cb8366d70c
To support the use case where one has multiple pools providing metastatic backing nodes, and those pools are in different regions, and a user wishes to use Zuul executor zones to communicate with whatever metastatic nodes eventually produced from those regions, this change updates the launcher and metastatic driver to use the node attributes (where zuul executor region names are specified) as default values for metastatic node attributes. This lets users configure nodepool with zuul executor zones only on the backing pools. Change-Id: Ie6bdad190f8f0d61dab0fec37642d7a078ab52b3 Co-Authored-By: Benedikt Loeffler <benedikt.loeffler@bmw.de>
156 lines
5.1 KiB
ReStructuredText
156 lines
5.1 KiB
ReStructuredText
.. _metastatic-driver:
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.. default-domain:: zuul
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Metastatic Driver
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-----------------
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This driver uses NodePool nodes (from any driver) as backing nodes to
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further allocate "static-like" nodes for end use.
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A typical use case is to be able to request a large node (a `backing
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node`) from a cloud provider, and then divide that node up into
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smaller nodes that are actually used (`requested nodes`). A backing
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node can support one or more requested nodes, and backing nodes are
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scaled up or down as necessary based on the number of requested
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nodes.
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The name is derived from the nodes it provides (which are like
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"static" nodes) and the fact that the backing nodes come from NodePool
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itself, which is "meta".
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.. attr-overview::
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:prefix: providers.[metastatic]
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:maxdepth: 3
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.. attr:: providers.[metastatic]
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:type: list
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A metastatic provider's resources are partitioned into groups
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called `pools`, and within a pool, the node types which are to be
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made available are listed.
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.. note:: For documentation purposes the option names are prefixed
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``providers.[metastatic]`` to disambiguate from other
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drivers, but ``[metastatic]`` is not required in the
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configuration (e.g. below
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``providers.[metastatic].pools`` refers to the ``pools``
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key in the ``providers`` section when the ``metastatic``
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driver is selected).
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Example:
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.. code-block:: yaml
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providers:
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- name: meta-provider
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driver: metastatic
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pools:
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- name: main
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max-servers: 10
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labels:
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- name: small-node
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backing-label: large-node
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max-parallel-jobs: 2
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grace-time: 600
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.. attr:: name
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:required:
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A unique name for this provider configuration.
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.. attr:: pools
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:type: list
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A pool defines a group of resources from the provider. Each pool has a
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maximum number of nodes which can be launched from it, along with a number
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of attributes that characterize the use of the backing nodes.
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.. attr:: name
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:required:
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A unique name within the provider for this pool of resources.
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.. attr:: priority
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:type: int
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:default: 100
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The priority of this provider pool (a lesser number is a higher
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priority). Nodepool launchers will yield requests to other
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provider pools with a higher priority as long as they are not
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paused. This means that in general, higher priority pools will
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reach quota first before lower priority pools begin to be used.
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This setting may be specified at the provider level in order
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to apply to all pools within that provider, or it can be
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overridden here for a specific pool.
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.. attr:: node-attributes
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:type: dict
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A dictionary of key-value pairs that will be stored with the
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node data in ZooKeeper. The keys and values can be any
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arbitrary string.
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The metastatic driver will automatically use the values
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supplied by the backing node as default values. Any values
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specified here for top-level dictionary keys will override
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those supplied by the backing node.
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.. attr:: max-servers
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:type: int
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Maximum number of servers spawnable from this pool. This can
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be used to limit the number of servers. If not defined
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nodepool can create as many servers that the backing node
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providers support.
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.. attr:: labels
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:type: list
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Each entry in a pool's `labels` section indicates that the
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corresponding label is available for use in this pool.
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.. code-block:: yaml
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labels:
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- name: small-node
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backing-label: large-node
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max-parallel-jobs: 2
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grace-time: 600
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Each entry is a dictionary with the following keys:
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.. attr:: name
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:type: str
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:required:
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Identifier for this label.
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.. attr:: backing-label
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:type: str
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:required:
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Refers to the name of a different label in Nodepool which
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will be used to supply the backing nodes for requests of
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this label.
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.. attr:: max-parallel-jobs
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:type: int
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:default: 1
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The number of jobs that can run in parallel on a single
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backing node.
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.. attr:: grace-time
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:type: int
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:default: 60
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When all requested nodes which were assigned to a backing
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node have been deleted, the backing node itself is
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eligible for deletion. In order to reduce churn,
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NodePool will wait a certain amount of time after the
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last requested node is deleted to see if new requests
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arrive for this label before deleting the backing node.
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Set this value to the amount of time in seconds to wait.
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