Telegraf

Installation

• Install Telegraf | Telegraf 1.26 Documentation (influxdata.com)

RHEL

cat <<EOF | sudo tee /etc/yum.repos.d/influxdb.repo
[influxdb]
name = InfluxData Repository - Stable
baseurl = https://repos.influxdata.com/stable/\$basearch/main
enabled = 1
gpgcheck = 1
gpgkey = https://repos.influxdata.com/influxdata-archive_compat.key
EOF

sudo yum install telegraf

Ubuntu/Debian

curl -s https://repos.influxdata.com/influxdata-archive_compat.key > influxdata-archive_compat.key
echo '393e8779c89ac8d958f81f942f9ad7fb82a25e133faddaf92e15b16e6ac9ce4c influxdata-archive_compat.key' | sha256sum -c && cat influxdata-archive_compat.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/influxdata-archive_compat.gpg > /dev/null
echo 'deb [signed-by=/etc/apt/trusted.gpg.d/influxdata-archive_compat.gpg] https://repos.influxdata.com/debian stable main' | sudo tee /etc/apt/sources.list.d/influxdata.list
sudo apt-get update && sudo apt-get install telegraf

Configuration

telegraf config > telegraf.conf

Outputs.InfluxDB v1

###############################################################################
#                            OUTPUT PLUGINS                                   #
###############################################################################


# Configuration for sending metrics to InfluxDB
[[outputs.influxdb]]
  urls = ["http://influxdb.server.ip.addr:8086"]
  database = "db-name"
  timeout = "0s"
  username = "db-user"
  password = "db-pass"

Outputs.InfluxDB v2

###############################################################################
#                            OUTPUT PLUGINS                                   #
###############################################################################

[[outputs.influxdb_v2]]
  urls = ["http://influxdb.server.ip.addr:8086"]
  token = "example-token"
  organization = "example-org"
  bucket = "example-bucket"

Inputs.exec

data_format = "influx"

文字資料格式：

# Format
measurement,tag1=val1,tag2=val2<whitespace>field1="v1",field2=1<whitespace>0000000000000000000
# Sample data
airsensors,location=bedroom,sensor_id=mi0201 temperature=19.1,humidity=85,battery=78

• 0000000000000 欄位 Timestamp 是選擇性，如空白，預設是 InfluxDB 主機系統時間(UTC)。
• 詳細教學：Line protocol | InfluxDB OSS v2 Documentation (influxdata.com)

Scripts

Samples #1

#/bin/bash

devname=(`lsblk| grep 'disk'|awk '{print $1}'`)
dirname=(`lsblk| grep 'disk'|awk '{if ($7=="") print "/";else print $7}'`)
#At that time, I wanted to store these directory names in dictionary format, and later changed to variable mode, shell Of[ ] { } * @ $Special characters will drive you crazy
#declare -A devdict
devnum=`expr ${#devname[@]} - 1`
for i in `seq 0 $devnum`;do
  if [-z "${dirname[$i]}" ];then
    eval ${devname[$i]}="/"
  else
    eval ${devname[$i]}="${dirname[$i]}"
  fi
  #devdict+=([${devname[$i]}]="${dirname[$i]}")
done
#echo ${!devdict[*]}
#echo ${devdict[*]}

ioarry=`iostat -x | grep sd|awk '{print "datadir=${"$1"}@r="$4",w="$5",await="$10",svctm="$11",util="$12}'`
for i in ${ioarry[@]};do
  eval temp="${i}"
  #Replace the special character @, and the space in the shell will be truncated to two elements
  temp=${temp/@/ }
  echo "exec,${temp}"
  #Ensure that the final output is in the following format. The first character is the measurement name. If the input.exec plug-in has the configuration name "suffix", the suffix will be added automatically
  #The output format is measurement name, comma, tag keys (comma separated), space, filed keys (comma separated)
  #The data format output mismatch will lead to the failure of telegraf to parse the data and go to the influxdb. It took a long time to debug and didn't look at the hole dug by the official website 
  #exec,datadir=/data/data11 r=4.1,w=6.1,await=0.83,svctm=1.35,util=1.46" 
done 
#echo ${devdict[@]}

[[inputs.exec]]
  ##Commands array
  commands = ["bash /appcom/telegraf/collect_iostat.sh",]
  timeout='5s'
  ##Suffix for measurements
  name_suffix="_collectiostat"
  data_format="influx"

Sample #2

#!/bin/sh
hostname=`hostname`
uptime=`awk '{print $1}' /proc/uptime`
if uptime |grep -q user ; then
load1=`uptime | grep -ohe 'up .*' | sed 's/,//g' | awk '{ print $7}'`
load5=`uptime | grep -ohe 'up .*' | sed 's/,//g' | awk '{ print $8}'`
load15=`uptime | grep -ohe 'up .*' | sed 's/,//g' | awk '{ print $9}'`
else
load1=`uptime | grep -ohe 'up .*' | sed 's/,//g' | awk '{ print $5}'`
load5=`uptime | grep -ohe 'up .*' | sed 's/,//g' | awk '{ print $6}'`
load15=`uptime | grep -ohe 'up .*' | sed 's/,//g' | awk '{ print $7}'`
fi
echo "uptime,host=$hostname uptime=$uptime,load1=$load1,load5=$load5,load15=$load15"

[agent]
interval = "5s"
round_interval = true
[[inputs.swap]]
  [inputs.swap.tags]
    metrics_source="telegraf_demo"
[[inputs.exec]]
  commands = ["/etc/telegraf/uptime.sh"]
  data_format = "influx"
  [inputs.exec.tags]
    metrics_source="telegraf_demo"
[[outputs.influxdb]]
  url = "https://influxdemo:8086"
  database = "telegraf"

Sample #3

#! /bin/bash
/usr/bin/speedtest --format json | jq '.download.bandwidth = .download.bandwidth / 125000 |  .upload.bandwidth = .upload.bandwidth / 125000'

[[inputs.exec]]
  commands = [
    "/home/rock64/speedtest.sh"
    ]
  interval = "300s"
  timeout = "60s"

Sample #4

[[inputs.exec]]
  commands = ["sh -c 'sysctl -n dev.cpu.0.temperature | tr -d C'"]
  name_override = "cpu_temp"
  timeout = "5s"
  data_format = "value"
  data_type = "float"
  [inputs.exec.tags]
    core = "core0"

[[inputs.exec]]
  commands = ["sh -c 'sysctl -n dev.cpu.1.temperature | tr -d C'"]
  name_override = "cpu_temp"
  timeout = "5s"
  data_format = "value"
  data_type = "float"
  [inputs.exec.tags]
    core = "core1"

[[inputs.exec]]
  commands = ["sh -c 'sysctl -n dev.cpu.2.temperature | tr -d C'"]
  name_override = "cpu_temp"
  timeout = "5s"
  data_format = "value"
  data_type = "float"
  [inputs.exec.tags]
    core = "core2"

[[inputs.exec]]
  commands = ["sh -c 'sysctl -n dev.cpu.3.temperature | tr -d C'"]
  name_override = "cpu_temp"
  timeout = "5s"
  data_format = "value"
  data_type = "float"
  [inputs.exec.tags]
    core = "core3"

Q & A

[agent] Error terminating process: operation not permitted

Causation: 在 telegraf.conf 設定裡，有個 agent 排程啟動時，因為 timeout 設定時間已到，而 agent 還未完成工作，telegraf 嘗試終止該 agent 失敗。

Solution: 解決方法一：如果無所謂終止 agent 失敗的行為，可以將 timeout 時間調大，就可以避免或降低錯誤的發生。

解決方法二：如果想利用 timeout 的設定來避免 agent 可能因為某些異常造成大量程序累積，進而影響系統的運作。

分析 telegraf 無法終止 agent 的原因，排除異常後，在依需要調整 timeout 時間。

以筆者案例，agent 使用 sudo 指令收集 db2 的效能指標，指令如下

[[inputs.exec]]
    interval = "1h"
    commands = ["sudo -u db2mon sh -c '/home/db2mon/bin/collect_db2x1h.sh -d centdb -a b_centdb'"]
    timeout = "5s"
    data_format = "influx"

由於 telegraf 無法 kill 用 sudo 執行的其他帳號下的程序，解決方法是修改指令 collect_db2x1h.sh，可以讓 telegraf 不用 sudo 就可以執行。 

[[inputs.exec]]
    interval = "1h"
    commands = ["/home/db2mon/bin/collect_db2x1h.sh -d centdb -a b_centdb"]
    timeout = "15s"
    data_format = "influx"

驗證一下，timeout 時間到達能否成功終止 agent，如果有，會顯示下方訊息：

[inputs.exec] Error in plugin: exec: command timed out for command '/home/db2mon/bin/collect_db2x1h.sh -d centdb -a b_centdb'

沒問題後，再調整合適的 timeout。

Error in plugin: metric parse error: expected tag at 7:20:

Causation: 輸出的 Influxdata 資料格式不正確

Solution: 檢查第 7 筆的第 20 個字元。Influxdada 格式為

measurement, tag-key1=tag-value1,tag-key2=tag-value2 field-key1=field-value1,field-key2=field-value2,....

• tag-key type: string
• tag-value type: string
  NOTE: 雙引號不是必要的
• field-key type: string
• field-value type: Float | Integer | UInteger | String | Boolean
  NOTE: 如果是 string 必須用雙引號

max-series-per-database limit exceeded: (1000000)

Causation: 寫入的資料庫已經達到設定的上限總筆數 1000000。

在 InfluxDB CLI 執行這段，檢查目前資料庫的筆數

show series cardinality on <db-name>

Solution: 調整 InfluxDB 主機上的設定，編輯 /etc/influxdb/influxdb.conf 預設是 1000000

# max-series-per-database = 1000000
max-series-per-database = 2000000

重啟 InfluxDB

systemctl restart influxdb