ELK - nginx 日志分析及繪圖

本文轉載自查看原文 2019-09-14 17:16 2057 Linux

1. 前言

先上一張整體的效果圖：

上面這張圖就是通過 ELK 分析 nginx 日志所得到的數據，通過 kibana 的功能展示出來的效果圖。是不是這樣對日志做了解析，想要知道的數據一目了然。接下來就是實現過程實錄。

2. 實現過程

通過上一篇：ELK 部署文檔已經對 ELK + filebeat 獲取 nginx 做了詳細的配置介紹，這里重點就不在安裝 ELK 上面了。下面這邊的內容，主要是針對 logstash 配置文件的編寫和 kibana web界面的配置。

主機信息在申明下，和上一篇一樣：

2.1 nginx 日志格式編寫

在編寫logstash 文件之前，得有一個標准輸入輸出格式，這個格式通用的就是 json 格式。

首先，考慮如何才能獲取 json 格式的日志，當然可以直接通過修改 nginx 日志的格式來實現，因此開始修改 nginx 日志格式。如果獲取的日志無法修改json 格式，則可以通過正則表達式來匹配。

在nginx 配置文件中添加如下日志格式：

http {
…
    log_format main_json '{"domain":"$server_name",'
    '"http_x_forwarded_for":"$http_x_forwarded_for",'
    '"time_local":"$time_iso8601",'
    '"request":"$request",'
    '"request_body":"$request_body",'
    '"status":$status,'
    '"body_bytes_sent":"$body_bytes_sent",'
    '"http_referer":"$http_referer",'
    '"upstream_response_time":"$upstream_response_time",'
    '"request_time":"$request_time",'
    '"http_user_agent":"$http_user_agent",'
    '"upstream_addr":"$upstream_addr",'
    '"upstream_status":"$upstream_status"}';


….
}

定義的這個nginx 日志格式叫 main_json 后面的配置文件，都可以引用這個日志格式。除了nginx 日志參數以外，還可以通過配置文件來自行添加自定義參數，比如獲取用戶的真實ip

於是編寫一個自定義變量的配置文件：

[root@192.168.118.16 ~]#vim /etc/nginx/location.conf

#set $real_ip $remote_addr;
if ( $http_x_forwarded_for ~ "^(\d+\.\d+\.\d+\.\d+)" ) {
        set $real_ip $1;
}

這個配置文件只是為了獲取用戶的真實IP，變量名為： real_ip 需要在nginx.conf 中引用，在剛才的配置文件中也加入該變量，完整日志格式如下：

    log_format main_json '{"domain":"$server_name",'
    '"real_ip":"$real_ip",'
    '"http_x_forwarded_for":"$http_x_forwarded_for",'
    '"time_local":"$time_iso8601",'
    '"request":"$request",'
    '"request_body":"$request_body",'
    '"status":$status,'
    '"body_bytes_sent":"$body_bytes_sent",'
    '"http_referer":"$http_referer",'
    '"upstream_response_time":"$upstream_response_time",'
    '"request_time":"$request_time",'
    '"http_user_agent":"$http_user_agent",'
    '"upstream_addr":"$upstream_addr",'
    '"upstream_status":"$upstream_status"}';

注釋掉該行：

#access_log  /var/log/nginx/access.log  main;

接下來，編寫一個nginx 配置文件端口為 9527 作為測試使用

[root@192.168.118.16 ~]#vim /etc/nginx/conf.d/server_9527.conf
server {
    listen 9527;
    server_name localhost;
    include location.conf;
    location / {
        root /www/9527/;
        index index.html;
        access_log /www/log/access.log main_json;
        error_log /www/log/error.log;
    }
    location /shop {
        root /www/9527;
        access_log /www/log/shop_access.log main_json;
        error_log /www/log/shop_error.log;
    }
}

[root@192.168.118.16 ~]#mkdir -p /www/{9527,log}
[root@192.168.118.16 ~]#cd /www/9527/
[root@192.168.118.16 /www/9527]#vim index.html
hello, 9527
[root@192.168.118.16 /www/9527]#mkdir -pv /www/9527/shop
[root@192.168.118.16 /www/9527]#vim /www/9527/shop/index.html
出售9527

[root@192.168.118.16 /www/9527]#nginx -t
[root@192.168.118.16 /www/9527]#nginx -s reload

Nginx 配置完成，重新加載，訪問測試：

[root@192.168.118.16 ~]#curl http://192.168.118.16:9527/index.html
hello, 9527
[root@192.168.118.16 ~]#curl http://192.168.118.16:9527/shop/index.html
出售9527

頁面訪問正常，查看日志：

[root@192.168.118.16 ~]#ll -tsh /www/log/
total 8.0K
4.0K -rw-r--r--  1 root root 346 Sep 14 14:35 shop_access.log
4.0K -rw-r--r--. 1 root root 341 Sep 14 14:35 access.log
   0 -rw-r--r--. 1 root root   0 Sep 14 14:35 error.log
   0 -rw-r--r--  1 root root   0 Sep 14 14:34 shop_error.log

日志文件已生成，查看日志格式：

[root@192.168.118.16 ~]#cat /www/log/access.log 
{"domain":"localhost","real_ip":"","http_x_forwarded_for":"-","time_local":"2019-09-14T14:35:11+08:00","request":"GET /index.html HTTP/1.1","request_body":"-","status":200,"body_bytes_sent":"12","http_referer":"-","upstream_response_time":"-","request_time":"0.000","http_user_agent":"curl/7.29.0","upstream_addr":"-","upstream_status":"-"}

定義的 json 格式已經被引用到，nginx日志格式配置完成，接下來就是通過filebeat 將nginx 日志傳遞給 logstash

2.2 filebeat 傳輸 nginx 日志

這里在上一篇的基礎上做修改，直接修改 filebeat 配置文件：

[root@192.168.118.16 ~]#vim /etc/filebeat/modules.d/nginx.yml

重啟 filebeat 服務

[root@192.168.118.16 ~]#systemctl restart filebeat

2.3 logstash 配置文件編寫

通過上面的步驟，filebeat 已經將 nginx 日志傳輸過來了，接下來就看 logstash 要怎么接收日志數據了，還是通過循序漸進的方式來編寫。

首先將日志數據打印到屏幕，保證數據的正確性。

從 nginx.conf 啟動 logstash。通過瀏覽器訪問 nginx 9527端口產生日志數據。

這里啟動 logstash 可以添加修改自動重載的模式，這樣當修改了 nginx.conf 時，不必頻繁的去關閉重啟。

[root@192.168.118.15 /etc/logstash/conf.d]#logstash -f nginx.conf  --config.reload.automatic

通過抓取一段 json 數據，分析下：

{
    "@timestamp" => 2019-09-14T06:52:16.056Z,
      "@version" => "1",
        "source" => "/www/log/access.log",
         "input" => {
        "type" => "log"
    },
          "beat" => {
            "name" => "web-node1",
         "version" => "6.8.2",
        "hostname" => "web-node1"
    },
          "host" => {
                 "name" => "web-node1",
         "architecture" => "x86_64",
                   "id" => "4b3b32a1db0343458c4942a10c79acef",
                   "os" => {
                "name" => "CentOS Linux",
            "codename" => "Core",
              "family" => "redhat",
            "platform" => "centos",
             "version" => "7 (Core)"
        },
        "containerized" => false
    },
           "log" => {
        "file" => {
            "path" => "/www/log/access.log"
        }
    },
          "tags" => [
        [0] "beats_input_codec_plain_applied"
    ],
    "prospector" => {
        "type" => "log"
    },
       "fileset" => {
        "module" => "nginx",
          "name" => "access"
    },
        "offset" => 9350,
         "event" => {
        "dataset" => "nginx.access"
    },
       "message" => "{\"domain\":\"localhost\",\"real_ip\":\"\",\"http_x_forwarded_for\":\"-\",\"time_local\":\"2019-09-14T14:52:15+08:00\",\"request\":\"GET / HTTP/1.1\",\"request_body\":\"-\",\"status\":304,\"body_bytes_sent\":\"0\",\"http_referer\":\"-\",\"upstream_response_time\":\"-\",\"request_time\":\"0.000\",\"http_user_agent\":\"Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36\",\"upstream_addr\":\"-\",\"upstream_status\":\"-\"}"
}

logstash 輸出內容

這里面數據很多，但是這里的有些數據不是必要的，應該保留需要的數據，而剔除沒必要的數據，使 json 看起來更加簡潔。

首先來查看這段 json ，發現真正的 nginx 日志數據都存在 message 里面，其他的都是一些主機服務相關的信息，但是 message 看起來亂糟糟的，簡直沒法看。既然采用的 json 格式，那就能夠格式化。

修改配置文件如下：

{
                  "@version" => "1",
                      "host" => {
                   "os" => {
                "name" => "CentOS Linux",
             "version" => "7 (Core)",
              "family" => "redhat",
            "platform" => "centos",
            "codename" => "Core"
        },
                 "name" => "web-node1",
                   "id" => "4b3b32a1db0343458c4942a10c79acef",
         "architecture" => "x86_64",
        "containerized" => false
    },
    "upstream_response_time" => "-",
                      "beat" => {
            "name" => "web-node1",
         "version" => "6.8.2",
        "hostname" => "web-node1"
    },
                    "domain" => "localhost",
              "request_body" => "-",
                       "log" => {
        "file" => {
            "path" => "/www/log/access.log"
        }
    },
           "http_user_agent" => "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36",
                "prospector" => {
        "type" => "log"
    },
              "http_referer" => "-",
                   "real_ip" => "",
                   "fileset" => {
        "module" => "nginx",
          "name" => "access"
    },
           "upstream_status" => "-",
           "body_bytes_sent" => "0",
                "@timestamp" => 2019-09-14T07:03:36.087Z,
      "http_x_forwarded_for" => "-",
                    "status" => 304,
                    "source" => "/www/log/access.log",
                     "input" => {
        "type" => "log"
    },
                "time_local" => "2019-09-14T15:03:28+08:00",
              "request_time" => "0.000",
             "upstream_addr" => "-",
                      "tags" => [
        [0] "beats_input_codec_plain_applied"
    ],
                    "offset" => 11066,
                     "event" => {
        "dataset" => "nginx.access"
    },
                   "request" => "GET / HTTP/1.1"
}

logstash 輸出內容

將這兩次獲取的數據進行一個對比，下面這個數據 message 被刪除了，但是 message 中的每個字段都獨立出來了。這樣的好處：

　　（1）日志信息更加清晰，能夠准確的定位到某一個字段；

　　（2）為后面存儲到 elasticsearch 中，進行查詢或者篩選做好了准備。

上面這個操作就等於是將原來的 message 分列存放了。

上面這個json 發現有兩個時間：

　　@timestamp - 格林尼治時間 - logstash 獲取日志時間

　　Time_local - 東八區時間 - nginx日志記錄時間

這兩個時間的分鍾和秒鍾並不一致，而后面過濾日志采用的是 @timestamp 時間，也就是 logstash 時間，這就會造成 nginx 日志時間不准確的現象，因此需要將兩個時間修改為一致。

{
                  "@version" => "1",
                      "host" => {
                 "name" => "web-node1",
                   "os" => {
                "name" => "CentOS Linux",
             "version" => "7 (Core)",
              "family" => "redhat",
            "platform" => "centos",
            "codename" => "Core"
        },
                   "id" => "4b3b32a1db0343458c4942a10c79acef",
         "architecture" => "x86_64",
        "containerized" => false
    },
    "upstream_response_time" => "-",
                      "beat" => {
            "name" => "web-node1",
         "version" => "6.8.2",
        "hostname" => "web-node1"
    },
                    "domain" => "localhost",
              "request_body" => "-",
                       "log" => {
        "file" => {
            "path" => "/www/log/access.log"
        }
    },
           "http_user_agent" => "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36",
                "prospector" => {
        "type" => "log"
    },
              "http_referer" => "-",
                   "real_ip" => "",
                   "fileset" => {
        "module" => "nginx",
          "name" => "access"
    },
           "upstream_status" => "-",
           "body_bytes_sent" => "0",
                    "status" => 304,
      "http_x_forwarded_for" => "-",
                "@timestamp" => 2019-09-14T07:14:46.000Z,
                    "source" => "/www/log/access.log",
                     "input" => {
        "type" => "log"
    },
                "time_local" => "2019-09-14T15:14:46+08:00",
              "request_time" => "0.000",
             "upstream_addr" => "-",
                      "tags" => [
        [0] "beats_input_codec_plain_applied"
    ],
                    "offset" => 11495,
                     "event" => {
        "dataset" => "nginx.access"
    },
                   "request" => "GET / HTTP/1.1"
}

logstash 輸出內容

現在，對比兩個時間的分鍾和秒鍾，完全一致了。接下來，刪除一些不必要的字段，並重命名一些字段名，修改配置文件如下：

{
           "@version" => "1",
              "agent" => "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36",
             "domain" => "localhost",
       "request_body" => "-",
                "log" => {
        "file" => {
            "path" => "/www/log/access.log"
        }
    },
       "http_referer" => "-",
      "response_time" => [
        [0] "-"
    ],
            "real_ip" => "",
            "fileset" => {
        "module" => "nginx",
          "name" => "access"
    },
    "upstream_status" => "-",
    "body_bytes_sent" => "0",
             "status" => 304,
         "@timestamp" => 2019-09-14T07:22:14.000Z,
         "time_local" => "2019-09-14T15:22:14+08:00",
       "request_time" => "0.000",
      "upstream_addr" => "-",
    "x_forwarded_for" => [
        [0] "-"
    ],
            "request" => "GET / HTTP/1.1"
}

logstash 輸出內容

經過重命名和刪除沒有的字段，json 也變的精簡了很多，這樣存儲 elasticsearch 消耗的存儲空間也響應的變小了。

接下來就可以將數據寫入到 elasticsearch 中了。在這之前，做的都是 access.log，壓根就沒考慮到 error.log 的格式，因為 nginx 中 error.log 日志格式無法自定義。

嘗試訪問一個錯誤uri 來查看下獲取到的數據：

[WARN ] 2019-09-14 15:25:34.300 [[main]>worker3] json - Error parsing json {:source=>"message", :raw=>"2019/09/14 15:25:29 [error] 2122#0: *33 open() \"/www/9527/123.html\" failed (2: No such file or directory), client: 192.168.118.41, server: localhost, request: \"GET /123.html HTTP/1.1\", host: \"192.168.118.16:9527\"", :exception=>#<LogStash::Json::ParserError: Unexpected character ('/' (code 47)): Expected space separating root-level values
 at [Source: (byte[])"2019/09/14 15:25:29 [error] 2122#0: *33 open() "/www/9527/123.html" failed (2: No such file or directory), client: 192.168.118.41, server: localhost, request: "GET /123.html HTTP/1.1", host: "192.168.118.16:9527""; line: 1, column: 6]>}

{
    "@timestamp" => 2019-09-14T07:25:33.173Z,
      "@version" => "1",
           "log" => {
        "file" => {
            "path" => "/www/log/error.log"
        }
    },
       "fileset" => {
        "module" => "nginx",
          "name" => "error"
    },
       "message" => "2019/09/14 15:25:29 [error] 2122#0: *33 open() \"/www/9527/123.html\" failed (2: No such file or directory), client: 192.168.118.41, server: localhost, request: \"GET /123.html HTTP/1.1\", host: \"192.168.118.16:9527\""
}

logstash 輸出內容

error.log 過來的數據就變成上面這個樣子了。這又是個問題，做 ELK 一是為了分析數據，二是為了盡快排錯，如果 ELK 連這個都做不到，那就有點雞肋了。

上面的這個格式看起來又是很亂了，nginx 錯誤日志都在 message 中，雖然nginx 錯誤日志無法定義格式，但是 logstash 可以通過正則表達式來將它轉換為 json 格式。但在這之前，應該考慮，access.log 和 error.log 是兩種不同的格式，不能用同一種方式去匹配。那怎么判斷數據是來自 access.log 還是 error.log 呢？

這里語法肯定是想到了：

If … {
Access.log
} elseif … {
Error.log
}

對，語法沒錯，但是用什么條件呢？查看上面的日志，不難發現每次都有這樣的字段：

Access.log 日志數據：
            "fileset" => {
        "module" => "nginx",
          "name" => "access"

error.log 日志數據：
       "fileset" => {
        "module" => "nginx",
          "name" => "error"

這樣，就有判斷的依據了，根據logstash配置語法開始寫：

到目前為止，logstash 的 nginx 日志收集過濾配置文件如下：

配置文件名：nginx.conf

input {
    beats {
        port => "5044"    
    }    
}

filter {
    if [fileset][name] == "access" {
        json {
            source => "message"
            remove_field => "message"
            remove_field => "@timestamp"
        }
        date {
            match => ["time_local", "ISO8601"]
            target => "@timestamp"
        }
        grok {
            match => { "request" => "%{WORD:method} (?<url>.* )" }
        }
        mutate {
            remove_field => ["host","event","input","request","offset","prospector","source","type","tags","beat"]
            rename => {"http_user_agent" => "agent"}
            rename => {"upstream_response_time" => "response_time"}
            rename => {"http_x_forwarded_for" => "x_forwarded_for"}
            split => {"x_forwarded_for" => ", "}
            split => {"response_time" => ", "}
        }
        geoip {
            source => "real_ip"
        }
    }
    if [fileset][name] == "error" {
        mutate {
            remove_field => ["@timestamp"]
        }
        grok {
            match => {"message" => "(?<datetime>%{YEAR}[./-]%{MONTHNUM}[./-]%{MONTHDAY}[- ]%{TIME}) \[%{LOGLEVEL:severity}\] %{POSINT:pid}#%{NUMBER}: %{GREEDYDATA:errormessage}(?:, client: (?<real_ip>%{IP}|%{HOSTNAME}))(?:, server: %{IPORHOST:domain}?)(?:, request: %{QS:request})?(?:, upstream: (?<upstream>\"%{URI}\"|%{QS}))?(?:, host: %{QS:request_host})?(?:, referrer: \"%{URI:referrer}\")?"}
        }
        date {
            match => ["datetime", "yyyy/MM/dd HH:mm:ss"]
            target => "@timestamp"
        }
        mutate {
            remove_field => ["message","request","http_referer","host","event","input","offset","prospector","source","type","tags","beat"]
        }
    }
}

output {
    stdout {
        codec => "rubydebug"        
    }
}

nginx.conf

測試 access.log 日志格式數據：

{
           "@version" => "1",
              "agent" => "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36",
             "domain" => "localhost",
       "request_body" => "-",
                "log" => {
        "file" => {
            "path" => "/www/log/access.log"
        }
    },
       "http_referer" => "-",
      "response_time" => [
        [0] "-"
    ],
            "real_ip" => "",
            "fileset" => {
        "module" => "nginx",
          "name" => "access"
    },
    "upstream_status" => "-",
    "body_bytes_sent" => "0",
             "status" => 304,
         "@timestamp" => 2019-09-14T07:39:50.000Z,
         "time_local" => "2019-09-14T15:39:50+08:00",
       "request_time" => "0.000",
      "upstream_addr" => "-",
    "x_forwarded_for" => [
        [0] "-"
    ],
            "request" => "GET / HTTP/1.1"
}

logstash 輸出內容

測試 error.log 日志格式數據：

{
           "@version" => "1",
              "agent" => "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36",
             "domain" => "localhost",
       "request_body" => "-",
                "log" => {
        "file" => {
            "path" => "/www/log/access.log"
        }
    },
       "http_referer" => "-",
      "response_time" => [
        [0] "-"
    ],
            "real_ip" => "",
            "fileset" => {
        "module" => "nginx",
          "name" => "access"
    },
    "upstream_status" => "-",
    "body_bytes_sent" => "571",
             "status" => 404,
         "@timestamp" => 2019-09-14T07:41:48.000Z,
         "time_local" => "2019-09-14T15:41:48+08:00",
       "request_time" => "0.000",
      "upstream_addr" => "-",
    "x_forwarded_for" => [
        [0] "-"
    ],
            "request" => "GET /123.html HTTP/1.1"
}

logstash 輸出內容

這下沒問題了，兩種格式的數據都獲取到了。接下來就將數據寫入到 elasticsearch中。

到目前為止，logstash 配置文件 nginx.conf 如下：

input {
    beats {
        port => "5044"    
    }    
}

filter {
    if [fileset][name] == "access" {
        json {
            source => "message"
            remove_field => "message"
            remove_field => "@timestamp"
        }
        date {
            match => ["time_local", "ISO8601"]
            target => "@timestamp"
        }
        grok {
            match => { "request" => "%{WORD:method} (?<url>.* )" }
        }
        mutate {
            remove_field => ["host","event","input","request","offset","prospector","source","type","tags","beat"]
            rename => {"http_user_agent" => "agent"}
            rename => {"upstream_response_time" => "response_time"}
            rename => {"http_x_forwarded_for" => "x_forwarded_for"}
            split => {"x_forwarded_for" => ", "}
            split => {"response_time" => ", "}
        }
        geoip {
            source => "real_ip"
        }
    }
    if [fileset][name] == "error" {
        mutate {
            remove_field => ["@timestamp"]
        }
        grok {
            match => {"message" => "(?<datetime>%{YEAR}[./-]%{MONTHNUM}[./-]%{MONTHDAY}[- ]%{TIME}) \[%{LOGLEVEL:severity}\] %{POSINT:pid}#%{NUMBER}: %{GREEDYDATA:errormessage}(?:, client: (?<real_ip>%{IP}|%{HOSTNAME}))(?:, server: %{IPORHOST:domain}?)(?:, request: %{QS:request})?(?:, upstream: (?<upstream>\"%{URI}\"|%{QS}))?(?:, host: %{QS:request_host})?(?:, referrer: \"%{URI:referrer}\")?"}
        }
        date {
            match => ["datetime", "yyyy/MM/dd HH:mm:ss"]
            target => "@timestamp"
        }
        mutate {
            remove_field => ["message","request","http_referer","host","event","input","offset","prospector","source","type","tags","beat"]
        }
    }
}

#output {
#    stdout {
#        codec => "rubydebug"        
#    }
#}
output {
    elasticsearch {
        hosts => ["192.168.118.14"]
        index => "logstash-nginx-%{+YYYY.MM.dd}"
    }
}