Merge pull request #15360 from clintongormley/improve_network_docs

Improve network docs
This commit is contained in:
Clinton Gormley 2015-12-10 12:02:05 +01:00
commit 588203e72b
5 changed files with 170 additions and 76 deletions

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@ -137,8 +137,7 @@ public class NetworkService extends AbstractComponent {
* Resolves {@code publishHosts} to a single publish address. The fact that it returns * Resolves {@code publishHosts} to a single publish address. The fact that it returns
* only one address is just a current limitation. * only one address is just a current limitation.
* <p> * <p>
* If {@code publishHosts} resolves to more than one address, <b>then one is selected with magic</b>, * If {@code publishHosts} resolves to more than one address, <b>then one is selected with magic</b>
* and the user is warned (they can always just be more specific).
* @param publishHosts list of hosts to publish as. this may contain special pseudo-hostnames * @param publishHosts list of hosts to publish as. this may contain special pseudo-hostnames
* such as _local_ (see the documentation). if it is null, it will be populated * such as _local_ (see the documentation). if it is null, it will be populated
* based on global default settings. * based on global default settings.
@ -186,13 +185,12 @@ public class NetworkService extends AbstractComponent {
} }
} }
// 3. warn user if we end out with multiple publish addresses // 3. if we end out with multiple publish addresses, select by preference.
// don't warn the user, or they will get confused by bind_host vs publish_host etc.
if (addresses.length > 1) { if (addresses.length > 1) {
List<InetAddress> sorted = new ArrayList<>(Arrays.asList(addresses)); List<InetAddress> sorted = new ArrayList<>(Arrays.asList(addresses));
NetworkUtils.sortAddresses(sorted); NetworkUtils.sortAddresses(sorted);
addresses = new InetAddress[] { sorted.get(0) }; addresses = new InetAddress[] { sorted.get(0) };
logger.warn("publish host: {} resolves to multiple addresses, auto-selecting {{}} as single publish address",
Arrays.toString(publishHosts), NetworkAddress.format(addresses[0]));
} }
return addresses[0]; return addresses[0];
} }

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@ -60,19 +60,8 @@
# For more information, see the documentation at: # For more information, see the documentation at:
# <http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-network.html> # <http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-network.html>
# #
# ---------------------------------- Gateway -----------------------------------
#
# Block initial recovery after a full cluster restart until N nodes are started:
#
# gateway.recover_after_nodes: 3
#
# For more information, see the documentation at:
# <http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-gateway.html>
#
# --------------------------------- Discovery ---------------------------------- # --------------------------------- Discovery ----------------------------------
# #
# Elasticsearch nodes will find each other via unicast, by default.
#
# Pass an initial list of hosts to perform discovery when new node is started: # Pass an initial list of hosts to perform discovery when new node is started:
# The default list of hosts is ["127.0.0.1", "[::1]"] # The default list of hosts is ["127.0.0.1", "[::1]"]
# #
@ -85,6 +74,15 @@
# For more information, see the documentation at: # For more information, see the documentation at:
# <http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-discovery.html> # <http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-discovery.html>
# #
# ---------------------------------- Gateway -----------------------------------
#
# Block initial recovery after a full cluster restart until N nodes are started:
#
# gateway.recover_after_nodes: 3
#
# For more information, see the documentation at:
# <http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-gateway.html>
#
# ---------------------------------- Various ----------------------------------- # ---------------------------------- Various -----------------------------------
# #
# Disable starting multiple nodes on a single system: # Disable starting multiple nodes on a single system:

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@ -360,6 +360,22 @@ are:
`s`:: Second `s`:: Second
`ms`:: Milli-second `ms`:: Milli-second
[[size-units]]
[float]
=== Data size units
Whenever the size of data needs to be specified, eg when setting a buffer size
parameter, the value must specify the unit, like `10kb` for 10 kilobytes. The
supported units are:
[horizontal]
`b`:: Bytes
`kb`:: Kilobytes
`mb`:: Megabytes
`gb`:: Gigabytes
`tb`:: Terabytes
`pb`:: Petabytes
[[distance-units]] [[distance-units]]
[float] [float]
=== Distance Units === Distance Units

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@ -7,6 +7,7 @@
:jdk: 1.8.0_25 :jdk: 1.8.0_25
:defguide: https://www.elastic.co/guide/en/elasticsearch/guide/current :defguide: https://www.elastic.co/guide/en/elasticsearch/guide/current
:plugins: https://www.elastic.co/guide/en/elasticsearch/plugins/master :plugins: https://www.elastic.co/guide/en/elasticsearch/plugins/master
:javaclient: https://www.elastic.co/guide/en/elasticsearch/client/java-api/master/
:issue: https://github.com/elastic/elasticsearch/issues/ :issue: https://github.com/elastic/elasticsearch/issues/
:pull: https://github.com/elastic/elasticsearch/pull/ :pull: https://github.com/elastic/elasticsearch/pull/

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@ -1,94 +1,175 @@
[[modules-network]] [[modules-network]]
== Network Settings == Network Settings
There are several modules within a Node that use network based Elasticsearch binds to localhost only by default. This is sufficient for you
configuration, for example, the to run a local development server (or even a development cluster, if you start
<<modules-transport,transport>> and multiple nodes on the same machine), but you will need to configure some
<<modules-http,http>> modules. Node level <<common-network-settings,basic network settings>> in order to run a real
network settings allows to set common settings that will be shared among production cluster across multiple servers.
all network based modules (unless explicitly overridden in each module).
Be careful with host configuration! Never expose an unprotected instance [WARNING]
to the public internet. .Be careful with the network configuration!
=============================
Never expose an unprotected node to the public internet.
=============================
The `network.bind_host` setting allows to control the host different network [float]
components will bind on. By default, the bind host will be `_local_` [[common-network-settings]]
(loopback addresses such as `127.0.0.1`, `::1`). === Commonly Used Network Settings
The `network.publish_host` setting allows to control the host the node will `network.host`::
publish itself within the cluster so other nodes will be able to connect to it.
Currently an elasticsearch node may be bound to multiple addresses, but only
publishes one. If not specified, this defaults to the "best" address from
`network.bind_host`, sorted by IPv4/IPv6 stack preference, then by reachability.
The `network.host` setting is a simple setting to automatically set both The node will bind to this hostname or IP address and _publish_ (advertise)
`network.bind_host` and `network.publish_host` to the same host value. this host to other nodes in the cluster. Accepts an IP address, hostname, or a
<<network-interface-values,special value>>.
+
Defaults to `_local_`.
Both settings allows to be configured with either explicit host address(es) `discovery.zen.ping.unicast.hosts`::
or host name(s). The settings also accept logical setting value(s) explained
in the following table:
[cols="<,<",options="header",] In order to join a cluster, a node needs to know the hostname or IP address of
|======================================================================= at least some of the other nodes in the cluster. This settting provides the
|Logical Host Setting Value |Description initial list of other nodes that this node will try to contact. Accepts IP
|`_local_` |Will be resolved to loopback addresses addresses or hostnames.
+
Defaults to `["127.0.0.1", "[::1]"]`.
|`_local:ipv4_` |Will be resolved to loopback IPv4 addresses (e.g. 127.0.0.1) `http.port`::
|`_local:ipv6_` |Will be resolved to loopback IPv6 addresses (e.g. ::1) Port to bind to for incoming HTTP requests. Accepts a single value or a range.
If a range is specified, the node will bind to the first available port in the
range.
+
Defaults to `9200-9300`.
|`_site_` |Will be resolved to site-local addresses ("private network") `transport.tcp.port`::
|`_site:ipv4_` |Will be resolved to site-local IPv4 addresses (e.g. 192.168.0.1) Port to bind for communication between nodes. Accepts a single value or a
range. If a range is specified, the node will bind to the first available port
in the range.
+
Defaults to `9300-9400`.
|`_site:ipv6_` |Will be resolved to site-local IPv6 addresses (e.g. fec0::1) [float]
[[network-interface-values]]
=== Special values for `network.host`
|`_global_` |Will be resolved to globally-scoped addresses ("publicly reachable") The following special values may be passed to `network.host`:
|`_global:ipv4_` |Will be resolved to globally-scoped IPv4 addresses (e.g. 8.8.8.8) [horizontal]
`_[networkInterface]_`::
|`_global:ipv6_` |Will be resolved to globally-scoped IPv6 addresses (e.g. 2001:4860:4860::8888) Addresses of a network interface, for example `_en0_`.
|`_[networkInterface]_` |Resolves to the addresses of the provided `_local_`::
network interface. For example `_en0_`.
|`_[networkInterface]:ipv4_` |Resolves to the ipv4 addresses of the Any loopback addresses on the system, for example `127.0.0.1`.
provided network interface. For example `_en0:ipv4_`.
|`_[networkInterface]:ipv6_` |Resolves to the ipv6 addresses of the `_site_`::
provided network interface. For example `_en0:ipv6_`.
|=======================================================================
When the `discovery-ec2` plugin is installed, you can use Any site-local addresses on the system, for example `192.168.0.1`.
{plugins}/discovery-ec2-discovery.html#discovery-ec2-network-host[ec2 specific host settings].
When the `discovery-gce` plugin is installed, you can use `_global_`::
{plugins}/discovery-gce-network-host.html[gce specific host settings].
Any globally-scoped addresses on the system, for example `8.8.8.8`.
[float]
==== IPv4 vs IPv6
These special values will work over both IPv4 and IPv6 by default, but you can
also limit this with the use of `:ipv4` of `:ipv6` specifiers. For example,
`_en0:ipv4_` would only bind to the IPv4 addresses of interface `en0`.
[TIP]
.Discovery in the cloud
================================
More special settings are available when running in the cloud with either the
{plugins}/discovery-ec2-discovery.html#discovery-ec2-network-host[EC2 discovery plugin] or the
{plugins}/discovery-gce-network-host.html#discovery-gce-network-host[Google Compute Engine discovery plugin]
installed.
================================
[float]
[[advanced-network-settings]]
=== Advanced network settings
The `network.host` setting explained in <<common-network-settings,Commonly used network settings>>
is a shortcut which sets the _bind host_ and the _publish host_ at the same
time. In advanced used cases, such as when running behind a proxy server, you
may need to set these settings to different values:
`network.bind_host`::
This specifies which network interface(s) a node should bind to in order to
listen for incoming requests. A node can bind to multiple interfaces, e.g.
two network cards, or a site-local address and a local address. Defaults to
`network.host`.
`network.publish_host`::
The publish host is the single interface that the node advertises to other
nodes in the cluster, so that those nodes can connect to it. Currently an
elasticsearch node may be bound to multiple addresses, but only publishes one.
If not specified, this defaults to the ``best'' address from
`network.bind_host`, sorted by IPv4/IPv6 stack preference, then by
reachability.
Both of the above settings can be configured just like `network.host` -- they
accept IP addresses, host names, and
<<network-interface-values,special values>>.
[float] [float]
[[tcp-settings]] [[tcp-settings]]
=== TCP Settings === Advanced TCP Settings
Any component that uses TCP (like the HTTP, Transport and Memcached) Any component that uses TCP (like the <<modules-http,HTTP>> and
share the following allowed settings: <<modules-transport,Transport>> modules) share the following settings:
[cols="<,<",options="header",] [horizontal]
|======================================================================= `network.tcp.no_delay`::
|Setting |Description
|`network.tcp.no_delay` |Enable or disable tcp no delay setting. Enable or disable the https://en.wikipedia.org/wiki/Nagle%27s_algorithm[TCP no delay]
setting. Defaults to `true`.
`network.tcp.keep_alive`::
Enable or disable https://en.wikipedia.org/wiki/Keepalive[TCP keep alive].
Defaults to `true`. Defaults to `true`.
|`network.tcp.keep_alive` |Enable or disable tcp keep alive. Defaults `network.tcp.reuse_address`::
to `true`.
|`network.tcp.reuse_address` |Should an address be reused or not. Should an address be reused or not. Defaults to `true` on non-windows
Defaults to `true` on non-windows machines. machines.
|`network.tcp.send_buffer_size` |The size of the tcp send buffer size `network.tcp.send_buffer_size`::
(in size setting format). By default not explicitly set.
|`network.tcp.receive_buffer_size` |The size of the tcp receive buffer The size of the TCP send buffer (specified with <<size-units,size units>>).
size (in size setting format). By default not explicitly set. By default not explicitly set.
|=======================================================================
`network.tcp.receive_buffer_size`::
The size of the TCP receive buffer (specified with <<size-units,size units>>).
By default not explicitly set.
[float]
=== Transport and HTTP protocols
An Elasticsearch node exposes two network protocols which inherit the above
settings, but may be further configured independently:
TCP Transport::
Used for communication between nodes in the cluster and by the Java
{javaclient}/node-client.html[Node client],
{javaclient}/transport-client.html[Transport client], and by the
<<modules-tribe,Tribe node>>. See the <<modules-transport,Transport module>>
for more information.
HTTP::
Exposes the JSON-over-HTTP interface used by all clients other than the Java
clients. See the <<modules-http,HTTP module>> for more information.