130 lines
4.0 KiB
ReStructuredText
130 lines
4.0 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:: 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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