74 lines
2.5 KiB
Plaintext
74 lines
2.5 KiB
Plaintext
[[modules-tribe]]
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== Tribe node
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The _tribes_ feature allows a _tribe node_ to act as a federated client across
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multiple clusters.
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The tribe node works by retrieving the cluster state from all connected
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clusters and merging them into a global cluster state. With this information
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at hand, it is able to perform read and write operations against the nodes in
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all clusters as if they were local.
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The `elasticsearch.yml` config file for a tribe node just needs to list the
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clusters that should be joined, for instance:
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[source,yaml]
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--------------------------------
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tribe:
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t1: <1>
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cluster.name: cluster_one
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t2: <1>
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cluster.name: cluster_two
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--------------------------------
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<1> `t1` and `t2` are arbitrary names representing the connection to each
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cluster.
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The example above configures connections to two clusters, name `t1` and `t2`
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respectively. The tribe node will create a <<modules-node,node client>> to
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connect each cluster using <<unicast,unicast discovery>> by default. Any
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other settings for the connection can be configured under `tribe.{name}`, just
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like the `cluster.name` in the example.
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The merged global cluster state means that almost all operations work in the
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same way as a single cluster: distributed search, suggest, percolation,
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indexing, etc.
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However, there are a few exceptions:
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* The merged view cannot handle indices with the same name in multiple
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clusters. By default it will pick one of them, see later for on_conflict options.
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* Master level read operations (eg <<cluster-state>>, <<cluster-health>>)
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will automatically execute with a local flag set to true since there is
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no master.
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* Master level write operations (eg <<indices-create-index>>) are not
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allowed. These should be performed on a single cluster.
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The tribe node can be configured to block all write operations and all
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metadata operations with:
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[source,yaml]
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--------------------------------
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tribe:
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blocks:
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write: true
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metadata: true
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--------------------------------
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The tribe node can also configure blocks on selected indices:
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[source,yaml]
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--------------------------------
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tribe:
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blocks:
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write.indices: hk*,ldn*
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metadata.indices: hk*,ldn*
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--------------------------------
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When there is a conflict and multiple clusters hold the same index, by default
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the tribe node will pick one of them. This can be configured using the `tribe.on_conflict`
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setting. It defaults to `any`, but can be set to `drop` (drop indices that have
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a conflict), or `prefer_[tribeName]` to prefer the index from a specific tribe.
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