Prometheus Configuration Guide

Bring your own Prometheus

There are several considerations when disabling the Kubecost included Prometheus deployment. Kubecost strongly recommends installing Kubecost with the bundled Prometheus in most environments.

The Kubecost Prometheus deployment is optimized to not interfere with other observability instrumentation and by default only contains metrics that are useful to the Kubecost product. This results in 70-90% fewer metrics than a Prometheus deployment using default settings.

Additionally, if multi-cluster metric aggregation is required, Kubecost provides a turnkey solution that is highly tuned and simple to support using the included Prometheus deployment.

This feature is accessible to all users. However, please note that comprehensive support is provided with a paid support plan.

Dependency requirements

Kubecost requires the following minimum versions:

• Prometheus: v2.18 (v2.13-2.17 supported with limited functionality)

• cAdvisor: kubelet v1.11.0+

Instructions

Disabling Kubecost's Prometheus deployment

This process is not recommended. Before continuing, review the Bring your own Prometheus section if you haven't already.

1. Pass the following parameters in your Helm install:

```
helm upgrade --install kubecost \
  --repo https://kubecost.github.io/cost-analyzer/ cost-analyzer \
  --namespace kubecost --create-namespace \
  --set global.prometheus.fqdn=http://<prometheus-server-service-name>.<prometheus-server-namespace>.svc:<port> \
  --set global.prometheus.enabled=false
```

The FQDN can be a full path via https://prometheus-prod-us-central-x.grafana.net/api/prom/ if you use Grafana Cloud-managed Prometheus. Learn more in the Grafana Cloud Integration for Kubecost doc.

1. Have your Prometheus scrape the cost-model /metrics endpoint. These metrics are needed for reporting accurate pricing data. Here is an example scrape config:

- job_name: kubecost
  honor_labels: true
  scrape_interval: 1m
  scrape_timeout: 10s
  metrics_path: /metrics
  scheme: http
  dns_sd_configs:
  - names:
    - kubecost-cost-analyzer.<namespace-of-your-kubecost>
    type: 'A'
    port: 9003

This config needs to be added to extraScrapeConfigs in the Prometheus configuration. See the example extraScrapeConfigs.yaml.

1. By default, the Prometheus chart included with Kubecost (bundled-Prometheus) contains scrape configs optimized for Kubecost-required metrics. You need to add those scrape configs jobs into your existing Prometheus setup to allow Kubecost to provide more accurate cost data and optimize the required resources for your existing Prometheus.

You can find the full scrape configs of our bundled-Prometheus here. You can check Prometheus documentation for more information about the scrape config, or read this documentation if you are using Prometheus Operator.

Recording rules

This step is optional. If you do not set up Kubecost's CPU usage recording rule, Kubecost will fall back to a PromQL subquery which may put unnecessary load on your Prometheus.

Kubecost-bundled Prometheus includes a recording rule used to calculate CPU usage max, a critical component of the request right-sizing recommendation functionality. Add the recording rules to reduce query load here.

Alternatively, if your environment supports serviceMonitors and prometheusRules, pass these values to your Helm install:

global:
  prometheus:
    enabled: false
serviceMonitor:
  enabled: true
  # additionalLabels:
  #   label-key: label-value
  networkCosts:
    enabled: true
    # additionalLabels:
    #   label-key: label-value
prometheusRule:
  enabled: true
  # additionalLabels:
  #   label-key: label-value

To confirm this job is successfully scraped by Prometheus, you can view the Targets page in Prometheus and look for a job named kubecost.

Prometheus Targets

Distinguishing clusters

Each cluster must set a unique CLUSTER_ID label as follows:

prometheus:
  server:
    global:
      external_labels:
        cluster_id: my-unique-cluster-id

If you are deploying a multi-cluster Prometheus architecture (i.e. all clusters send metrics to a central Prometheus), you may also need to set the following config. This config specifies the label used in Prometheus to identify the cluster name. The default cluster label is cluster_id, though many environments use the key of cluster. This is important in Kubecost being able to determine which metric belongs to which cluster.

kubecostModel:
  promClusterIDLabel: cluster_id

Troubleshooting

The Diagnostics page (Settings > View Full Diagnostics) provides diagnostic info on your integration. Scroll down to Prometheus Status to verify that your configuration is successful.

Prometheus status diagnostic

Below you can find solutions to common Prometheus configuration problems. View the Kubecost Diagnostics doc for more information.

Misconfigured Prometheus FQDN

Evidenced by the following pod error message No valid prometheus config file at ... and the init pods hanging. We recommend running curl <your_prometheus_url>/api/v1/status/config from a pod in the cluster to confirm that your Prometheus config is returned. Here is an example, but this needs to be updated based on your pod name and Prometheus address:

kubectl exec -i -t --namespace kubecost \
  deployment/kubecost-cost-analyzer -c cost-model -- \
  curl http://<your_prometheus_url>/api/v1/status/config

In the above example, <your_prometheus_url> may include a port number and/or namespace, example: http://prometheus-operator-kube-p-prometheus.monitoring:9090/api/v1/status/config

If the config file is not returned, this is an indication that an incorrect Prometheus address has been provided. If a config file is returned from one pod in the cluster but not the Kubecost pod, then the Kubecost pod likely has its access restricted by a network policy, service mesh, etc.

Context deadline exceeded

Network policies, Mesh networks, or other security related tooling can block network traffic between Prometheus and Kubecost which will result in the Kubecost scrape target state as being down in the Prometheus targets UI. To assist in troubleshooting this type of error you can use the curl command from within the cost-analyzer container to try and reach the Prometheus target. Note the "namespace" and "deployment" name in this command may need updated to match your environment, this example uses the default Kubecost Prometheus deployment.

When successful, this command should return all of the metrics that Kubecost uses. Failures may be indicative of the network traffic being blocked.

kubectl exec -i -t --namespace kubecost \
  deployment/kubecost-cost-analyzer -c cost-model -- \
  curl "http://<your_prometheus_url>/metrics"

Prometheus throttling

Ensure Prometheus isn't being CPU throttled due to a low resource request.

Wrong dependency version

Review the Dependency Requirements section above

Missing scrape configs

Visit Prometheus Targets page (screenshot above)

Data incorrectly is a single namespace

Make sure that honor_labels is enabled

Negative idle reported

Single cluster tests

Ensure results are not null for both queries below.

1. Make sure Prometheus is scraping Kubecost search metrics for: node_total_hourly_cost

kubectl exec -i -t --namespace kubecost \
  deployment/kubecost-cost-analyzer -c cost-model -- \
  curl "http://localhost:9003/prometheusQuery?query=node_total_hourly_cost"

1. Ensure kube-state-metrics are available: kube_node_status_capacity

kubectl exec -i -t --namespace kubecost \
  deployment/kubecost-cost-analyzer -c cost-model -- \
  curl "http://localhost:9003/prometheusQuery?query=kube_node_status_capacity"

For both queries, verify nodes are returned. A successful response should look like:

{"status":"success","data":{"resultType":"vector","result":[{"metric":{"__name__":"node_total_hourly_cost","instance":"aks-agentpool-81479558-vmss000001","instance_type":"Standard_B4ms","job":"kubecost","node":"aks-agentpool-81479558-vmss000001","provider_id":"azure:///.../virtualMachines/1","region":"eastus"},"value":[1673020150,"0.16599565032196045"]}]}}

An error will look like:

{"status":"success","data":{"resultType":"vector","result":[]}}

Enterprise multi-cluster test

Ensure that all clusters and nodes have values- output should be similar to the above Single Cluster Tests

1. Make sure Prometheus is scraping Kubecost search metrics for: node_total_hourly_cost

kubectl exec -i -t --namespace kubecost \
  deployment/kubecost-cost-analyzer -c cost-model -- \
  curl -G http://localhost:9003/thanosQuery \
  -d time=`date -d '1 day ago' "+%Y-%m-%dT%H:%M:%SZ"` \
  --data-urlencode "query=avg (sum_over_time(node_total_hourly_cost[1d])) by (cluster_id, node)" \
  | jq

On macOS, change date -d '1 day ago' to date -v '-1d'

1. Ensure kube-state-metrics are available: kube_node_status_capacity

kubectl exec -i -t --namespace kubecost \
  deployment/kubecost-cost-analyzer -c cost-model -- \
  curl -G http://localhost:9003/thanosQuery \
  -d time=`date -d '1 day ago' "+%Y-%m-%dT%H:%M:%SZ"` \
  --data-urlencode "query=avg (sum_over_time(kube_node_status_capacity[1d])) by (cluster_id, node)" \
  | jq

For both queries, verify nodes are returned. A successful response should look like:

{"status":"success","data":{"resultType":"vector","result":[{"metric":{"__name__":"node_total_hourly_cost","instance":"aks-agentpool-81479558-vmss000001","instance_type":"Standard_B4ms","job":"kubecost","node":"aks-agentpool-81479558-vmss000001","provider_id":"azure:///.../virtualMachines/1","region":"eastus"},"value":[1673020150,"0.16599565032196045"]}]}}

An error will look like:

{"status":"success","data":{"resultType":"vector","result":[]}}