collectd 的數據如何映射到influxdb

collectd 的數據如何映射到influxdb

本文將使用collectdctl 向influxdb 發送數據， 同時介紹collectd 的數據是如何映射到influxdb 中（建立measurements,series）

1. 配置influxdb

   [[collectd]]
     enabled = true
     bind-address = "127.0.0.1:25826"
     database = "collectd"
     retention-policy = ""
     # typesdb 
     typesdb = "/usr/local/Cellar/collectd/5.8.0/share/collectd/types.db"

2. 配置collected

   LoadPlugin cpu
     LoadPlugin memory
     LoadPlugin network
     LoadPlugin unixsock
     <Plugin network>
             <Server "127.0.0.1" "25826">
             </Server>
     </Plugin>

3. 查看influxdb 確認collectd push 數據

4. collectdctl listval

   localhost/load/load
     localhost/memory/memory-active
     localhost/memory/memory-free
     localhost/memory/memory-inactive
     localhost/memory/memory-wired
     localhost/interface-en0/if_errors
     localhost/interface-en0/if_octets

5. influx -database 'collectd' -execute 'show series'

   load_longterm,host=localhost,type=load
    load_midterm,host=localhost,type=load
    load_shortterm,host=localhost,type=load
    memory_value,host=localhost,type=memory,type_instance=active
    memory_value,host=localhost,type=memory,type_instance=free
    memory_value,host=localhost,type=memory,type_instance=inactive
    memory_value,host=localhost,type=memory,type_instance=wired
    interface_rx,host=localhost,instance=en0,type=if_errors
    interface_rx,host=localhost,instance=en0,type=if_octets
    interface_tx,host=localhost,instance=en0,type=if_errors
    interface_tx,host=localhost,instance=en0,type=if_octets

6. cat /usr/local/Cellar/collectd/5.8.0/share/collectd/types.db

   load                    shortterm:GAUGE:0:5000, midterm:GAUGE:0:5000, longterm:GAUGE:0:5000
     memory                  value:GAUGE:0:281474976710656
     if_errors               rx:DERIVE:0:U, tx:DERIVE:0:U
     if_octets               rx:DERIVE:0:U, tx:DERIVE:0:U

7. collectdb 用identifier 來描述一條數據，identifier至關與KV數據庫的Key。
   identifier 格式以下
   [<hostname>/]<plugin>[-<plugin_instance>]/<type>[-<type_instance>]

   collectdb用types.db的映射關係來描述Value 的格式
   identifier 的type 必定要在types.db中 找到不然報錯

   1. localhost/load/load 
      type:load  
      types.db 定義
      load shortterm:GAUGE:0:5000, midterm:GAUGE:0:5000, longterm:GAUGE:0:5000
      
    2. localhost/interface-en0/if_octets
      type: if_octets
      types.db  定義
      if_octets               rx:DERIVE:0:U, tx:DERIVE:0:U 
    3. localhost/memory/memory-free
       type: memory (free 並非type)
       memory                  value:GAUGE:0:281474976710656

8.  其實經過4，5，6 的數據咱們很容易看數collectd 到influxdb的映射關係

1. localhost/load/load
   plugin: load
   type: load
   typeValue: shortterm, midterm, longterm
   映射到influxdb
   measurements: load_shortterm load_midterm load_longterm
   tags:  host=localhost,type=load
 2. localhost/memory/memory-active
    plugin: memory
    type: memory
    typeValue: Value
    映射到influxdb
    measurements: memory_value
    tags: host=localhost,type=memory,type_instance=active
 3. localhost/interface-en0/if_octets
    plugin: interface
    type: if_octets
    typeValue: rx, tx
    measurements: interface_rx, interface_tx
    tags: host=localhost,instance=en0,type=if_octets

9.  collectd 的 identifier
 [<hostname>/]<plugin>[-<plugin_instance>]/<type>[-<type_instance>]
 
 的`plugin_typeValue`構成了influxdb的measurements
 tags：hostname=<hostname>， instance=<plugin_instance>, type=<type>, type_instance=<type_instance>
 
 因爲 plugin_instance , type_instace 是可選的
 因此collectd 倒入influxdb的數據tags 至少由hostname， type
 

 
10. 練習

1. collectdctl putval localhost/xxx/load N:111
     influxdb 會新建xxx_longterm, xxx_shortterm, xxx_midterm measurement
     tag hostname=localhost,type=load
  2. collectdctl putval localhost/xxx/if_octets N:1:100
    influxdb 會新建xxx_rx, xxx_tx measurement
  3.echo "test    running:GAUGE:0:U" >> /usr/local/Cellar/collectd/5.8.0/share/collectd/types.db
    collectdct putval localhost xxx/test N:1000
    influxdb 會新建xxx_test measurement
```