prometheus抓取保护配置以防止压力过载

场景

担心您的应用程序指标可能突然激增，以及指标突然激增导致prometheus压力过载

就像生活中的许多事情一样，标签要有节制。当带有用户 ID 或电子邮件地址的标签被添加到指标时，虽然它不太可能结束，因为突然之间，您的一个目标可能会在每次抓取时抽出数十万个时间序列，从而导致 Prometheus 出现性能问题。

设置scrap抓取指标过载保护

sample_limit 是一个抓取配置字段，如果返回的时间序列超过给定数量，它将导致抓取失败。默认情况下禁用。例如：

scrape_configs:- job_name: 'my_job'sample_limit: 5000static_configs:- targets:- my_target:1234

如果返回的时间序列超过 5000 个，将导致目标的抓取失败，将 up 设置为 0，就好像目标已关闭一样。从那里，您可以在抓取时使用普罗米修斯删除指标来删除有问题的指标，同时等待应用程序被修复。也就是说metric_relabel_configs在sample_limit之前应用。

各类过载保护汇总

• sample_limit

# Per-scrape limit on number of scraped samples that will be accepted.
# If more than this number of samples are present after metric relabeling
# the entire scrape will be treated as failed. 0 means no limit.
[ sample_limit: <int> | default = 0 ]

• body_size_limit:

# An uncompressed response body larger than this many bytes will cause the
# scrape to fail. 0 means no limit. Example: 100MB.
# This is an experimental feature, this behaviour could
# change or be removed in the future.
[ body_size_limit: <size> | default = 0 ]

• label_limit

# Per-scrape limit on number of labels that will be accepted for a sample. If
# more than this number of labels are present post metric-relabeling, the
# entire scrape will be treated as failed. 0 means no limit.
[ label_limit: <int> | default = 0 ]

• label_name_length_limit

# Per-scrape limit on length of labels name that will be accepted for a sample.
# If a label name is longer than this number post metric-relabeling, the entire
# scrape will be treated as failed. 0 means no limit.
[ label_name_length_limit: <int> | default = 0 ]

• label_value_length_limit

# Per-scrape limit on length of labels value that will be accepted for a sample.
# If a label value is longer than this number post metric-relabeling, the
# entire scrape will be treated as failed. 0 means no limit.
[ label_value_length_limit: <int> | default = 0 ]

• target_limit

# Per-scrape config limit on number of unique targets that will be
# accepted. If more than this number of targets are present after target
# relabeling, Prometheus will mark the targets as failed without scraping them.
# 0 means no limit. This is an experimental feature, this behaviour could
# change in the future.
[ target_limit: <int> | default = 0 ]