Prometheus Adapter

Installs the Prometheus Adapter for the Custom Metrics API. Custom metrics are used in Kubernetes by Horizontal Pod Autoscalers to scale workloads based upon your own metric pulled from an external metrics provider like Prometheus. This chart complements the metrics-server chart that provides resource only metrics.

Prerequisites

Kubernetes 1.11+

Installing the Chart

To install the chart with the release name my-release:

$ helm install --name my-release stable/prometheus-adapter

This command deploys the prometheus adapter with the default configuration. The configuration section lists the parameters that can be configured during installation.

Using the Chart

To use the chart, ensure the prometheus.url and prometheus.port are configured with the correct Prometheus service endpoint. If Prometheus is exposed under HTTPS the host's CA Bundle must be exposed to the container using extraVolumes and extraVolumeMounts.

Additionally, the chart comes with a set of default rules out of the box but they may pull in too many metrics or not map them correctly for your needs. Therefore, it is recommended to populate rules.custom with a list of rules (see the config document for the proper format).

Finally, to configure your Horizontal Pod Autoscaler to use the custom metric, see the custom metrics section of the HPA walkthrough.

The Prometheus Adapter can serve three different metrics APIs:

Custom Metrics

Enabling this option will cause custom metrics to be served at /apis/custom.metrics.k8s.io/v1beta1. Enabled by default when rules.default is true, but can be customized by populating rules.custom:

rules:
  custom:
  - seriesQuery: '{__name__=~"^some_metric_count$"}'
    resources:
      template: <<.Resource>>
    name:
      matches: ""
      as: "my_custom_metric"
    metricsQuery: sum(<<.Series>>{<<.LabelMatchers>>}) by (<<.GroupBy>>)

External Metrics

Enabling this option will cause external metrics to be served at /apis/external.metrics.k8s.io/v1beta1. Can be enabled by populating rules.external:

rules:
  external:
  - seriesQuery: '{__name__=~"^some_metric_count$"}'
    resources:
      template: <<.Resource>>
    name:
      matches: ""
      as: "my_external_metric"
    metricsQuery: sum(<<.Series>>{<<.LabelMatchers>>}) by (<<.GroupBy>>)

Resource Metrics

Enabling this option will cause resource metrics to be served at /apis/metrics.k8s.io/v1beta1. Resource metrics will allow pod CPU and Memory metrics to be used in Horizontal Pod Autoscalers as well as the kubectl top command. Can be enabled by populating rules.resource:

rules:
  resource:
    cpu:
      containerQuery: sum(rate(container_cpu_usage_seconds_total{<<.LabelMatchers>>}[3m])) by (<<.GroupBy>>)
      nodeQuery: sum(rate(container_cpu_usage_seconds_total{<<.LabelMatchers>>, id='/'}[3m])) by (<<.GroupBy>>)
      resources:
        overrides:
          instance:
            resource: node
          namespace:
            resource: namespace
          pod_name:
            resource: pod
      containerLabel: container_name
    memory:
      containerQuery: sum(container_memory_working_set_bytes{<<.LabelMatchers>>}) by (<<.GroupBy>>)
      nodeQuery: sum(container_memory_working_set_bytes{<<.LabelMatchers>>,id='/'}) by (<<.GroupBy>>)
      resources:
        overrides:
          instance:
            resource: node
          namespace:
            resource: namespace
          pod_name:
            resource: pod
      containerLabel: container_name
    window: 3m

NOTE: Setting a value for rules.resource will also deploy the resource metrics API service, providing the same functionality as metrics-server. As such it is not possible to deploy them both in the same cluster.

Uninstalling the Chart

To uninstall/delete the my-release deployment:

$ helm delete my-release

The command removes all the Kubernetes components associated with the chart and deletes the release.

Configuration

The following table lists the configurable parameters of the Prometheus Adapter chart and their default values.

Parameter	Description	Default
affinity	Node affinity	{}
image.repository	Image repository	directxman12/k8s-prometheus-adapter-amd64
image.tag	Image tag	v0.5.0
image.pullPolicy	Image pull policy	IfNotPresent
image.pullSecrets	Image pull secrets	{}
logLevel	Log level	4
metricsRelistInterval	Interval at which to re-list the set of all available metrics from Prometheus	1m
nodeSelector	Node labels for pod assignment	{}
podAnnotations	Annotations to add to the pod	{}
priorityClassName	Pod priority	``
prometheus.url	Url of where we can find the Prometheus service	http://prometheus.default.svc
prometheus.port	Port of where we can find the Prometheus service, zero to omit this option	9090
rbac.create	If true, create & use RBAC resources	true
resources	CPU/Memory resource requests/limits	{}
rules.default	If true, enable a set of default rules in the configmap	true
rules.custom	A list of custom configmap rules	[]
rules.existing	The name of an existing configMap with rules. Overrides default, custom and external.	``
rules.external	A list of custom rules for external metrics API	[]
rules.resource	resourceRules to set in configmap rules	{}
service.annotations	Annotations to add to the service	{}
service.port	Service port to expose	443
service.type	Type of service to create	ClusterIP
serviceAccount.create	If true, create & use Serviceaccount	true
serviceAccount.name	If not set and create is true, a name is generated using the fullname template	``
tls.enable	If true, use the provided certificates. If false, generate self-signed certs	false
tls.ca	Public CA file that signed the APIService (ignored if tls.enable=false)	``
tls.key	Private key of the APIService (ignored if tls.enable=false)	``
tls.certificate	Public key of the APIService (ignored if tls.enable=false)	``
extraVolumeMounts	Any extra volumes mounts	[]
extraVolumes	Any extra volumes	[]
tolerations	List of node taints to tolerate	[]

Specify each parameter using the --set key=value[,key=value] argument to helm install. For example,

$ helm install --name my-release \
  --set logLevel=1 \
 stable/prometheus-adapter

Alternatively, a YAML file that specifies the values for the above parameters can be provided while installing the chart. For example,

$ helm install --name my-release -f values.yaml stable/prometheus-adapter