ELK日志系统介绍
开源实时日志分析ELK平台能够完美的解决我们上述的问题，ELK由ElasticSearch、Logstash和Kiabana三个开源工具组成。官方网站：https://www.elastic.co/products

1、Elasticsearch是个开源分布式搜索引擎，它的特点有：分布式，零配置，自动发现，索引自动分片，索引副本机制，restful风格接口，多数据源，自动搜索负载等

2、Logstash是一个完全开源的工具，他可以对你的日志进行收集、过滤，并将其存储供以后使用（如，搜索）

3、Kibana 也是一个开源和免费的工具，它Kibana可以为 Logstash 和 ElasticSearch 提供的日志分析友好的 Web 界面，可以帮助您汇总、分析和搜索重要数据日志

安装环境准备
首先需要下载好相关的软件安装包
官方网站：https://www.elastic.co
https://artifacts.elastic.co/downloads/logstash/logstash-5.3.1.tar.gz
https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-5.3.1.tar.gz
https://artifacts.elastic.co/downloads/kibana/kibana-5.3.1-linux-x86_64.tar.gz
安装配置JAVA环境

JDK版本：jdk-8u144-linux-x64.tar.gz
[root@centos7-1 ~]# cat /etc/redhat-release
CentOS Linux release 7.4.1708 (Core)
[root@centos7-1 ~]# uname -r
3.10.0-693.el7.x86_64
[root@centos7-1 ~]# tar zxf jdk-8u144-linux-x64.tar.gz -C /usr/local/
[root@centos7-1 ~]# ln -s /usr/local/jdk1.8.0_144 /usr/local/jdk
[root@centos7-1 ~]# cat >>/etc/profile <<EOF
export JAVA_HOME=/usr/local/jdk
export PATH=$PATH: $JAVA_HOME/bin
export CLASSPATH=.CLASSPATH:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
EOF
[root@centos7-1 ~]# source /etc/profile
[root@centos7-1 ~]# java -version
java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)

安装Elasticserach
修改系统参数

[root@centos7-1 config]# vim /etc/sysctl.conf
#增加下面的配置
vm.max_map_count=655360
[root@centos7-1 config]# sysctl -p
vm.max_map_count = 655360
[root@centos7-1 config]# tail -5 /etc/security/limits.conf
* soft nofile 65536
* hard nofile 131072
* soft nproc 65536
* hard nproc 131072
# End of file

[root@centos7-1 config]# vim /etc/security/limits.d/20-nproc.conf
#增加下面的配置
elk        soft    nproc     65536

创建用户与目录

[root@centos7-1 config]# useradd elk
[root@centos7-1 config]# mkdir /elk/data /elk/logs -p
[root@centos7-1 config]# chown -R elk.elk /elk/
[root@centos7-1 config]# chown -R elk.elk /usr/local/elasticsearch/

安装与配置

[root@centos7-1 ~]# tar zxf elasticsearch-5.3.1.tar.gz -C /usr/local/
[root@centos7-1 ~]# ln -s /usr/local/elasticsearch-5.3.1 /usr/local/elasticsearch
[root@centos7-1 ~]# cd /usr/local/elasticsearch/config/

修改配置文件

[root@centos7-1 config]# egrep -v "^#|^$" elasticsearch.yml
cluster.name: myelk    #集群名
node.name: centos7-1
path.data: /elk/data
path.logs: /elk/logs
network.host: 0.0.0.0
http.port: 9200
discovery.zen.ping.unicast.hosts: ["host1", "host2"]

启动服务

[root@centos7-1 config]# su - elk
[elk@centos7-1 ~]$ who
root     pts/0        2017-10-13 22:22 (10.0.0.1)
[elk@centos7-1 ~]$ cd /usr/local/elasticsearch/bin/
[elk@centos7-1 bin]$ ./elasticsearch&

安装Logstash

[root@centos7-1 ~]# tar zxf logstash-5.3.1.tar.gz -C /usr/local/
[root@centos7-1 ~]# /usr/local/logstash-5.3.1/bin/logstash -e \'input { stdin { } } output { stdout {} }\'
Sending Logstash\'s logs to /usr/local/logstash-5.3.1/logs which is now configured via log4j2.properties
[2017-10-16T01:39:36,983][INFO ][logstash.setting.writabledirectory] Creating directory {:setting=>"path.queue", :path=>"/usr/local/logstash-5.3.1/data/queue"}
[2017-10-16T01:39:37,181][INFO ][logstash.agent  ] No persistent UUID file found. Generating new UUID {:uuid=>"a2e3b22a-4785-42f6-a073-f7fad4d60a44", :path=>"/usr/local/logstash-5.3.1/data/uuid"}
[2017-10-16T01:39:37,623][INFO ][logstash.pipeline] Starting pipeline {"id"=>"main", "pipeline.workers"=>1, "pipeline.batch.size"=>125, "pipeline.batch.delay"=>5, "pipeline.max_inflight"=>125}
[2017-10-16T01:39:37,700][INFO ][logstash.pipeline  ] Pipeline main started
The stdin plugin is now waiting for input:
[2017-10-16T01:39:38,042][INFO ][logstash.agent  ] Successfully started Logstash API endpoint {:port=>9600}
hello
2017-10-16T05:39:45.692Z centos7-1 hello

创始配置文件

[root@centos7-1 logstash-5.3.1]# cd config/
[root@centos7-1 config]# ll
total 20
-rw-rw-r-- 1 root root 1738 Apr 17 12:07 jvm.options
-rw-rw-r-- 1 root root 3958 Apr 17 12:07 log4j2.properties
-rw-rw-r-- 1 root root 4433 Apr 17 12:07 logstash.yml
-rw-rw-r-- 1 root root 1701 Apr 17 12:07 startup.options
[root@centos7-1 config]# vim logstash.conf
input { stdin { } }
output {
    stdout { codec=> rubydebug }
}

Logstash 使用 input 和 output 定义收集日志时的输入和输出的相关配置，本例中 input 定义了一个叫 “stdin” 的 input ， output 定义一个叫 “stdout” 的 output 。无论我们输入什么字符， Logstash 都会按照某种格式来返回我们输入的字符，其中 output 被定义为 “stdout” 并使用了 codec 参数来指定 logstash 输出格式
[root@centos7-1 config]# /usr/local/logstash-5.3.1/bin/logstash -f /usr/local/logstash-5.3.1/config/logstash.conf

安装Kibana

[root@centos7-1 ~]# tar zxf kibana-5.3.1-linux-x86_64.tar.gz -C /usr/local/
[root@centos7-1 ~]# cd /usr/local/kibana-5.3.1-linux-x86_64/config/
[root@centos7-1 config]# vim kibana.yml
# Kibana is served by a back end server. This setting specifies the port to use.
server.port: 5601
# To allow connections from remote users, set this parameter to a non-loopback address.
server.host: "10.0.0.5"
# The URL of the Elasticsearch instance to use for all your queries.
elasticsearch.url: "http://10.0.0.5:9200"
# Kibana uses an index in Elasticsearch to store saved searches, visualizations and
# dashboards. Kibana creates a new index if the index doesn\'t already exist.
kibana.index: ".kibana"

启动服务
[root@centos7-1 config]# /usr/local/kibana-5.3.1-linux-x86_64/bin/kibana &

[root@centos7-1 config]# lsof -i :5601
COMMAND   PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
node  11535 root  12u  IPv4  30703  0t0  TCP centos7-1:esmagent (LISTEN)

登陆WEB界面

测试Kibana与Elasticsearch连接

相关组件安装完成后，就需要测试下几个组件之间能否相互协同工作，也就是能正常收集日志，存储日志并展示日志信息

[root@centos7-1 config]# cd /usr/local/logstash-5.3.1/config/
[root@centos7-1 config]# vim logstash.conf
input {
       stdin { }
      }
output {
    elasticsearch {
         action => "index"
         hosts => "10.0.0.5:9200"
         index => "logstash-%{+YYYY-MM}"
   }
}  
[root@centos7-1 config]# /usr/local/logstash-5.3.1/bin/logstash -f /usr/local/logstash-5.3.1/config/logstash.conf

登陆WEB查看是否有日志产生