每天一点基础K8S--prometheus基础

prometheus基础

1、简介

1、开源的系统监控和告警系统
Prometheus is an open-source systems monitoring and alerting toolkit

官网：https://prometheus.io/docs/introduction/overview/

2、prometheus架构图

简单理解一下，prometheus架构中主要包括：prometheus server、exporter、pushgateway、alertmanager、grafana

其中，prometheus server主要包括：
  1、retrieval，负载在活跃的target主机上主机相应数据；
  2、tsdb，存储采集的信息；
  3、http server，接受查询的模块；

3、主要特征

1、以时间为序列的，以度量名称和相应的key-value构建的多维度数据模型；
a multi-dimensional data model with time series data identified by metric name and key/value pairs

2、promQL语言灵活；
PromQL, a flexible query language to leverage this dimensionality

3、可以依靠本地本地存储实现；
no reliance on distributed storage; single server nodes are autonomous

4、依靠HTTP协议，通过pull的方式时间序列上的变化；
time series collection happens via a pull model over HTTP

5、可以通过pushgateway实现数据采集；
pushing time series is supported via an intermediary gateway

6、可以通过服务发现或者静态配置来发现目标target；
targets are discovered via service discovery or static configuration

7、图形界面多样化；
multiple modes of graphing and dashboarding support

4、基本概念

4.1、数据模型（data model）

#以时间序列为基础，同一条数据流需要有相同的度量值（metric）和相同的标签（labels）
Prometheus fundamentally stores all data as time series: streams of timestamped values belonging to the same metric and the same set of labeled dimensions. 

# 那么，时间戳 + metric + label = 样本

# natotion语法
<metric name>{<label name>=<label value>, ...}

4.2、度量类型/数据类型（metric type）

# counter 计数器
# 累积的数值，只能增加，或者重置为0，常用于统计服务器请求总数、任务完成数等；
A counter is a cumulative metric that represents a single monotonically increasing counter whose value can only increase or be reset to zero on restart. For example, you can use a counter to represent the number of requests served, tasks completed, or errors.


# gauge 测量器
# 可增可减，常用于监控温度、内存、CPU使用情况；
A gauge is a metric that represents a single numerical value that can arbitrarily go up and down.


# Histogram 柱状图
# 统计、计算桶内的的样本情况
A histogram samples observations (usually things like request durations or response sizes) and counts them in configurable buckets.


# summary 统计图
# 与柱状图类似，可用于统计总数，
Similar to a histogram, a summary samples observations (usually things like request durations and response sizes). While it also provides a total count of observations and a sum of all observed values, it calculates configurable quantiles over a sliding time window.

4.3、jobs and instances

# 实例，instance
# 在prometheus环境中，可以被查询请求的一个端点均可称为一个instance。
# 为某一需求而采集的instance集合称为jobs，
In Prometheus terms, an endpoint you can scrape is called an instance, usually corresponding to a single process. A collection of instances with the same purpose, a process replicated for scalability or reliability for example, is called a job.
For example, an API server job with four replicated instances:

job: api-server
instance 1: 1.2.3.4:5670
instance 2: 1.2.3.4:5671
instance 3: 5.6.7.8:5670
instance 4: 5.6.7.8:5671

5、prometheus的配置文件

配置文件可以查看官网：https://prometheus.io/docs/prometheus/latest/configuration/configuration/