mirror of https://github.com/ceph/ceph
101 lines
3.4 KiB
ReStructuredText
101 lines
3.4 KiB
ReStructuredText
============
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Sync Modules
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============
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.. versionadded:: Kraken
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The `Multisite`_ functionality of RGW introduced in Jewel allowed the ability to
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create multiple zones and mirror data and metadata between them. ``Sync Modules``
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are built atop of the multisite framework that allows for forwarding data and
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metadata to a different external tier. A sync module allows for a set of actions
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to be performed whenever a change in data occurs (metadata ops like bucket or
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user creation etc. are also regarded as changes in data). As the rgw multisite
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changes are eventually consistent at remote sites, changes are propagated
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asynchronously. This would allow for unlocking use cases such as backing up the
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object storage to an external cloud cluster or a custom backup solution using
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tape drives, indexing metadata in ElasticSearch etc.
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A sync module configuration is local to a zone. The sync module determines
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whether the zone exports data or can only consume data that was modified in
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another zone. As of luminous the supported sync plugins are `elasticsearch`_,
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``rgw``, which is the default sync plugin that synchronises data between the
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zones and ``log`` which is a trivial sync plugin that logs the metadata
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operation that happens in the remote zones. The following docs are written with
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the example of a zone using `elasticsearch sync module`_, the process would be similar
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for configuring any sync plugin
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.. toctree::
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:maxdepth: 1
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ElasticSearch Sync Module <elastic-sync-module>
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Cloud Sync Module <cloud-sync-module>
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PubSub Module <pubsub-module>
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Archive Sync Module <archive-sync-module>
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.. note ``rgw`` is the default sync plugin and there is no need to explicitly
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configure this
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Requirements and Assumptions
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----------------------------
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Let us assume a simple multisite configuration as described in the `Multisite`_
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docs, of 2 zones ``us-east`` and ``us-west``, let's add a third zone
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``us-east-es`` which is a zone that only processes metadata from the other
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sites. This zone can be in the same or a different ceph cluster as ``us-east``.
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This zone would only consume metadata from other zones and RGWs in this zone
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will not serve any end user requests directly.
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Configuring Sync Modules
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------------------------
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Create the third zone similar to the `Multisite`_ docs, for example
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::
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# radosgw-admin zone create --rgw-zonegroup=us --rgw-zone=us-east-es \
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--access-key={system-key} --secret={secret} --endpoints=http://rgw-es:80
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A sync module can be configured for this zone via the following
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::
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# radosgw-admin zone modify --rgw-zone={zone-name} --tier-type={tier-type} --tier-config={set of key=value pairs}
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For example in the ``elasticsearch`` sync module
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::
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# radosgw-admin zone modify --rgw-zone={zone-name} --tier-type=elasticsearch \
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--tier-config=endpoint=http://localhost:9200,num_shards=10,num_replicas=1
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For the various supported tier-config options refer to the `elasticsearch sync module`_ docs
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Finally update the period
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::
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# radosgw-admin period update --commit
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Now start the radosgw in the zone
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::
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# systemctl start ceph-radosgw@rgw.`hostname -s`
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# systemctl enable ceph-radosgw@rgw.`hostname -s`
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.. _`Multisite`: ../multisite
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.. _`elasticsearch sync module`: ../elastic-sync-module
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.. _`elasticsearch`: ../elastic-sync-module
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.. _`cloud sync module`: ../cloud-sync-module
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.. _`pubsub module`: ../pubsub-module
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.. _`archive sync module`: ../archive-sync-module
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