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Diffstat (limited to 'docs/reference/modules/node.asciidoc')
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diff --git a/docs/reference/modules/node.asciidoc b/docs/reference/modules/node.asciidoc new file mode 100644 index 0000000..5e40522 --- /dev/null +++ b/docs/reference/modules/node.asciidoc @@ -0,0 +1,32 @@ +[[modules-node]] +== Node + +*elasticsearch* allows to configure a node to either be allowed to store +data locally or not. Storing data locally basically means that shards of +different indices are allowed to be allocated on that node. By default, +each node is considered to be a data node, and it can be turned off by +setting `node.data` to `false`. + +This is a powerful setting allowing to simply create smart load +balancers that take part in some of different API processing. Lets take +an example: + +We can start a whole cluster of data nodes which do not even start an +HTTP transport by setting `http.enabled` to `false`. Such nodes will +communicate with one another using the +<<modules-transport,transport>> module. In front +of the cluster we can start one or more "non data" nodes which will +start with HTTP enabled. All HTTP communication will be performed +through these "non data" nodes. + +The benefit of using that is first the ability to create smart load +balancers. These "non data" nodes are still part of the cluster, and +they redirect operations exactly to the node that holds the relevant +data. The other benefit is the fact that for scatter / gather based +operations (such as search), these nodes will take part of the +processing since they will start the scatter process, and perform the +actual gather processing. + +This relieves the data nodes to do the heavy duty of indexing and +searching, without needing to process HTTP requests (parsing), overload +the network, or perform the gather processing. |