ElasticSearch 是一款优秀的搜索引擎，用java编写，restful接口的方式进行对接。
1.安装ElasticSearch
安装Java环境
首先检测是否安装java
java -version
echo $JAVA_HOME
如果java的版本过低，建议安装高版本，下面安装的是java 1.8
cd /opt/
wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u66-b17/jdk-8u66-linux-x64.tar.gz"
tar xzf jdk-8u66-linux-x64.tar.gz
上面的下载，如果失效，您可以在我的百度网盘中下载jdk: https://pan.baidu.com/s/1kVwRD2Z
下载文件：jdk-8u66-linux-x64.tar.gz
cd /opt/jdk1.8.0_66/
alternatives --install /usr/bin/java java /opt/jdk1.8.0_66/bin/java 2
alternatives --config java
运行了上面的，会初选一个选择的地方，我的机器显示：
There are 3 programs which provide 'java'.
Selection Command
-----------------------------------------------
* 1 /opt/jdk1.7.0_71/bin/java
+ 2 /opt/jdk1.8.0_45/bin/java
3 /opt/jdk1.8.0_51/bin/java
4 /opt/jdk1.8.0_66/bin/java
Enter to keep the current selection[+], or type selection number: 4
我们安装的是jdk1.8.0.66 所以，我选择的是4，这个看具体情况，jdk1.8.0.66 是第几个，就选择那个数字。
alternatives --install /usr/bin/jar jar /opt/jdk1.8.0_66/bin/jar 2
alternatives --install /usr/bin/javac javac /opt/jdk1.8.0_66/bin/javac 2
alternatives --set jar /opt/jdk1.8.0_66/bin/jar
alternatives --set javac /opt/jdk1.8.0_66/bin/javac
安装完成，检查版本
java -version
java version "1.8.0_66"
Java(TM) SE Runtime Environment (build 1.8.0_66-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.66-b17, mixed mode)
保存到文件 /etc/environment中，当服务器重启的时候加载：
vi /etc/profile
export JAVA_HOME=/opt/jdk1.8.0_66
export JRE_HOME=/opt/jdk1.8.0_66/jre
export PATH=$PATH:/opt/jdk1.8.0_66/bin:/opt/jdk1.8.0_66/jre/bin
重启linux: reboot , 查看是否安装成功
java -version
echo $JAVA_HOME
安装ElasticSearch
cd /tools
wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.1.3.zip
unzip elasticsearch-6.1.3.zip
mv ./elasticsearch-6.1.3 /usr/local/elasticsearch
cd /usr/local
groupadd elasticsearch
useradd -g elasticsearch elasticsearch
chown elasticsearch:elasticsearch -R elasticsearch
上面安装的是es6.
1.设置开机启动： 我是本地，直接把iptables 关掉了
vim /etc/rc.d/rc.local
service iptables stop
su elasticsearch -c "/usr/local/elasticsearch/bin/elasticsearch -d"
一定要注意，elasticSearch不能用root账户启动，elasticSearch不能用root账户启动，elasticSearch不能用root账户启动，重要的说三遍，我这里用的是我新建的elasticsearch账户开机启动
报错：
$./bin/elasticsearch
Java HotSpot(TM) 64-Bit Server VM warning: INFO: os::commit_memory(0x0000000085330000, 2060255232, 0) failed; error='Cannot allocate memory' (errno=12)
#
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 2060255232 bytes for committing reserved memory.
# An error report file with more information is saved as:
# /data/elasticsearch-5.2.2/hs_err_pid26945.log
解决方案：调小启动内存
# vi /usr/local/elasticsearch/config/jvm.options
#-Xms2g
#-Xmx2g
-Xms256m
-Xmx64m
# Xms represents the initial size of total heap space
# Xmx represents the maximum size of total heap space
-Xms128m
-Xmx128m
上面设置的分配的内存的最大值为256MB和最小值64mb，您可以根据自己的机器情况设置内存大小。
上面的内存一定要修改设置，除非你的机器内存很大，2G的机器，建议按照上面的修改内存大小，否则将启动失败
下面是一个使用默认配置启动失败的log
[root@vultr local]# su elasticsearch -c "/usr/local/elasticsearch/bin/elasticsearch "
[2018-06-23T05:31:43,284][INFO ][o.e.n.Node ] [] initializing ...
[2018-06-23T05:31:43,458][INFO ][o.e.e.NodeEnvironment ] [3NDH7pj] using [1] data paths, mounts [[/ (rootfs)]], net usable_space [30.2gb], net total_space [39.3gb], types [rootfs]
[2018-06-23T05:31:43,458][INFO ][o.e.e.NodeEnvironment ] [3NDH7pj] heap size [1015.6mb], compressed ordinary object pointers [true]
[2018-06-23T05:31:43,461][INFO ][o.e.n.Node ] node name [3NDH7pj] derived from node ID [3NDH7pjFRkqGJK-esxelQw]; set [node.name] to override
[2018-06-23T05:31:43,461][INFO ][o.e.n.Node ] version[6.1.3], pid[1566], build[af51318/2018-01-26T18:22:55.523Z], OS[Linux/3.10.0-862.3.2.el7.x86_64/amd64], JVM[Oracle Corporation/Java HotSpot(TM) 64-Bit Server VM/1.8.0_66/25.66-b17]
[2018-06-23T05:31:43,461][INFO ][o.e.n.Node ] JVM arguments [-Xms256m, -Xmx64m, -Xms1g, -Xmx1g, -XX:+UseConcMarkSweepGC, -XX:CMSInitiatingOccupancyFraction=75, -XX:+UseCMSInitiatingOccupancyOnly, -XX:+AlwaysPreTouch, -Xss1m, -Djava.awt.headless=true, -Dfile.encoding=UTF-8, -Djna.nosys=true, -XX:-OmitStackTraceInFastThrow, -Dio.netty.noUnsafe=true, -Dio.netty.noKeySetOptimization=true, -Dio.netty.recycler.maxCapacityPerThread=0, -Dlog4j.shutdownHookEnabled=false, -Dlog4j2.disable.jmx=true, -XX:+HeapDumpOnOutOfMemoryError, -Des.path.home=/usr/local/elasticsearch, -Des.path.conf=/usr/local/elasticsearch/config]
[2018-06-23T05:31:45,916][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [aggs-matrix-stats]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [analysis-common]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [ingest-common]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [lang-expression]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [lang-mustache]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [lang-painless]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [mapper-extras]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [parent-join]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [percolator]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [reindex]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [repository-url]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [transport-netty4]
[2018-06-23T05:31:45,917][INFO ][o.e.p.PluginsService ] [3NDH7pj] loaded module [tribe]
[2018-06-23T05:31:45,918][INFO ][o.e.p.PluginsService ] [3NDH7pj] no plugins loaded
Killed
重新启动即可。
2.配置
vim /usr/local/elasticsearch/config/elasticsearch.yml
修改如下：
cluster.name: TA-application
node.name: node-210
network.host: 192.168.0.210
其中cluster.name 是集群名称，这个不要使用默认的，要修改，去掉注释，如果有多个机器，加入同一个集群，那么这个值必须一样
noide.name 是集群里面每个节点的值，也就是当前机器的节点的值，这个值，每个节点要不一样。
network host 改成当前的内网ip