Centos7中安装elasticsearch
第一步：必须要有jre支持
elasticsearch是用Java实现的，跑elasticsearch必须要有jre支持，所以必须先安装jre
第二步：下载elasticsearch
进入官方下载 https://www.elastic.co/downloads/elasticsearch
因为是centos中运行 所以我们选 tar.gz压缩包；
下载后 用ftp上传到centos里 我们把这个文件上传到 /home/data/下
第三步：安装和配置elasticsearch
进入data目录 解压
[root@bogon ~]# cd /home/data/
[root@bogon data]# tar -zxvf elasticsearch-5.5.2.tar.gz
新建目录 剪切文件到新目录
[root@bogon data]# cd
[root@bogon ~]# mkdir /home/es/
[root@bogon ~]# mv /home/data/elasticsearch-5.5.2 /home/es/
我们执行，来启动 elasticsearch
[root@bogon ~]# sh /home/es/elasticsearch-5.5.2/bin/elasticsearch
报错了：
[2017-09-07T19:43:10,628][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [] uncaught exception in thread [main]
org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root
at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:127) ~[elasticsearch-5.5.2.jar:5.5.2]
at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:114) ~[elasticsearch-5.5.2.jar:5.5.2]
at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:67) ~[elasticsearch-5.5.2.jar:5.5.2]
at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:122) ~[elasticsearch-5.5.2.jar:5.5.2]
at org.elasticsearch.cli.Command.main(Command.java:88) ~[elasticsearch-5.5.2.jar:5.5.2]
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:91) ~[elasticsearch-5.5.2.jar:5.5.2]
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:84) ~[elasticsearch-5.5.2.jar:5.5.2]
Caused by: java.lang.RuntimeException: can not run elasticsearch as root
at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:106) ~[elasticsearch-5.5.2.jar:5.5.2]
at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:194) ~[elasticsearch-5.5.2.jar:5.5.2]
at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:351) ~[elasticsearch-5.5.2.jar:5.5.2]
at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:123) ~[elasticsearch-5.5.2.jar:5.5.2]
... 6 more
意思是不能用root用户来启动，那我们新建一个用户来启动
[root@bogon ~]# useradd elastic
[root@bogon ~]# chown -R elastic:elastic /home/es/elasticsearch-5.5.2/
新建elastic用户 并且把目录权限赋予给elastic
我们切换成elastic用户，然后执行
[root@bogon ~]# su elastic
[elastic@bogon root]$ sh /home/es/elasticsearch-5.5.2/bin/elasticsearch
出来一大串info 说明成功了，但是这种方式是前台运行，不方便我们操作其他的 我们加下 -d 后台运行
先ctrl+c退出执行；
[elastic@bogon root]$ sh /home/es/elasticsearch-5.5.2/bin/elasticsearch -d
我们来检查下是否启动成功
[elastic@bogon root]$ ps -ef | grep elasticsearch
elastic 2962 1 23 19:48 pts/1 00:00:02 /home/java/jdk1.8.0_144/bin/java -Xms2g -Xmx2g -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -XX:+AlwaysPreTouch -server -Xss1m -Djava.awt.headless=true -Dfile.encoding=UTF-8 -Djna.nosys=true -Djdk.io.permissionsUseCanonicalPath=true -Dio.netty.noUnsafe=true -Dio.netty.noKeySetOptimization=true -Dio.netty.recycler.maxCapacityPerThread=0 -Dlog4j.shutdownHookEnabled=false -Dlog4j2.disable.jmx=true -Dlog4j.skipJansi=true -XX:+HeapDumpOnOutOfMemoryError -Des.path.home=/home/es/elasticsearch-5.5.2 -cp /home/es/elasticsearch-5.5.2/lib/* org.elasticsearch.bootstrap.Elasticsearch -d
elastic 2977 2849 0 19:48 pts/1 00:00:00 grep --color=auto elasticsearch
注意 有朋友经常出现 如下错误
ERROR: [2] bootstrap checks failed
[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
[2]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
解决方案：
ERROR: [2] bootstrap checks failed
[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
[2]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
启动报这个错误；
问题1 [1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
修改/etc/security/limits.conf文件，添加或修改如下行： （请切换到root用户 然后强制修改文件）
* hard nofile 65536
* soft nofile 65536
问题2 [2]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
$ sudo sysctl -w vm.max_map_count=2621441
或者修改 /etc/sysctl.conf 文件，添加 “vm.max_map_count”设置 永久改变(sudo sysctl -p /etc/sysctl.conf生效)。
/sbin/sysctl -p 执行下 让/etc/sysctl.conf 立即生效
设置后，可以使用
我们来验证下服务是否正常运行 curl http://localhost:9200
[elastic@bogon root]$ curl http://localhost:9200
{
"name" : "K22mJd5",
"cluster_name" : "elasticsearch",
"cluster_uuid" : "R2qfXKtrQl2PwKdJMmPuMA",
"version" : {
"number" : "5.5.2",
"build_hash" : "b2f0c09",
"build_date" : "2017-08-14T12:33:14.154Z",
"build_snapshot" : false,
"lucene_version" : "6.6.0"
},
"tagline" : "You Know, for Search"
}
出来这个 说明配置OK。
第四步：允许外网连接配置
前面我们配置的仅仅是本机使用 但是我们比如集群以及其他机器连接 ，则需要配置下。
可以修改 /home/es/elasticsearch/config/elasticsearch.yml 文件
把 network.host 和 http.port 前面的 备注去掉 然后Host改成你的局域网IP即可
修改后 保存退出
然后我们把防火墙也关了
systemctl stop firewalld.service
systemctl disable firewalld.service 禁止防火墙开机启动
Elasticsearch6.3 max number of threads [2048] for user [*] is too low, increase to at least [4096]异常
根据linux系统差异，有时候需要来点终极解决方案
新建： /etc/security/limits.d/test-limits.conf
cat>>test-limits.conf
然后加下内容：
* soft nofile 65536
* hard nofile 131072
* soft nproc 4096
* hard nproc 4096
ctrl+d保存即可；
然后重启服务器即可；
最后我们重启下elasticsearch服务
ps -ef | grep elasticsearch 找到进程号
然后kill -9 进程号
再启动下elasticsearch
我们用谷歌浏览器请求下 http://192.168.1.108:9200/
OK 出现这东西 才算配置完成；
