I installed Prometheus on my Kubernetes cluster with Helm, using the community chart kube-prometheus-stack - and I get some beautiful dashboards in the bundled Grafana instance. I now wanted the recommender from the Vertical Pod Autoscaler to use Prometheus as a data source for historic metrics, as described here. Meaning, I had to make a change to the Prometheus scraper settings for cAdvisor, and this answer pointed me in the right direction, as after making that change I can now see the correct job
tag on metrics from cAdvisor.
Unfortunately, now some of the charts in the Grafana dashboards are broken. It looks like it no longer picks up the CPU metrics - and instead just displays "No data" for the CPU-related charts.
So, I assume I have to tweak the charts to be able to pick up the metrics correctly again, but I don't see any obvious places to do this in Grafana?
Not sure if it is relevant for the question, but I am running my Kubernetes cluster on Azure Kubernetes Service (AKS).
This is the full values.yaml
I supply to the Helm chart when installing Prometheus:
kubeControllerManager:
enabled: false
kubeScheduler:
enabled: false
kubeEtcd:
enabled: false
kubeProxy:
enabled: false
kubelet:
serviceMonitor:
# Diables the normal cAdvisor scraping, as we add it with the job name "kubernetes-cadvisor" under additionalScrapeConfigs
# The reason for doing this is to enable the VPA to use the metrics for the recommender
# https://github.com/kubernetes/autoscaler/blob/master/vertical-pod-autoscaler/FAQ.md#how-can-i-use-prometheus-as-a-history-provider-for-the-vpa-recommender
cAdvisor: false
prometheus:
prometheusSpec:
retention: 15d
storageSpec:
volumeClaimTemplate:
spec:
# the azurefile storage class is created automatically on AKS
storageClassName: azurefile
accessModes: ["ReadWriteMany"]
resources:
requests:
storage: 50Gi
additionalScrapeConfigs:
- job_name: 'kubernetes-cadvisor'
scheme: https
metrics_path: /metrics/cadvisor
tls_config:
ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
insecure_skip_verify: true
bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token
kubernetes_sd_configs:
- role: node
relabel_configs:
- action: labelmap
regex: __meta_kubernetes_node_label_(.+)
Kubernetes version: 1.21.2
kube-prometheus-stack version: 18.1.1
helm version: version.BuildInfo{Version:"v3.6.3", GitCommit:"d506314abfb5d21419df8c7e7e68012379db2354", GitTreeState:"dirty", GoVersion:"go1.16.5"}
Unfortunately, I don't have access to Azure AKS, so I've reproduced this issue on my GKE cluster. Below I'll provide some explanations that may help to resolve your problem.
First you can try to execute this node_namespace_pod_container:container_cpu_usage_seconds_total:sum_irate
rule to see if it returns any result:
If it doesn't return any records, please read the following paragraphs.
Rather than creating a completely new scrape configuration for cadvisor, I would suggest using one that is generated by default when kubelet.serviceMonitor.cAdvisor: true
, but with a few modifications such as changing the label to job=kubernetes-cadvisor
.
In my example, the 'kubernetes-cadvisor' scrape configuration looks like this:
NOTE: I added this config under the additionalScrapeConfigs
in the values.yaml
file (the rest of the values.yaml
file may be like yours).
- job_name: 'kubernetes-cadvisor'
honor_labels: true
honor_timestamps: true
scrape_interval: 30s
scrape_timeout: 10s
metrics_path: /metrics/cadvisor
scheme: https
authorization:
type: Bearer
credentials_file: /var/run/secrets/kubernetes.io/serviceaccount/token
tls_config:
ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
insecure_skip_verify: true
follow_redirects: true
relabel_configs:
- source_labels: [job]
separator: ;
regex: (.*)
target_label: __tmp_prometheus_job_name
replacement: $1
action: replace
- source_labels: [__meta_kubernetes_service_label_app_kubernetes_io_name]
separator: ;
regex: kubelet
replacement: $1
action: keep
- source_labels: [__meta_kubernetes_service_label_k8s_app]
separator: ;
regex: kubelet
replacement: $1
action: keep
- source_labels: [__meta_kubernetes_endpoint_port_name]
separator: ;
regex: https-metrics
replacement: $1
action: keep
- source_labels: [__meta_kubernetes_endpoint_address_target_kind, __meta_kubernetes_endpoint_address_target_name]
separator: ;
regex: Node;(.*)
target_label: node
replacement: ${1}
action: replace
- source_labels: [__meta_kubernetes_endpoint_address_target_kind, __meta_kubernetes_endpoint_address_target_name]
separator: ;
regex: Pod;(.*)
target_label: pod
replacement: ${1}
action: replace
- source_labels: [__meta_kubernetes_namespace]
separator: ;
regex: (.*)
target_label: namespace
replacement: $1
action: replace
- source_labels: [__meta_kubernetes_service_name]
separator: ;
regex: (.*)
target_label: service
replacement: $1
action: replace
- source_labels: [__meta_kubernetes_pod_name]
separator: ;
regex: (.*)
target_label: pod
replacement: $1
action: replace
- source_labels: [__meta_kubernetes_pod_container_name]
separator: ;
regex: (.*)
target_label: container
replacement: $1
action: replace
- separator: ;
regex: (.*)
target_label: endpoint
replacement: https-metrics
action: replace
- source_labels: [__metrics_path__]
separator: ;
regex: (.*)
target_label: metrics_path
replacement: $1
action: replace
- source_labels: [__address__]
separator: ;
regex: (.*)
modulus: 1
target_label: __tmp_hash
replacement: $1
action: hashmod
- source_labels: [__tmp_hash]
separator: ;
regex: "0"
replacement: $1
action: keep
kubernetes_sd_configs:
- role: endpoints
kubeconfig_file: ""
follow_redirects: true
namespaces:
names:
- kube-system
By default, Prometheus rules fetching data from cAdvisor use job="kubelet"
in their PromQL expressions:
After changing job=kubelet
to job=kubernetes-cadvisor
, we also need to modify this label in the Prometheus rules:
NOTE: We just need to modify the rules that have metrics_path="/metrics/cadvisor
(these are rules that retrieve data from cAdvisor).
$ kubectl get prometheusrules prom-1-kube-prometheus-sta-k8s.rules -o yaml
...
- name: k8s.rules
rules:
- expr: |-
sum by (cluster, namespace, pod, container) (
irate(container_cpu_usage_seconds_total{job="kubernetes-cadvisor", metrics_path="/metrics/cadvisor", image!=""}[5m])
) * on (cluster, namespace, pod) group_left(node) topk by (cluster, namespace, pod) (
1, max by(cluster, namespace, pod, node) (kube_pod_info{node!=""})
)
record: node_namespace_pod_container:container_cpu_usage_seconds_total:sum_irate
...
here we have a few more rules to modify...
After modifying Prometheus rules and waiting some time, we can see if it works as expected. We can try to execute node_namespace_pod_container:container_cpu_usage_seconds_total:sum_irate
as in the beginning.
Additionally, let's check out our Grafana to make sure it has started displaying our dashboards correctly: