elastic5.4安装错误解决

首先，我们从官网下载：
（官网：https://www.elastic.co/downloads/elasticsearch）(推荐下载deb或者rpm包,否则坑很多)

启动 (需要依赖java环境)

bin/elasticsearch

这时候会提示以下错误：

[2017-01-17T21:54:48,798][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:125) ~[elasticsearch-5.1.2.jar:5.1.2]
        at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:112) ~[elasticsearch-5.1.2.jar:5.1.2]
        at org.elasticsearch.cli.SettingCommand.execute(SettingCommand.java:54) ~[elasticsearch-5.1.2.jar:5.1.2]
        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:122) ~[elasticsearch-5.1.2.jar:5.1.2]
        at org.elasticsearch.cli.Command.main(Command.java:88) ~[elasticsearch-5.1.2.jar:5.1.2]
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:89) ~[elasticsearch-5.1.2.jar:5.1.2]
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:82) ~[elasticsearch-5.1.2.jar:5.1.2]
Caused by: java.lang.RuntimeException: can not run elasticsearch as root
        at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:100) ~[elasticsearch-5.1.2.jar:5.1.2]
        at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:176) ~[elasticsearch-5.1.2.jar:5.1.2]
        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:306) ~[elasticsearch-5.1.2.jar:5.1.2]
        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:121) ~[elasticsearch-5.1.2.jar:5.1.2]
        ... 6 more

这个错误的原因是elasticsearch不允许使用root启动，因此我们要解决这个问题需要新建一个用户来启动elasticsearch

具体操作如下：

groupadd elsearch
useradd elsearch -g elsearch -p elsearch
chmod -R 775 config
chown -R elsearch:elsearch elasticsearch 

这个时候在这个用户去启动elasticsearch，发现可以启动，但是无法通过web - localhost:9200访问

修改config/elasticsearch.yml 文件

# ---------------------------------- Network -----------------------------------
#
# Set the bind address to a specific IP (IPv4 or IPv6):
#
network.host: 192.168.0.155
#
# Set a custom port for HTTP:
#
http.port: 9200
#
# For more information, see the documentation at:
# <http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-network.html>

直接运行bin/elasticsearch文件启动elasticsearch,发现报错

max virtual memory areas vm.max_map_count [65530] likely too low, increase to at least [262144]

于是我临时提高了vm.max_map_count的大小 
*此操作需要root权限

sysctl -w vm.max_map_count=262144

查看修改结果

sysctl -a|grep vm.max_map_count
vm.max_map_count = 262144

接下来就可以启动elasticsearch了，启动完成使用浏览器访问http://localhost:9200

{
  "name" : "Vampire by Night",
  "cluster_name" : "elasticsearch",
  "version" : {
    "number" : "5.0.0-alpha3",
    "build_hash" : "cad959b",
    "build_date" : "2016-05-26T08:25:57.564Z",
    "build_snapshot" : false,
    "lucene_version" : "6.0.0"
  },
  "tagline" : "You Know, for Search"
}