PromQL中的group_left和group_right的操作函数,别离提供了Many2One和One2Many的语义,让2个不同的指标能够进行join。
残缺的语法模式:
<vector expr> <bin-op> ignoring(<label list>) group_left(<label list>) <vector expr><vector expr> <bin-op> ignoring(<label list>) group_right(<label list>) <vector expr><vector expr> <bin-op> on(<label list>) group_left(<label list>) <vector expr><vector expr> <bin-op> on(<label list>) group_right(<label list>) <vector expr>官网的demo比拟难了解,这里提供一个比拟切合实际应用的demo。
2个输出指标:
kube_pod_spec_volumes_persistentvolumeclaims_info:标识pvc和pod的挂载信息;kubelet_volume_stats_used_bytes / kubelet_volume_stats_capacity_bytes:标识pvc的使用量/总量信息;kube_pod_spec_volumes_persistentvolumeclaims_infokube_pod_spec_volumes_persistentvolumeclaims_info{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim",pod="nginx-pv-1"} 1kube_pod_spec_volumes_persistentvolumeclaims_info{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim",pod="nginx-pv-2"} 1kube_pod_spec_volumes_persistentvolumeclaims_info{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim",pod="nginx-pv-3"} 1kube_pod_spec_volumes_persistentvolumeclaims_info{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim--2",pod="busybox-xxx"} 1kube_pod_spec_volumes_persistentvolumeclaims_info{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim--2",pod="busybox-yyy"} 1kubelet_volume_stats_used_bytes / kubelet_volume_stats_capacity_bytes{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim"} 0.5{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim--2"} 0.25指标:
通过2个指标的join,失去每个pod及其挂载的pvc的使用率;答案:
kube_pod_spec_volumes_persistentvolumeclaims_info + on(namespace,persistentvolumeclaim) group_left 100*(kubelet_volume_stats_used_bytes / kubelet_volume_stats_capacity_bytes)应用group_left实现了Many2One的语义;2个指标join时,以name和persistentvolumeclaim为维度;后果:
{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim",pod="nginx-pv-1"} 50{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim",pod="nginx-pv-2"} 50{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim",pod="nginx-pv-3"} 50{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim--2",pod="busybox-xxx"} 25{__type__="gauge",instance="127.0.0.1:9999",job="pvc-test",namespace="default",persistentvolumeclaim="myclaim--2",pod="busybox-yyy"} 25参考:1.group_left/group_right官网doc:https://prometheus.io/docs/pr...2.prometheus中各种映射关系的实现:https://iximiuz.com/en/posts/...