The transport module is used for internal communication between nodes within the cluster. Each call that goes from one node to the other uses the transport module (for example, when an HTTP GET request is processed by one node, and should actually be processed by another node that holds the data).
The transport mechanism is completely asynchronous in nature, meaning that there is no blocking thread waiting for a response. The benefit of using asynchronous communication is first solving the C10k problem, as well as being the ideal solution for scatter (broadcast) / gather operations such as search in ElasticSearch.
The TCP transport is an implementation of the transport module using TCP. It allows for the following settings:
A bind port range. Defaults to
The port that other nodes in the cluster
should use when communicating with this node. Useful when a cluster node
is behind a proxy or firewall and the
The host address to bind the transport service to. Defaults to
The host address to publish for nodes in the cluster to connect to. Defaults to
Used to set the
The socket connect timeout setting (in
time setting format). Defaults to
It also uses the common network settings.
This is a handy transport to use when running integration tests within
the JVM. It is automatically enabled when using