ElasticSearch系列（三） 集群搭建

本文，讲述下集群的整体搭建。

篇幅很短，主要基于前面的文章所写：

集群规模：两台机器，配置基本完全一样。

机器A：

JDK版本：1.8.0_111

操作系统版本：Linux version 2.6.32-504.el6.x86_64 (mockbuild@c6b9.bsys.dev.centos.org) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-11) (GCC) ) #1 SMP Wed Oct 15 04:27:16 UTC 2014

这里：想要查看操作系统版本，可以通过cat /proc/version 命令查看，可能linux不同版本的操作系统文件不同

机器B：

JDK版本：1.8.0_111；这说明，只要都是JDK 1.8即可，具体更新版本不重要。

操作系统版本：Linux version 2.6.32-504.el6.x86_64 (mockbuild@c6b9.bsys.dev.centos.org) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-11) (GCC) ) #1 SMP Wed Oct 15 04:27:16 UTC 2014

对于ElasticSearch来说，最重要的其实就是elasticsearch.yml文件，下面附上两台机器的配置文件。

机器A：作为master节点，数据节点

# ======================== Elasticsearch Configuration =========================
# ---------------------------------- Cluster -----------------------------------
#
# Use a descriptive name for your cluster:
#
cluster.name: elasticsearch
#
# ------------------------------------ Node ------------------------------------
#
# Use a descriptive name for the node:
#
node.name: node-1
node.master: true
node.data: true
#
# Add custom attributes to the node:
#
#node.attr.rack: r1
#
# ----------------------------------- Paths ------------------------------------
#
# Path to directory where to store the data (separate multiple locations by comma):
#
#path.data: /path/to/data
#
# Path to log files:
#
#path.logs: /path/to/logs
#
# ----------------------------------- Memory -----------------------------------
#
# Lock the memory on startup:
#
bootstrap.memory_lock: false
bootstrap.system_call_filter: false
#
# Make sure that the heap size is set to about half the memory available
# on the system and that the owner of the process is allowed to use this
# limit.
#
# Elasticsearch performs poorly when the system is swapping the memory.
#
# ---------------------------------- Network -----------------------------------
#
# Set the bind address to a specific IP (IPv4 or IPv6):
#
network.host: 192.168.100.34
#http.host: 192.168.100.34
#
# Set a custom port for HTTP:
#
http.port: 9200
#
# For more information, consult the network module documentation.
#
# --------------------------------- Discovery ----------------------------------
#
# 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]"]
#
discovery.zen.ping.unicast.hosts: ["192.168.100.34", "192.168.100.35","192.168.100.112"]
#
# Prevent the "split brain" by configuring the majority of nodes (total number of master-eligible nodes / 2 + 1):
#
discovery.zen.minimum_master_nodes: 2
#
# For more information, consult the zen discovery module documentation.
#
# ---------------------------------- Gateway -----------------------------------
#
# Block initial recovery after a full cluster restart until N nodes are started:
#
#gateway.recover_after_nodes: 3
#
# For more information, consult the gateway module documentation.
#
# ---------------------------------- Various -----------------------------------
#
# Require explicit names when deleting indices:
#
#action.destructive_requires_name: true

机器B：主节点，数据节点

# ======================== Elasticsearch Configuration =========================
# ---------------------------------- Cluster -----------------------------------
#
# Use a descriptive name for your cluster:
#
cluster.name: elasticsearch
#
# ------------------------------------ Node ------------------------------------
#
# Use a descriptive name for the node:
#节点在集群中的名称
node.name: node-2
#是否是master节点
node.master: true
#是否是数据节点
node.data: true
#
# Add custom attributes to the node:
#
#node.attr.rack: r1
#
# ----------------------------------- Paths ------------------------------------
#
# Path to directory where to store the data (separate multiple locations by comma):
#数据存储路径
#path.data: /path/to/data
#日志存储路径
#这两个都是默认的，不用修改就行
# Path to log files:
#
#path.logs: /path/to/logs
#
# ----------------------------------- Memory -----------------------------------
#
# Lock the memory on startup:
#
bootstrap.memory_lock: false
bootstrap.system_call_filter: false
#
# Make sure that the heap size is set to about half the memory available
# on the system and that the owner of the process is allowed to use this
# limit.
#
# Elasticsearch performs poorly when the system is swapping the memory.
#
# ---------------------------------- Network -----------------------------------
#
# Set the bind address to a specific IP (IPv4 or IPv6):
#本机IP
network.host: 192.168.100.35
#http.host: 192.168.100.35
#
# Set a custom port for HTTP:
#端口号
http.port: 9200
#transport.tcp.port:9300
#
# For more information, consult the network module documentation.
#
# --------------------------------- Discovery ----------------------------------
#
# 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]"]
#这里用的是单播，节点之间互相发现
discovery.zen.ping.unicast.hosts: ["192.168.100.34", "192.168.100.35","192.168.100.112"]
#
# Prevent the "split brain" by configuring the majority of nodes (total number of master-eligible nodes / 2 + 1):
#
discovery.zen.minimum_master_nodes: 2
#
# For more information, consult the zen discovery module documentation.
#
# ---------------------------------- Gateway -----------------------------------
#
# Block initial recovery after a full cluster restart until N nodes are started:
#
#gateway.recover_after_nodes: 3
#
# For more information, consult the gateway module documentation.
#
# ---------------------------------- Various -----------------------------------
#
# Require explicit names when deleting indices:
#
#action.destructive_requires_name: true

启动即可，机器之间会自动发现，并联系。

这里有一个需要注意的问题：

如果第二台机器上的ES是从第一台机器上复制过去的，如果在data下有数据的话，请一定要清除掉，具体报什么错不记得了，但报错的话，注意下这一点。

然后，访问：hostA:9200/_cluster/healthy?pretty

{
  "cluster_name" : "elasticsearch",
  "status" : "green",
  "timed_out" : false,
  "number_of_nodes" : 2,
  "number_of_data_nodes" : 2,
  "active_primary_shards" : 26,
  "active_shards" : 52,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 0,
  "delayed_unassigned_shards" : 0,
  "number_of_pending_tasks" : 0,
  "number_of_in_flight_fetch" : 0,
  "task_max_waiting_in_queue_millis" : 0,
  "active_shards_percent_as_number" : 100.0
}

上面需要注意节点：

1. 集群健康状态：这时候应该是status：green。
2. 集群节点个数：number_of_nodes : 2
3. 活跃的分片是主分片数量的2倍，因为我这边只有两台数据节点
4. 未分配的分片数目是0：unassigned_shards。

满足上面这四点，集群才算真正搭建成功。