前言
开源实时日志分析ELK平台(ElasticSearch, Logstash, Kibana组成)，能很方便的帮我们收集日志，进行集中化的管理，并且能很方便的进行日志的统计和检索，下面基于ELK的最新版本5.1进行一次整合测试。

ElasticSearch
1.概述：
ElasticSearch是一个高可扩展的开源的全文搜索分析引擎。它允许你快速的存储、搜索和分析大量数据。ElasticSearch通常作为后端程序，为需要复杂查询的应用提供服务。
Elasticsearch是一个基于Lucene的开源分布式搜索引擎，具有分布式多用户能力。Elasticsearch是用java开发，提供Restful接口，能够达到实时搜索、高性能计算；同时Elasticsearch的横向扩展能力非常强，不需要重启服务，基本上达到了零配置。

2.解压ElasticSearch并进入目录：

unzip elasticsearch-5.1.1.zip 
cd elasticsearch-5.1.1

3.启动ElasticSearch服务：

./bin/elasticsearch

因为这里使用的是root账号进行启动服务的，所以会报如下错误：

        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:125) ~[elasticsearch-5.1.1.jar:5.1.1]
        at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:112) ~[elasticsearch-5.1.1.jar:5.1.1]
        at org.elasticsearch.cli.SettingCommand.execute(SettingCommand.java:54) ~[elasticsearch-5.1.1.jar:5.1.1]
        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:96) ~[elasticsearch-5.1.1.jar:5.1.1]
        at org.elasticsearch.cli.Command.main(Command.java:62) ~[elasticsearch-5.1.1.jar:5.1.1]
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:89) ~[elasticsearch-5.1.1.jar:5.1.1]
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:82) ~[elasticsearch-5.1.1.jar:5.1.1]
Caused by: java.lang.RuntimeException: can not run elasticsearch as root
        at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:100) ~[elasticsearch-5.1.1.jar:5.1.1]
        at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:176) ~[elasticsearch-5.1.1.jar:5.1.1]
        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:306) ~[elasticsearch-5.1.1.jar:5.1.1]
        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:121) ~[elasticsearch-5.1.1.jar:5.1.1]
        ... 6 more

错误很明显，不能以root账号来运行elasticsearch，网上有一种解决方法是添加es.insecure.allow.root=true参数，启动方式如下：

./bin/elasticsearch -Des.insecure.allow.root=true

启动日志如下所示：

starts elasticsearch
 
Option                Description                                              
------                -----------                                              
-E <KeyValuePair>     Configure a setting                                      
-V, --version         Prints elasticsearch version information and exits       
-d, --daemonize       Starts Elasticsearch in the background                   
-h, --help            show help                                                
-p, --pidfile <Path>  Creates a pid file in the specified path on start        
-q, --quiet           Turns off standard ouput/error streams logging in console
-s, --silent          show minimal output                                      
-v, --verbose         show verbose output                                      
ERROR: D is not a recognized option

并没有启动成功，但是试了一下在elasticsearch-2.1.1这个版本是可以成功的，官方网站的Issues也给出了说明：

In 5.0.0-alpha3, all of this has been cleaned up. 
The entanglement between system properties and settings has beenremoved. 
This means that the system property es.insecure.allow.root will not automatically 
be converted to a setting which means it's no longer a problem that it's not registered.

更加详细的介绍https://github.com/elastic/elasticsearch/issues/18688

这是出于系统安全考虑设置的条件。由于ElasticSearch可以接收用户输入的脚本并且执行，为了系统安全考虑，建议创建一个单独的用户用来运行ElasticSearch。
4.创建用户组和用户：

groupadd esgroup
useradd esuser -g esgroup -p espassword

更改elasticsearch文件夹及内部文件的所属用户及组：

cd /opt/elk
chown -R esuser:esgroup elasticsearch-5.1.1

切换用户并运行：

su esuser
./bin/elasticsearch

启动日志如下所示：

[esuser@localhost elasticsearch-5.1.1]$ ./bin/elasticsearch
[2017-01-13T11:18:35,020][INFO ][o.e.n.Node               ] [] initializing ...
[2017-01-13T11:18:35,284][INFO ][o.e.e.NodeEnvironment    ] [rBrMTNx] using [1] data paths, mounts [[/ (rootfs)]], net usable_space [21.6gb], net total_space [27.4gb], spins? [unknown], types [rootfs]
[2017-01-13T11:18:35,284][INFO ][o.e.e.NodeEnvironment    ] [rBrMTNx] heap size [1.9gb], compressed ordinary object pointers [true]
[2017-01-13T11:18:35,285][INFO ][o.e.n.Node               ] node name [rBrMTNx] derived from node ID [rBrMTNxCSEehQsfjvxmSgw]; set [node.name] to override
[2017-01-13T11:18:35,308][INFO ][o.e.n.Node               ] version[5.1.1], pid[2612], build[5395e21/2016-12-06T12:36:15.409Z], OS[Linux/3.10.0-327.el7.x86_64/amd64], JVM[Oracle Corporation/Java HotSpot(TM) 64-Bit Server VM/1.8.0_112/25.112-b15]
[2017-01-13T11:18:38,284][INFO ][o.e.p.PluginsService     ] [rBrMTNx] loaded module [aggs-matrix-stats]
[2017-01-13T11:18:38,285][INFO ][o.e.p.PluginsService     ] [rBrMTNx] loaded module [ingest-common]
[2017-01-13T11:18:38,285][INFO ][o.e.p.PluginsService     ] [rBrMTNx] loaded module [lang-expression]
[2017-01-13T11:18:38,285][INFO ][o.e.p.PluginsService     ] [rBrMTNx] loaded module [lang-groovy]
[2017-01-13T11:18:38,285][INFO ][o.e.p.PluginsService     ] [rBrMTNx] loaded module [lang-mustache]
[2017-01-13T11:18:38,285][INFO ][o.e.p.PluginsService     ] [rBrMTNx] loaded module [lang-painless]
[2017-01-13T11:18:38,285][INFO ][o.e.p.PluginsService     ] [rBrMTNx] loaded module [percolator]
[2017-01-13T11:18:38,285][INFO ][o.e.p.PluginsService     ] [rBrMTNx] loaded module [reindex]
[2017-01-13T11:18:38,285][INFO ][o.e.p.PluginsService     ] [rBrMTNx] loaded module [transport-netty3]
[2017-01-13T11:18:38,285][INFO ][o.e.p.PluginsService     ] [rBrMTNx] loaded module [transport-netty4]
[2017-01-13T11:18:38,286][INFO ][o.e.p.PluginsService     ] [rBrMTNx] no plugins loaded
[2017-01-13T11:18:44,427][INFO ][o.e.n.Node               ] initialized
[2017-01-13T11:18:44,441][INFO ][o.e.n.Node               ] [rBrMTNx] starting ...
[2017-01-13T11:18:44,943][INFO ][o.e.t.TransportService   ] [rBrMTNx] publish_address {127.0.0.1:9300}, bound_addresses {[::1]:9300}, {127.0.0.1:9300}
[2017-01-13T11:18:44,976][WARN ][o.e.b.BootstrapCheck     ] [rBrMTNx] max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
[2017-01-13T11:18:44,976][WARN ][o.e.b.BootstrapCheck     ] [rBrMTNx] max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
[2017-01-13T11:18:48,633][INFO ][o.e.c.s.ClusterService   ] [rBrMTNx] new_master {rBrMTNx}{rBrMTNxCSEehQsfjvxmSgw}{N9FXgAA5TjC78HBimEJ9kw}{127.0.0.1}{127.0.0.1:9300}, reason: zen-disco-elected-as-master ([0] nodes joined)
[2017-01-13T11:18:48,762][INFO ][o.e.g.GatewayService     ] [rBrMTNx] recovered [0] indices into cluster_state
[2017-01-13T11:18:48,775][INFO ][o.e.h.HttpServer         ] [rBrMTNx] publish_address {127.0.0.1:9200}, bound_addresses {[::1]:9200}, {127.0.0.1:9200}
[2017-01-13T11:18:48,775][INFO ][o.e.n.Node               ] [rBrMTNx] started

日志中启动了两个端口分别是：9300和9200,9300用于跟其他的节点的传输，9200用于接受HTTP请求，ctrl+c可以结束进程
5.后台运行：

./bin/elasticsearch -d

6.简单连接：

curl 127.0.0.1:9200

结果如下所示：

[root@localhost ~]# curl 127.0.0.1:9200
{
  "name" : "rBrMTNx",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "-noR5DxFRsyvAFvAzxl07g",
  "version" : {
    "number" : "5.1.1",
    "build_hash" : "5395e21",
    "build_date" : "2016-12-06T12:36:15.409Z",
    "build_snapshot" : false,
    "lucene_version" : "6.3.0"
  },
  "tagline" : "You Know, for Search"
}

7.因为elasticsearch安装在虚拟机里面，我希望我的主机也可以访问，需要对config/elasticsearch.yml进行配置：

network.host: 192.168.111.131

192.168.111.131是虚拟机里面的地址，修改完之后重新启动，会出现如下错误日志：

ERROR: bootstrap checks failed
max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]

解决办法：
切换到root用户，修改配置limits.conf

vi /etc/security/limits.conf

添加如下内容：

* soft nofile 65536
* hard nofile 131072
* soft nproc 2048
* hard nproc 4096

修改配置sysctl.conf

vi /etc/sysctl.conf

添加如下内容：

vm.max_map_count=655360

更加详细的参考：Elasticsearch5.0 安装问题集锦
修改完之后重启服务，并在本地浏览器中进行访问，结果如下图所示：

8.停止服务：

ps -ef |grep elasticsearch
kill PID

 

Logstash
Logstash是一个完全开源的工具，可以对你的日志进行收集、过滤，并将其存储供以后使用，参考官网的介绍图：

1.解压进入目录

tar -zxvf logstash-5.1.1.tar.gz
cd logstash-5.1.1

2.添加配置文件

vi config/first-pipeline.conf

添加如下内容：

input {
  log4j {
    host => "192.168.111.131"
    port => 8801
  }
}
output {
    elasticsearch {
        hosts => [ "192.168.111.131:9200" ]
    }
}

3.启动服务

./bin/logstash -f config/first-pipeline.conf

启动成功日志如下：

Sending Logstash's logs to /opt/elk/logstash-5.1.1/logs which is now configured via log4j2.properties
[2017-01-17T11:41:42,978][INFO ][logstash.inputs.log4j    ] Starting Log4j input listener {:address=>"192.168.111.131:8801"}
[2017-01-17T11:41:43,565][INFO ][logstash.inputs.log4j    ] Log4j input
[2017-01-17T11:41:45,658][INFO ][logstash.outputs.elasticsearch] Elasticsearch pool URLs updated {:changes=>{:removed=>[], :added=>["http://192.168.111.131:9200"]}}
[2017-01-17T11:41:45,659][INFO ][logstash.outputs.elasticsearch] Running health check to see if an Elasticsearch connection is working {:url=>#<URI::HTTP:0x3a685472 URL:http://192.168.111.131:9200>, :healthcheck_path=>"/"}
log4j:WARN No appenders could be found for logger (org.apache.http.client.protocol.RequestAuthCache).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
[2017-01-17T11:41:46,090][WARN ][logstash.outputs.elasticsearch] Restored connection to ES instance {:url=>#<URI::HTTP:0x3a685472 URL:http://192.168.111.131:9200>}
[2017-01-17T11:41:46,115][INFO ][logstash.outputs.elasticsearch] Using mapping template from {:path=>nil}
[2017-01-17T11:41:46,357][INFO ][logstash.outputs.elasticsearch] Attempting to install template {:manage_template=>{"template"=>"logstash-*", "version"=>50001, "settings"=>{"index.refresh_interval"=>"5s"}, "mappings"=>{"_default_"=>{"_all"=>{"enabled"=>true, "norms"=>false}, "dynamic_templates"=>[{"message_field"=>{"path_match"=>"message", "match_mapping_type"=>"string", "mapping"=>{"type"=>"text", "norms"=>false}}}, {"string_fields"=>{"match"=>"*", "match_mapping_type"=>"string", "mapping"=>{"type"=>"text", "norms"=>false, "fields"=>{"keyword"=>{"type"=>"keyword"}}}}}], "properties"=>{"@timestamp"=>{"type"=>"date", "include_in_all"=>false}, "@version"=>{"type"=>"keyword", "include_in_all"=>false}, "geoip"=>{"dynamic"=>true, "properties"=>{"ip"=>{"type"=>"ip"}, "location"=>{"type"=>"geo_point"}, "latitude"=>{"type"=>"half_float"}, "longitude"=>{"type"=>"half_float"}}}}}}}}
[2017-01-17T11:41:46,474][INFO ][logstash.outputs.elasticsearch] New Elasticsearch output {:class=>"LogStash::Outputs::ElasticSearch", :hosts=>["192.168.111.131:9200"]}
[2017-01-17T11:41:46,495][INFO ][logstash.pipeline        ] Starting pipeline {"id"=>"main", "pipeline.workers"=>1, "pipeline.batch.size"=>125, "pipeline.batch.delay"=>5, "pipeline.max_inflight"=>125}
[2017-01-17T11:41:46,514][INFO ][logstash.pipeline        ] Pipeline main started
[2017-01-17T11:41:46,935][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=>9600}

New Elasticsearch output {:class=>”LogStash::Outputs::ElasticSearch”, :hosts=>[“192.168.111.131:9200”]}表示已经成功连接了指定的Elasticsearch。

Kibana
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。
1.解压进入目录

tar -zxvf kibana-5.1.1-linux-x86_64.tar.gz
cd kibana-5.1.1-linux-x86_64

2.修改配置文件

vi config/kibana.yml

添加如下配置项：

server.port: 5601
server.host: "192.168.111.130"
elasticsearch.url: "http://192.168.111.131:9200"
kibana.index: ".kibana"

3.启动服务

./bin/kibana

启动成功日志如下：

log   [16:42:01.349] [info][status][plugin:kibana@5.1.1] Status changed from uninitialized to green - Ready
log   [16:42:01.406] [info][status][plugin:elasticsearch@5.1.1] Status changed from uninitialized to yellow - Waiting for Elasticsearch
log   [16:42:01.427] [info][status][plugin:console@5.1.1] Status changed from uninitialized to green - Ready
log   [16:42:01.567] [info][status][plugin:timelion@5.1.1] Status changed from uninitialized to green - Ready
log   [16:42:01.574] [info][listening] Server running at http://192.168.111.130:5601

4.浏览器访问

http://192.168.111.130:5601/

默认第一次需要Configure an index pattern，默认的Index name是logstash-*，直接create就行了。

测试
1.准备一个测试工程，往logstash写数据，同时通过kibana查看数据
log4j maven

<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>

log4j.properties

log4j.rootLogger=DEBUG, logstash
 
log4j.appender.logstash=org.apache.log4j.net.SocketAppender
log4j.appender.logstash.Port=8801
log4j.appender.logstash.RemoteHost=192.168.111.131
log4j.appender.logstash.ReconnectionDelay=60000
log4j.appender.logstash.LocationInfo=true

测试类App

import org.apache.log4j.Logger;
 
public class App {
    private static final Logger LOGGER = Logger.getLogger(App.class);
 
    public static void main(String[] args) throws Exception {
        for (int i = 0; i < 1000; i++) {
            LOGGER.info("Test [" + i + "]");
        }
    }
}

运行App，会出现如下错误：

SocketException: Software caused connection abort: socket write error

解决方法：

vi logstash-core/lib/logstash-core_jars.rb

注释掉#require_jar( ‘org.apache.logging.log4j’, ‘log4j-1.2-api’, ‘2.6.2’ )，然后重启logstash

2.kibana查看数据
点击Discover，然后指定好日期，就可以查看刚刚log4j发送的日志了，如下图所示：

可以指定关键字进行搜索，指定时间范围，指定刷新间隔时间等，更多的功能可以自行去摸索