How to get a pod's labels in Prometheus when pulling the metrics from Kube State Metrics

10/25/2018

I have a Prometheus pod running along with my Kube-State-Metrics (KSM) pod. The KSM collects all the metrics from all the pods across all the namespaces in the cluster. Prometheus simply scrapes the metrics from KSM - this way Prometheus doesn't need to scrape the individual pods.

When pods are deployed, their deployment has certain pod-related labels as shown below. They have two important labels: APP and TEAM:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    APP: AppABC
    TEAM: TeamABC
...

Within Prometheus, my scrape configuration looks like this:

scrape_configs:
  - job_name: 'pod monitoring'
    honor_labels: true
    kubernetes_sd_configs:
    - role: pod
    relabel_configs:
    - action: labelmap
      regex: __meta_kubernetes_pod_label_(.+)
...

Problem is, when Prometheus scrapes the information from kube-state-metrics, it overwrites the APP with kube-state-metrics. e.g. this metric below is actually for an app called "AppABC", yet Prometheus overwrote the app label to kube-state-metrics.

kube_pod_container_status_restarts_total{
    app="kube-state-metrics",
    container="appabccontainer",
    job="pod monitoring",
    namespace="test-namespace",
    pod="appabc-766cbcb68d-29smr"
}

Is there anyway for me to scrape the metrics from kube-state-metrics BUT keep the APP and TEAM labels together without overwriting them?

EDIT - I figured it out

My Issue: My deployment and pods have certain labels defined (APP, TEAM). Kube-state-metrics gets these from K8 API. When Prometheus scrapes from kube-state-metrics, it doesn't have those labels.

My Objective: Expose those labels into Prometheus.

My Solution: Using PromQL you can do group by. So in my prometheus-rules.yaml, I changed this:

expr: kube_pod_status_phase{phase="Failed"} > 0

to this:

expr: kube_pod_status_phase{phase="Failed"} * on (pod,namespace) group_right kube_pod_labels > 0

So my new alert rule looks like this:

- name: Pod_Failed
  rules:
  - alert: pod_failed
    expr: kube_pod_status_phase{phase="Failed"} * on (pod,namespace) group_right kube_pod_labels > 0
    labels:
      appname: '{{ $labels.label_APP }}' # This is what I wanted to capture
      teamname: '{{ $labels.label_TEAM }}' # This is what I wanted to capture
    annotations:
      summary: 'Pod: {{ $labels.pod }} is down'
      description: 'Pod: {{ $labels.pod }} is down in {{ $labels.namespace }} namespace.'
-- BlueChips23
kubernetes
prometheus
prometheus-alertmanager

1 Answer

11/5/2018

Solution: Using PromQL you can do group by. So in my prometheus-rules.yaml, I changed this:

expr: kube_pod_status_phase{phase="Failed"} > 0

to this:

expr: kube_pod_status_phase{phase="Failed"} * on (pod,namespace) group_right kube_pod_labels > 0

So my new alert rule looks like this:

- name: Pod_Failed
  rules:
  - alert: pod_failed
    expr: kube_pod_status_phase{phase="Failed"} * on (pod,namespace) group_right kube_pod_labels > 0
    labels:
      appname: '{{ $labels.label_APP }}' # This is what I wanted to capture
      teamname: '{{ $labels.label_TEAM }}' # This is what I wanted to capture
    annotations:
      summary: 'Pod: {{ $labels.pod }} is down'
      description: 'Pod: {{ $labels.pod }} is down in {{ $labels.namespace }} namespace.'
-- Artem Golenyaev
Source: StackOverflow