普罗米修斯字符串匹配查询语法：
=: Select labels that are exactly equal to the provided string.
!=: Select labels that are not equal to the provided string.
=~: Select labels that regex-match the provided string.
!~: Select labels that do not regex-match the provided string.
具体可以看这里：
https://prometheus.io/docs/prometheus/latest/querying/basics/
