mirror of
https://github.com/itzg/docker-minecraft-server.git
synced 2026-05-13 23:45:25 +00:00
Geoff Bourne
199 lines
6.4 KiB
Markdown
Executable File
199 lines
6.4 KiB
Markdown
Executable File
This Docker image provides an easily configurable Elasticsearch node. Via
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port mappings, it is easy to create an arbitrarily sized cluster of
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nodes. As long as the versions match, you can mix-and-match "real"
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Elasticsearch nodes with container-ized ones.
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# Basic Usage
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To start an Elasticsearch data node that listens on the standard ports on
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your host's network interface:
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docker run -d -p 9200:9200 -p 9300:9300 itzg/elasticsearch
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You'll then be able to connect to the Elasticsearch HTTP interface to confirm
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it's alive:
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http://DOCKERHOST:9200/
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{
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"status" : 200,
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"name" : "Charon",
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"version" : {
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"number" : "1.3.5",
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"build_hash" : "4a50e7df768fddd572f48830ae9c35e4ded86ac1",
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"build_timestamp" : "2014-11-05T15:21:28Z",
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"build_snapshot" : false,
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"lucene_version" : "4.9"
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},
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"tagline" : "You Know, for Search"
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}
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Where `DOCKERHOST` would be the actual hostname of your host running
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Docker.
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# Simple, multi-node cluster
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To run a multi-node cluster (3-node in this example) on a single Docker machine use:
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docker run -d --name es0 -p 9200:9200 es
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docker run -d --name es1 --link es0 -e UNICAST_HOSTS=es0 es
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docker run -d --name es2 --link es0 -e UNICAST_HOSTS=es0 es
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and then check the cluster health, such as http://192.168.99.100:9200/_cluster/health?pretty
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{
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"cluster_name" : "elasticsearch",
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"status" : "green",
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"timed_out" : false,
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"number_of_nodes" : 3,
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"number_of_data_nodes" : 3,
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"active_primary_shards" : 0,
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"active_shards" : 0,
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"relocating_shards" : 0,
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"initializing_shards" : 0,
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"unassigned_shards" : 0
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}
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# Configuration
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The following configuration options are specified using `docker run`
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environment variables (`-e`) like
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docker run ... -e NAME=VALUE ... itzg/elasticsearch
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Since Docker's `-e` settings are baked into the container definition, this image provides an
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extra feature to change any of the settings below for an existing container. Either
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create/edit the file `env` in the `/conf` volume mapping or edit within the running container's
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context using:
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docker exec -it CONTAINER_ID vi /conf/env
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replacing `CONTAINER_ID` with the container's ID or name.
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The contents of the `/conf/env` file are standard shell
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NAME=VALUE
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entries where `NAME` is one of the variables described below.
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Configuration options not explicitly supported below can be specified via the `OPTS` environment variable. For
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example, by default `OPTS` is set with
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OPTS=-Dnetwork.bind_host=_non_loopback_
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_NOTE: That option is a default since `bind_host` defaults to `localhost` as of 2.0, which isn't helpful for
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port mapping out from the container_.
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## Cluster Name
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If joining a pre-existing cluster, then you may need to specify a cluster name
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different than the default "elasticsearch":
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-e CLUSTER=dockers
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## Zen Unicast Hosts
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When joining a multi-physical-host cluster, multicast may not be supported
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on the physical network. In that case, your node can reference specific one or more hosts in
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the cluster via the
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[Zen Unicast Hosts](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/modules-discovery-zen.html#unicast) capability as a comma-separated list of `HOST:PORT` pairs:
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-e UNICAST_HOSTS=HOST:PORT[,HOST:PORT]
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such as
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-e UNICAST_HOSTS=192.168.0.100:9300
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## Plugins
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You can install one or more plugins before startup by passing a comma-separated
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list of plugins.
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-e PLUGINS=ID[,ID]
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In this example, it will install the Marvel plugin
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-e PLUGINS=elasticsearch/marvel/latest
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Many more plugins [are available here](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/modules-plugins.html#known-plugins).
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## Publish As
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Since the container gives the Elasticsearch software an isolated perspective
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of its networking, it will most likely advertise its published address with
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a container-internal IP address. This can be overridden with a physical networking
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name and port using:
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-e PUBLISH_AS=DOCKERHOST:9301
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_Author Note: I have yet to hit a case where this was actually necessary. Other
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than the cosmetic weirdness in the logs, Elasticsearch seems to be quite tolerant._
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## Node Name
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Rather than use the randomly assigned node name, you can indicate a specific
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one using:
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-e NODE_NAME=Docker
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## Node Type
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If you refer to [the Node section](https://www.elastic.co/guide/en/elasticsearch/reference/2.3/modules-node.html)
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of the Elasticsearch reference guide, you'll find that there's three main types of nodes master-eligible, data, and client.
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In larger clusters it is important to dedicate a small number (but minimum of 3) of master nodes.
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There are also cases where a large cluster may need dedicated gateway nodes that are neither
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master nor data nodes and purely operate as "smart routers" and have large amounts of CPU and
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memory to handle search-reduce.
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To simplify all that, this image provides a `TYPE` variable to pick amongst these combinations. The
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choices are:
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* (default) : the default node type which is both master-eligible and a data node
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* `MASTER` : master-eligible, but holds no data. It is good to have three or more of these in a
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large cluster
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* `DATA` (or `NON_MASTER`) : holds data and serves search/index requests. Scale these out for elastic-y goodness.
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* `GATEWAY` : only operates as a client node or a "smart router". These are the ones whose HTTP port 9200 will need to be exposed
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A [Docker Compose](https://docs.docker.com/compose/overview/)
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file will serve as a good example of these three node types:
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```
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version: '2'
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services:
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gateway:
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image: itzg/elasticsearch
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environment:
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UNICAST_HOSTS: master
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TYPE: GATEWAY
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ports:
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- "9200:9200"
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master:
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image: itzg/elasticsearch
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environment:
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UNICAST_HOSTS: gateway
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TYPE: MASTER
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MIN_MASTERS: 2
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data:
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image: itzg/elasticsearch
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environment:
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UNICAST_HOSTS: master,gateway
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TYPE: DATA
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```
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## Minimum Master Nodes
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In combination with the `TYPE` variable above, you will also want to configure the minimum
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master nodes to [avoid split-brain](https://www.elastic.co/guide/en/elasticsearch/reference/2.3/modules-node.html#split-brain)
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during network outages.
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The minimum, which is can be calculated as `(master_eligible_nodes / 2) + 1`, can be set with the `MIN_MASTERS` variable.
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Using the Docker Compose file above, a value of 2 is appropriate when scaling the cluster to
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3 master nodes:
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docker-compose scale master=3
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