135 lines
5.6 KiB
Plaintext
135 lines
5.6 KiB
Plaintext
[[modules-transport]]
|
|
== Transport
|
|
|
|
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
|
|
http://en.wikipedia.org/wiki/C10k_problem[C10k problem], as well as
|
|
being the ideal solution for scatter (broadcast) / gather operations such
|
|
as search in Elasticsearch.
|
|
|
|
[float]
|
|
=== TCP Transport
|
|
|
|
The TCP transport is an implementation of the transport module using
|
|
TCP. It allows for the following settings:
|
|
|
|
[cols="<,<",options="header",]
|
|
|=======================================================================
|
|
|Setting |Description
|
|
|`transport.tcp.port` |A bind port range. Defaults to `9300-9400`.
|
|
|
|
|`transport.publish_port` |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 `transport.tcp.port` is not directly
|
|
addressable from the outside. Defaults to the actual port assigned via
|
|
`transport.tcp.port`.
|
|
|
|
|`transport.bind_host` |The host address to bind the transport service to. Defaults to `transport.host` (if set) or `network.bind_host`.
|
|
|
|
|`transport.publish_host` |The host address to publish for nodes in the cluster to connect to. Defaults to `transport.host` (if set) or `network.publish_host`.
|
|
|
|
|`transport.host` |Used to set the `transport.bind_host` and the `transport.publish_host` Defaults to `transport.host` or `network.host`.
|
|
|
|
|
|
|`transport.tcp.connect_timeout` |The socket connect timeout setting (in
|
|
time setting format). Defaults to `30s`.
|
|
|
|
|`transport.tcp.compress` |Set to `true` to enable compression (`DEFLATE`)
|
|
between all nodes. Defaults to `false`.
|
|
|
|
|`transport.ping_schedule` | Schedule a regular application-level ping message
|
|
to ensure that transport connections between nodes are kept alive. Defaults to
|
|
`5s` in the transport client and `-1` (disabled) elsewhere. It is preferable to
|
|
correctly configure TCP keep-alives instead of using this feature, because TCP
|
|
keep-alives apply to all kinds of long-lived connection and not just to
|
|
transport connections.
|
|
|
|
|=======================================================================
|
|
|
|
It also uses the common
|
|
<<modules-network,network settings>>.
|
|
|
|
[float]
|
|
==== TCP Transport Profiles
|
|
|
|
Elasticsearch allows you to bind to multiple ports on different interfaces by the use of transport profiles. See this example configuration
|
|
|
|
[source,yaml]
|
|
--------------
|
|
transport.profiles.default.port: 9300-9400
|
|
transport.profiles.default.bind_host: 10.0.0.1
|
|
transport.profiles.client.port: 9500-9600
|
|
transport.profiles.client.bind_host: 192.168.0.1
|
|
transport.profiles.dmz.port: 9700-9800
|
|
transport.profiles.dmz.bind_host: 172.16.1.2
|
|
--------------
|
|
|
|
The `default` profile is a special. It is used as fallback for any other profiles, if those do not have a specific configuration setting set.
|
|
Note that the default profile is how other nodes in the cluster will connect to this node usually. In the future this feature will allow to enable node-to-node communication via multiple interfaces.
|
|
|
|
The following parameters can be configured like that
|
|
|
|
* `port`: The port to bind to
|
|
* `bind_host`: The host to bind
|
|
* `publish_host`: The host which is published in informational APIs
|
|
* `tcp_no_delay`: Configures the `TCP_NO_DELAY` option for this socket
|
|
* `tcp_keep_alive`: Configures the `SO_KEEPALIVE` option for this socket
|
|
* `reuse_address`: Configures the `SO_REUSEADDR` option for this socket
|
|
* `tcp_send_buffer_size`: Configures the send buffer size of the socket
|
|
* `tcp_receive_buffer_size`: Configures the receive buffer size of the socket
|
|
|
|
[float]
|
|
==== Long-lived idle connections
|
|
|
|
Elasticsearch opens a number of long-lived TCP connections between each pair of
|
|
nodes in the cluster, and some of these connections may be idle for an extended
|
|
period of time. Nonetheless, Elasticsearch requires these connections to remain
|
|
open, and it can disrupt the operation of the cluster if any inter-node
|
|
connections are closed by an external influence such as a firewall. It is
|
|
important to configure your network to preserve long-lived idle connections
|
|
between Elasticsearch nodes, for instance by leaving `tcp_keep_alive` enabled
|
|
and ensuring that the keepalive interval is shorter than any timeout that might
|
|
cause idle connections to be closed, or by setting `transport.ping_schedule` if
|
|
keepalives cannot be configured.
|
|
|
|
[float]
|
|
=== Transport Tracer
|
|
|
|
The transport module has a dedicated tracer logger which, when activated, logs incoming and out going requests. The log can be dynamically activated
|
|
by settings the level of the `org.elasticsearch.transport.TransportService.tracer` logger to `TRACE`:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
PUT _cluster/settings
|
|
{
|
|
"transient" : {
|
|
"logger.org.elasticsearch.transport.TransportService.tracer" : "TRACE"
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
|
|
You can also control which actions will be traced, using a set of include and exclude wildcard patterns. By default every request will be traced
|
|
except for fault detection pings:
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
PUT _cluster/settings
|
|
{
|
|
"transient" : {
|
|
"transport.tracer.include" : "*",
|
|
"transport.tracer.exclude" : "internal:discovery/zen/fd*"
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
|
|
|