prometheus

README

Prometheus Configuration Function

Creates Resource configs to deploy Prometheus on Kubernetes.

Function Features

Function settings are documented in the Options Go type. Metadata and other data is documented in the ConfigFunction type.

Getting Started

In the following example we create Resource configs for a Prometheus server. These configs are meant to be checked into version control, so Secrets are not included. Optionally, all necessary Secrets can be created in-cluster via Jobs -- check out the production demo.

Set up a workspace and define a function configuration.

DEMO=$(mktemp -d)
mkdir $DEMO/functions

cat <<EOF >$DEMO/functions/configmap_my-prometheus.yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: my-prometheus
  namespace: example
  annotations:
    config.kubernetes.io/function: |
      container:
        image: gcr.io/config-functions/prometheus:v0.0.1
EOF

Generate Resources.

config run $DEMO

Generated Resources

The function generates the following resources.

EXPECTED='.
├── [Resource]  ConfigMap example/my-prometheus-server
├── [Resource]  ConfigMap example/my-prometheus
├── [Resource]  Role example/my-prometheus-server
├── [Resource]  RoleBinding example/my-prometheus-server
├── [Resource]  Service example/my-prometheus-server
├── [Resource]  ServiceAccount example/my-prometheus-server
└── [Resource]  StatefulSet example/my-prometheus-server'

TEST="$(config tree $DEMO --graph-structure=owners)"
[ "$TEST" = "$EXPECTED" ]

Configuration

Default Function Configuration

The function adds any missing configuration fields to the function ConfigMap we created above, populating their values with defaults.

EXPECTED='apiVersion: v1
kind: ConfigMap
metadata:
  name: my-prometheus
  namespace: "example"
  labels:
    app.kubernetes.io/instance: my-prometheus
    app.kubernetes.io/name: prometheus-server
  annotations:
    config.kubernetes.io/function: |
      container:
        image: gcr.io/config-functions/prometheus:v0.0.1'

TEST="$(cat $DEMO/functions/configmap_my-prometheus.yaml)"
[ "$TEST" = "$EXPECTED" ]

Adding Scrape Configs

Scrape configs can be added from annotations on the Resources inteded to be scraped for metrics. This function looks for Resources in the same namespace with the annotation config.bzub.dev/prometheus-scrape_configs.

cat <<EOF >$DEMO/example/my-service.yaml
apiVersion: v1
kind: Service
metadata:
  name: my-service
  namespace: example
  annotations:
    config.bzub.dev/prometheus-scrape_configs: |-
      - job_name: my-service
        kubernetes_sd_configs:
          - role: endpoints
            namespaces:
              names:
                - example
        relabel_configs:
          - source_labels: [__meta_kubernetes_service_name]
            action: keep
            regex: my-service
          - source_labels: [__meta_kubernetes_endpoint_port_name]
            action: keep
            regex: metrics
spec:
  ports:
    - name: metrics
      port: 8080
EOF

Delete the old Prometheus server ConfigMap file and regenerate it.

rm $DEMO/example/configmap_my-prometheus-server.yaml
config run $DEMO

EXPECTED='apiVersion: v1
kind: ConfigMap
metadata:
  name: my-prometheus-server
  namespace: "example"
  labels:
    app.kubernetes.io/instance: my-prometheus
    app.kubernetes.io/name: prometheus-server
data:
  prometheus.yml: |-
    global:
      scrape_interval:     15s
      evaluation_interval: 30s
    scrape_configs:
      - job_name: my-service
        kubernetes_sd_configs:
          - role: endpoints
            namespaces:
              names:
                - example
        relabel_configs:
          - source_labels: [__meta_kubernetes_service_name]
            action: keep
            regex: my-service
          - source_labels: [__meta_kubernetes_endpoint_port_name]
            action: keep
            regex: metrics

      - job_name: my-prometheus
        kubernetes_sd_configs:
          - role: endpoints
            namespaces:
              names:
                - example
        relabel_configs:
          - source_labels: [__meta_kubernetes_service_name]
            action: keep
            regex: my-prometheus-server
          - action: labelmap
            regex: __meta_kubernetes_service_label_(.+)
          - source_labels: [__meta_kubernetes_namespace]
            action: replace
            target_label: kubernetes_namespace
          - source_labels: [__meta_kubernetes_service_name]
            action: replace
            target_label: kubernetes_service_name
          - action: labelmap
            regex: __meta_kubernetes_pod_label_(.+)
          - source_labels: [__meta_kubernetes_pod_name]
            action: replace
            target_label: kubernetes_pod_name'

TEST="$(cat $DEMO/example/configmap_my-prometheus-server.yaml)"
[ "$TEST" = "$EXPECTED" ]

Cleanup the demo workspace.

rm -rf $DEMO

Documentation

Index

• Constants
• func Indent(text, indent string) string
• type ConfigFunction
  • func (f *ConfigFunction) Filter(in []*yaml.RNode) ([]*yaml.RNode, error)
• type Options

Constants

const DefaultAppNameAnnotationValue = "prometheus-server"

const ScrapeConfigsAnnotation = "config.bzub.dev/prometheus-scrape_configs"

Functions

func Indent

func Indent(text, indent string) string

indents a block of text with an indent string

Types

type ConfigFunction

type ConfigFunction struct {
	cfunc.ConfigFunction `yaml:",inline"`

	// Data contains various options specific to this config function.
	Data Options
}

ConfigFunction implements kio.Filter and holds information used in Resource templates.

func (*ConfigFunction) Filter

func (f *ConfigFunction) Filter(in []*yaml.RNode) ([]*yaml.RNode, error)

Filter generates Resources.

type Options

type Options struct {
	// ScrapeConfigs are configuration snippets to be included in the
	// Prometheus `scrape_configs`. These are collected from input Resource
	// annotations.
	//
	// https://prometheus.io/docs/prometheus/latest/configuration/configuration/#scrape_config
	ScrapeConfigs []string
}

Options holds settings used in the config function.