8fc8372e74
Adds a wait step to allow for finer grained workflows and forcing interruptions which may be needed in some cases with specialized hardware. Change-Id: Idc338b761ebe35a4635022a324ca5acbf29fc462
102 lines
4.8 KiB
ReStructuredText
102 lines
4.8 KiB
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=====
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Steps
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=====
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What are steps?
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===============
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Steps are exactly that, steps to achieve a goal, and in most cases, they
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are what an operator requested.
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However, originally they were the internal list of actions to achieve to
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perform *automated cleaning*. The conductor would determine a list of
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steps or actions to take by generating a list of steps from data the
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conductor via drivers, the ``ironic-python-agent``, and any loaded
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hardware managers determined to be needed.
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As time passed and Ironic's capabilities were extended, this was extended
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to *manual cleaning*, and later into *deploy steps*, and *deploy templates*
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allowing an operator to request for firmware to be updated by a driver, or
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RAID to be configured by the agent prior to the machine being released
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to the end user for use.
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Reserved Functional Steps
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=========================
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In the execution of the cleaning, and deployment steps frameworks, some step
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names are reserved for specific functions which can be invoked by a user to
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perform specific actions.
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+-----------+----------------------------------------------------------+
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| Step Name | Description |
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+-----------+----------------------------------------------------------+
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| hold | Pauses the execution of the steps by moving the node |
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| | from the current ``deploy wait`` or ``clean wait`` state |
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| | to the appropriate "hold" state, such as ``deploy hold`` |
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| | or ``clean hold``. The process can be resumed by sending |
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| | a ``unhold`` verb to the provision state API endpoint |
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| | which will result in the process resuming upon the next |
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| | heartbeat operation. During this time, heartbeat |
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| | operations will continue be recorded by Ironic, but will |
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| | not be acted upon, preventing the node from timing out. |
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| | |
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| | This step cannot be used against a child node in the |
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| | context of being requested when executing against a |
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| | parent node. |
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| | |
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| | The use case for this verb is if you have external |
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| | automation or processes which need to be executed in the |
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| | entire process to achieve the overall goal. |
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+-----------+----------------------------------------------------------+
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| power_on | Powers on the node, which may be useful if a node's |
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| | power must be toggled multiple times to enable |
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| | embedded behavior such as to boot from network. |
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| | This step can be executed against child nodes. |
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+-----------+----------------------------------------------------------+
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| power_off | Turn the node power off via the conductor. |
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| | This step can be used against child nodes. When used |
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| | outside of the context of a child node, any agent token |
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| | metadata is also removed as so the machine can reboot |
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| | back to the agent, if applicable. |
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+-----------+----------------------------------------------------------+
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| reboot | Reboot the node utilizing the conductor. This generally |
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| | signals for power to be turned off and back on, however |
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| | driver specific code may request an CPU interrupt based |
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| | reset. This step can be executed on child nodes. |
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+-----------+----------------------------------------------------------+
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| wait | Causes a brief pause in the overall step execution which |
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| | pauses until the next heartbeat operation, unless a |
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| | seconds argument is provided. If a *seconds* argument is |
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| | provided, then the step execution will pause for the |
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| | requested amount of time. |
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+-----------+----------------------------------------------------------+
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In the these cases, the interface upon which the method is expected is
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ignored, and the step is acted upon based upon just the step's name.
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Example
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-------
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In this example, we utilize the cleaning step ``erase_devices`` and then
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trigger hold of the node. In this specific case the node will enter
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a ``clean hold`` state.
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.. code-block:: json
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{
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"target":"clean",
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"clean_steps": [{
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"interface": "deploy",
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"step": "erase_devices"
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},
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{
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"interface": "deploy",
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"step": "hold"
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}]
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}
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Once you have completed whatever action which needed to be performed while
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the node was in a held state, you will need to issue an unhold provision
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state command, via the API or command line to inform the node to proceed.
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