一、背景
假设我有2种类型的服务器，一种是本地电脑(每个指标名称都存在{nodename='mac-local'})，一种是阿里云服务器(每个指标名称都存在{nodename='aliyun'})，同时每个指标下都存在一个 {instance='具体的服务器的ip地址'}标签。
即我们采集的时间序列大致上都有如下标签：
eg: node_uname_info{nodename='xxxx',instance='yyyy'}
二、需求
我们想监控一下每台主机的cpu的使用情况。同时不能在一个图形上显示出所有的机器的cpu使用率，需要根据用户的选择而显示。即要出现下图所示的结果，这个情况我们可以通过grafana的模板变量来实现。
从上图可以，instance的出现是根据 服务器类型 的选择而不同的。
三、实现步骤
1、创建一个Dashboard
2、设置模板变量
1、在Dashboard页面点击小齿轮⚙️图标。 
2、点击创建一个变量
1、添加 nodename 变量，获取服务器的类型
2、添加 instance 变量。
注意： instance变量的值是根据上一步 nodename 变量的值而来的，及选择不同的 nodename，instance 的值应该是不同的。及在 instance 变量的查询语句中需要引用 nodename 变的值，通过 $nodename 即可引用。
做完上方出现的1，2两步，即可出现需求中出现的画面。
3、创建一个图表，监控一下 cpu 的使用率
四、上方例子的完成json字符串
在 grafana 中引入此json串，即可实现上图的效果。但是要保证每个时间序列都存在 nodename 和 instance的标签。
{
"annotations": {
"list": [
{
"builtIn": 1,
"datasource": "-- Grafana --",
"enable": true,
"hide": true,
"iconColor": "rgba(0, 211, 255, 1)",
"name": "Annotations & Alerts",
"type": "dashboard"
}
]
},
"editable": true,
"gnetId": null,
"graphTooltip": 0,
"id": 3,
"iteration": 1616217012533,
"links": [],
"panels": [
{
"aliasColors": {},
"bars": false,
"dashLength": 10,
"dashes": false,
"datasource": null,
"decimals": 2,
"description": "",
"fieldConfig": {
"defaults": {
"custom": {},
"unit": "percent"
},
"overrides": []
},
"fill": 1,
"fillGradient": 0,
"gridPos": {
"h": 8,
"w": 24,
"x": 0,
"y": 0
},
"hiddenSeries": false,
"id": 2,
"legend": {
"alignAsTable": true,
"avg": true,
"current": true,
"max": true,
"min": true,
"rightSide": true,
"show": true,
"total": false,
"values": true
},
"lines": true,
"linewidth": 1,
"nullPointMode": "null",
"options": {
"alertThreshold": true
},
"percentage": false,
"pluginVersion": "7.4.3",
"pointradius": 2,
"points": true,
"renderer": "flot",
"seriesOverrides": [],
"spaceLength": 10,
"stack": false,
"steppedLine": false,
"targets": [
{
"expr": "(1 - avg(irate(node_cpu_seconds_total{mode='idle',nodename=~\"$nodename\",instance=~\"$instance\"}[5m])) by (instance)) * 100",
"interval": "",
"legendFormat": "{{instance}} CPU使用率",
"refId": "A"
}
],
"thresholds": [],
"timeFrom": null,
"timeRegions": [],
"timeShift": null,
"title": "$instance CPU使用率",
"tooltip": {
"shared": true,
"sort": 0,
"value_type": "individual"
},
"type": "graph",
"xaxis": {
"buckets": null,
"mode": "time",
"name": null,
"show": true,
"values": []
},
"yaxes": [
{
"$$hashKey": "object:231",
"format": "percent",
"label": null,
"logBase": 1,
"max": null,
"min": null,
"show": true
},
{
"$$hashKey": "object:232",
"format": "short",
"label": null,
"logBase": 1,
"max": null,
"min": null,
"show": true
}
],
"yaxis": {
"align": false,
"alignLevel": null
}
}
],
"schemaVersion": 27,
"style": "dark",
"tags": [],
"templating": {
"list": [
{
"allValue": null,
"current": {
"selected": true,
"tags": [],
"text": [
"mac-local"
],
"value": [
"mac-local"
]
},
"datasource": null,
"definition": "label_values(node_uname_info{nodename=~\".*\"},nodename)",
"description": null,
"error": null,
"hide": 0,
"includeAll": false,
"label": "服务器类型",
"multi": true,
"name": "nodename",
"options": [
{
"selected": false,
"text": "aliyun",
"value": "aliyun"
},
{
"selected": true,
"text": "mac-local",
"value": "mac-local"
}
],
"query": {
"query": "label_values(node_uname_info{nodename=~\".*\"},nodename)",
"refId": "StandardVariableQuery"
},
"refresh": 0,
"regex": "",
"skipUrlSync": false,
"sort": 0,
"tagValuesQuery": "",
"tags": [],
"tagsQuery": "",
"type": "query",
"useTags": false
},
{
"allValue": null,
"current": {
"selected": true,
"text": [
"localhost:9081"
],
"value": [
"localhost:9081"
]
},
"datasource": null,
"definition": "label_values(node_uname_info{nodename=~\"$nodename\",instance=~\".*\"},instance)",
"description": null,
"error": null,
"hide": 0,
"includeAll": false,
"label": null,
"multi": true,
"name": "instance",
"options": [
{
"selected": true,
"text": "localhost:9081",
"value": "localhost:9081"
}
],
"query": {
"query": "label_values(node_uname_info{nodename=~\"$nodename\",instance=~\".*\"},instance)",
"refId": "StandardVariableQuery"
},
"refresh": 0,
"regex": "",
"skipUrlSync": false,
"sort": 0,
"tagValuesQuery": "",
"tags": [],
"tagsQuery": "",
"type": "query",
"useTags": false
}
]
},
"time": {
"from": "now-5m",
"to": "now"
},
"timepicker": {},
"timezone": "",
"title": "测试模板变量",
"uid": "Umb3YDQMz",
"version": 6
}