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Configure kube-dns to expose metrics #2566

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Jun 14, 2018
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Configure kube-dns to expose metrics #2566

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8 changes: 8 additions & 0 deletions parts/k8s/addons/kubernetesmasteraddons-kube-dns-deployment.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,8 @@ spec:
metadata:
annotations:
scheduler.alpha.kubernetes.io/critical-pod: ""
prometheus.io/scrape: "true"
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Should these annotations be on the service rather than the deployment?

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Each pods has its own set of stats so Prometheus should scrape each pods, not the service.

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I believe the recommended approach is to annotate the service (though I cannot find a black and white statement from the team about it now). The pods of the service will still get scraped if using a role of endpoints in the kubernetes_sd_configs.
The exposed metrics will be the same either way, but there are a bunch of extra labels available this way.

Also, do note that this annotation is not really standardized, even if it is common in examples. We do not use it at all, and rather use ServiceMonitors from the prometheus-operator. But perhaps it is a reasonable default to ship anyway? Is it set on other kube* things with metrics in acs-engine?

prometheus.io/port: "10055"
labels:
k8s-app: kube-dns
kubernetes.io/cluster-service: "true"
Expand Down Expand Up @@ -78,6 +80,9 @@ spec:
- "--dns-port=10053"
- "--v=2"
- "--config-dir=/kube-dns-config"
env:
- name: PROMETHEUS_PORT
value: "10055"
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Is this port fixed? Can you please point me at the docs for this?

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It's not fixed, we could define any port not already used but that's what they use in kubernetes example:

https://github.com/kubernetes/kubernetes/blob/master/cluster/addons/dns/kube-dns.yaml.base#L132-L134

image: <kubernetesKubeDNSSpec>
livenessProbe:
failureThreshold: 5
Expand All @@ -96,6 +101,9 @@ spec:
- containerPort: 10053
name: dns-tcp-local
protocol: TCP
- containerPort: 10055
name: metrics
protocol: TCP
readinessProbe:
httpGet:
path: "/readiness"
Expand Down