如果victoriametrics的scrape_timeout大于scrape_interval时会怎么样

背景

我们在配置采集的时候，有时候会不小心配置了scrape_timeout大于scrape_interval，那么这时会出现什么情况呢？vmagent在采集的时候，如果上一次采集还没有完成，其实会结束掉再发起下一次采集的，不会出现说上一次没完成，又发起新的一次，因为这样只会采集越堆积越多，在到了下一次还没有完成或者超过了scrape_timeout，那么就会标识采集失败

如果出现scrape_config的scrape_timeout大于scrape_interval时会怎么样

官方文档的说明

https://docs.victoriametrics.com/sd_configs.html#scrape_configs

  # scrape_timeout is an optional timeout when scraping the targets.# By default, the scrape_timeout specified in `global` section is used.# See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#configuration-file# If `global` section doesn't contain the `scrape_timeout` option,# then 10 seconds interval is used.# Example values:# - "30s" - 30 seconds# - "2m" - 2 minutes# The `scrape_timeout` cannot exceed the `scrape_interval`.# The scrape_timeout can be set on a per-target basis by specifying `__scrape_timeout__`# label during target relabeling phase.# See https://docs.victoriametrics.com/vmagent.html#relabeling# scrape_timeout: <duration>

源码里的处理

// ScrapeConfigs returns the scrape configurations.
func (c *Config) GetScrapeConfigs() ([]*ScrapeConfig, error) {scfgs := make([]*ScrapeConfig, len(c.ScrapeConfigs))jobNames := map[string]string{}for i, scfg := range c.ScrapeConfigs {// We do these checks for library users that would not call Validate in// Unmarshal.if err := scfg.Validate(c.GlobalConfig.ScrapeInterval, c.GlobalConfig.ScrapeTimeout); err != nil {return nil, err}......
}func (c *ScrapeConfig) Validate(defaultInterval, defaultTimeout model.Duration) error {if c == nil {return errors.New("empty or null scrape config section")}// First set the correct scrape interval, then check that the timeout// (inferred or explicit) is not greater than that.if c.ScrapeInterval == 0 {c.ScrapeInterval = defaultInterval}if c.ScrapeTimeout > c.ScrapeInterval {return fmt.Errorf("scrape timeout greater than scrape interval for scrape config with job name %q", c.JobName)}if c.ScrapeTimeout == 0 {if defaultTimeout > c.ScrapeInterval {c.ScrapeTimeout = c.ScrapeInterval} else {c.ScrapeTimeout = defaultTimeout}}return nil
}

结论：

• job的scrape_timeout如果大于scrape_interval则报错
• 如果全局的scrape_timeout大于采集的scrape_interval，则将scrape_timeout设置为scrape_interval，否则设置job的scrape_interval为全局scrape_interval