayobe project encourages its users to manage configuration for a cloud
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using version control, based on the `kayobe-config repository
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<https://opendev.org/openstack/kayobe-config>`_. Storing custom Ansible
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playbooks in this repository makes a lot of sense, and kayobe has special
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support for this.
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It is recommended to store custom playbooks in
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``$KAYOBE_CONFIG_PATH/ansible/``. Roles located in
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``$KAYOBE_CONFIG_PATH/ansible/roles/`` will be automatically available to
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playbooks in this directory.
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With this directory layout, the following commands could be used to create
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symlinks that allow access to Kayobe's filter plugins, group variables and test
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plugins:
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.. code-block:: console
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cd ${KAYOBE_CONFIG_PATH}/ansible/
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ln -s ../../../../kayobe/ansible/filter_plugins/ filter_plugins
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ln -s ../../../../kayobe/ansible/group_vars/ group_vars
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ln -s ../../../../kayobe/ansible/test_plugins/ test_plugins
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These symlinks can even be committed to the kayobe-config Git repository.
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Ansible Galaxy
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--------------
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Ansible Galaxy provides a means for sharing Ansible roles. Kayobe
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configuration may provide a Galaxy requirements file that defines roles to be
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installed from Galaxy. These roles may then be used by custom playbooks.
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Galaxy role dependencies may be defined in
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``$KAYOBE_CONFIG_PATH/ansible/requirements.yml``. These roles will be
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installed in ``$KAYOBE_CONFIG_PATH/ansible/roles/`` when bootstrapping the
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Ansible control host::
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(kayobe) $ kayobe control host bootstrap
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And updated when upgrading the Ansible control host::
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(kayobe) $ kayobe control host upgrade
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Example
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=======
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The following example adds a ``foo.yml`` playbook to a set of kayobe
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configuration. The playbook uses a Galaxy role, ``bar.baz``.
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Here is the kayobe configuration repository structure::
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etc/kayobe/
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ansible/
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foo.yml
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requirements.yml
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roles/
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bifrost.yml
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...
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Here is the playbook, ``ansible/foo.yml``::
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---
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- hosts: controllers
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roles:
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- name: bar.baz
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Here is the Galaxy requirements file, ``ansible/requirements.yml``::
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---
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- bar.baz
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We should first install the Galaxy role dependencies, to download the
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``bar.baz`` role::
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(kayobe) $ kayobe control host bootstrap
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Then, to run the ``foo.yml`` playbook::
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(kayobe) $ kayobe playbook run $KAYOBE_CONFIG_PATH/ansible/foo.yml
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Hooks
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=====
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.. warning::
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Hooks are an experimental feature and the design could change in the future.
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You may have to update your config if there are any changes to the design.
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This warning will be removed when the design has been stabilised.
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Hooks allow you to automatically execute custom playbooks at certain points during
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the execution of a kayobe command. The point at which a hook is run is referred to
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as a ``target``. Please see the :ref:`list of available targets<Hook Targets>`.
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Hooks are created by symlinking an existing playbook into the the relevant directory under
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``$KAYOBE_CONFIG_PATH/hooks``. Kayobe will search the hooks directory for sub-directories
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matching ``<command>.<target>.d``, where ``command`` is the name of a kayobe command
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with any spaces replaced with dashes, and ``target`` is one of the supported targets for
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the command.
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For example, when using the command::
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(kayobe) $ kayobe control host bootstrap
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kayobe will search the paths:
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- ``$KAYOBE_CONFIG_PATH/hooks/control-host-bootstrap/pre.d``
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- ``$KAYOBE_CONFIG_PATH/hooks/control-host-bootstrap/post.d``
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Any playbooks listed under the ``pre.d`` directory will be run before kayobe executes
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its own playbooks and any playbooks under ``post.d`` will be run after. You can affect
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the order of the playbooks by prefixing the symlink with a sequence number. The sequence
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number must be separated from the hook name with a dash. Playbooks with smaller sequence
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numbers are run before playbooks with larger ones. Any ties are broken by alphabetical
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ordering.
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For example to run the playbook ``foo.yml`` after ``kayobe overcloud host configure``,
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you could do the following::
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(kayobe) $ mkdir -p $KAYOBE_CONFIG_PATH/hooks/overcloud-host-configure/post.d
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(kayobe) $ ln -s $KAYOBE_CONFIG_PATH/ansible/foo.yml \
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$KAYOBE_CONFIG_PATH/hooks/overcloud-host-configure/post.d/10-foo.yml
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The sequence number for the ``foo.yml`` playbook is ``10``.
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Failure handling
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----------------
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If the exit status of any playbook, including built-in playbooks and custom hooks,
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is non-zero, kayobe will not run any subsequent hooks or built-in kayobe playbooks.
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Ansible provides several methods for preventing a task from producing a failure. Please
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see the `Ansible documentation <https://docs.ansible.com/ansible/latest/user_guide/playbooks_error_handling.html>`_
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for more details. Below is an example showing how you can use the ``ignore_errors`` option
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to prevent a task from causing the playbook to report a failure::
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---
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- name: Failure example
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hosts: localhost
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tasks:
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- name: Deliberately fail
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fail:
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ignore_errors: true
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A failure in the ``Deliberately fail`` task would not prevent subsequent tasks, hooks,
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and playbooks from running.
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.. _Hook Targets:
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Targets
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-------
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The following targets are available for all commands:
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.. list-table:: all commands
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:widths: 10 500
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:header-rows: 1
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* - Target
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- Description
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* - pre
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- Runs before a kayobe command has start executing
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* - post
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- Runs after a kayobe command has finished executing
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