2019-06-24 14:23:44 +00:00
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========
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Glossary
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========
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.. glossary::
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Availability Zone
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Availability zones are a logical subdivision of cloud block storage,
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compute and network services. They provide a way for cloud operators to
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logically segment their compute based on arbitrary factors like
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location (country, datacenter, rack), network layout and/or power
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source.
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For more information, refer to :doc:`/admin/aggregates`.
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2019-12-13 19:54:18 +00:00
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Boot From Volume
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A server that is created with a
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:doc:`Block Device Mapping </user/block-device-mapping>` with
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``boot_index=0`` and ``destination_type=volume``. The root volume can
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already exist when the server is created or be created by the compute
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service as part of the server creation. Note that a server can have
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volumes attached and not be boot-from-volume. A boot from volume server
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has an empty ("") ``image`` parameter in ``GET /servers/{server_id}``
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responses.
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2022-02-01 18:28:48 +00:00
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Cell
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A cell is a shard or horizontal partition in a nova deployment.
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A cell mostly consists of a database, queue, and set of compute nodes.
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All deployments willl have at least one cell (and one "fake" cell).
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Larger deployments can have many.
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For more information, refer to :doc:`/admin/cells`.
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2019-12-16 17:50:07 +00:00
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Cross-Cell Resize
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A resize (or cold migrate) operation where the source and destination
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compute hosts are mapped to different cells. By default, resize and
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cold migrate operations occur within the same cell.
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For more information, refer to
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:doc:`/admin/configuration/cross-cell-resize`.
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2019-06-24 14:23:44 +00:00
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Host Aggregate
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Host aggregates can be regarded as a mechanism to further partition an
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2020-04-12 04:01:24 +00:00
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:term:`Availability Zone`; while availability zones are visible to
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2019-06-24 14:23:44 +00:00
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users, host aggregates are only visible to administrators. Host
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aggregates provide a mechanism to allow administrators to assign
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key-value pairs to groups of machines. Each node can have multiple
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aggregates, each aggregate can have multiple key-value pairs, and the
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same key-value pair can be assigned to multiple aggregates.
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For more information, refer to :doc:`/admin/aggregates`.
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2019-12-16 17:50:07 +00:00
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Same-Cell Resize
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A resize (or cold migrate) operation where the source and destination
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compute hosts are mapped to the same cell. Also commonly referred to
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as "standard resize" or simply "resize". By default, resize and
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cold migrate operations occur within the same cell.
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For more information, refer to
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:doc:`/contributor/resize-and-cold-migrate`.
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