Prometheus Monitoring Mixins

A mixin is a set of Grafana dashboards and Prometheus rules and alerts, packaged together in a reuseable and extensible bundle. Mixins are written in jsonnet, and are typically installed and updated with jsonnet-bundler.

For more information about mixins, see:

How to use mixins.

Mixins are designed to be vendored into the repo with your infrastructure config. To do this, use jsonnet-bundler:

You then have three options for deploying your dashboards

  1. Generate the config files and deploy them yourself.
  2. Use ksonnet to deploy this mixin along with Prometheus and Grafana.
  3. Use kube-prometheus to deploy this mixin.

Generate config files

You can manually generate the alerts, dashboards and rules files, but first you must install some tools:

$ go get github.com/jsonnet-bundler/jsonnet-bundler/cmd/jb

# macOS
$ brew install jsonnet

# Archlinux AUR
$ yay -S jsonnet

Then, grab the mixin and its dependencies:

$ git clone https://github.com/<mixin org>/<mixin repo>
$ cd <mixin repo>
$ jb install

Finally, build the mixin:

$ make prometheus_alerts.yaml
$ make prometheus_rules.yaml
$ make dashboards_out

The prometheus_alerts.yaml and prometheus_rules.yaml file then need to passed to your Prometheus server, and the files in dashboards_out need to be imported into you Grafana server. The exact details will depending on how you deploy your monitoring stack to Kubernetes.

Using with prometheus-ksonnet

Alternatively you can also use the mixin with prometheus-ksonnet, a ksonnet module to deploy a fully-fledged Prometheus-based monitoring system for Kubernetes:

Make sure you have at least ksonnet v0.8.0:

$ brew install ksonnet/tap/ks
$ ks version
ksonnet version: 0.13.1
jsonnet version: v0.11.2
client-go version: kubernetes-1.10.4

In your config repo, if you don’t have a ksonnet application, make a new one (will copy credentials from current context):

$ ks init <application name>
$ cd <application name>
$ ks env add default

Grab the kubernetes-jsonnet module using and its dependencies, which include the kubernetes-mixin:

$ go get github.com/jsonnet-bundler/jsonnet-bundler/cmd/jb
$ jb init
$ jb install github.com/kausalco/public/prometheus-ksonnet

Assuming you want to run in the default namespace (‘environment’ in ksonnet parlance), add the follow to the file environments/default/main.jsonnet:


local prometheus = import "prometheus-ksonnet/prometheus-ksonnet.libsonnet";

prometheus {
  _config+:: {
    namespace: "default",
  },
}

Apply your config:

$ ks apply default

Using kube-prometheus

See the kube-prometheus docs for instructions on how to use mixins with kube-prometheus.

Customising the mixin

Mixins typically allows you to override the selectors used for various jobs, to match those used in your Prometheus set.

This example uses the kubernetes-mixin. In a new directory, add a file mixin.libsonnet:


local kubernetes = import "kubernetes-mixin/mixin.libsonnet";

kubernetes {
  _config+:: {
    kubeStateMetricsSelector: 'job="kube-state-metrics"',
    cadvisorSelector: 'job="kubernetes-cadvisor"',
    nodeExporterSelector: 'job="kubernetes-node-exporter"',
    kubeletSelector: 'job="kubernetes-kubelet"',
  },
}

Then, install the kubernetes-mixin:

$ jb init
$ jb install github.com/kubernetes-monitoring/kubernetes-mixin

Generate the alerts, rules and dashboards:

$ jsonnet -J vendor -S -e 'std.manifestYamlDoc((import "mixin.libsonnet").prometheusAlerts)' > alerts.yml
$ jsonnet -J vendor -S -e 'std.manifestYamlDoc((import "mixin.libsonnet").prometheusRules)' >files/rules.yml
$ jsonnet -J vendor -m files/dashboards -e '(import "mixin.libsonnet").grafanaDashboards'

Guidelines for alert names, labels, and annotations

Prometheus alerts deliberately allow users to define their own schema for names, labels, and annotations. The following is a style guide recommended for alerts in monitoring mixins. Following this guide helps creating useful notification templates for all mixins and customizing mixin alerts in a unified fashion.

The alert name is a terse description of the alerting condition, using camel case, without whitespace, starting with a capital letter. The first component of the name should be shared between all alerts of a mixin (or between a group of related alerts within a larger mixin). Examples: NodeFilesystemAlmostOutOfFiles (from the node-exporter mixin, PrometheusNotificationQueueRunningFull (from the Prometheus mixin).

To mark the severity of an alert, use a label called severity with one of the following label values:

  • critical for alerts that require immediate action. For a production system, those alerts will usually hit a pager.
  • warning for alerts that require action eventually but not urgently enough to wake someone up or require them to immediately interrupt what they are working on. A typical routing target for those alerts is some kind of ticket queueing or bug tracking system.
  • info for alerts that do not require any action by itself but mark something as “out of the ordinary”. Those alerts aren’t usually routed anywhere, but can be inspected during troubleshooting.

An alert can have the following annotations:

  • summary (mandatory): Essentially a more comprehensive and readable version of the alert name. Use a human-readable sentence, starting with a capital letter and ending with a period. Use a static string or, if dynamic expansion is needed, aim for expanding into the same string for alerts that are typically grouped together into one notification. In that way, it can be used as a common “headline” for all alerts in the notification template. Examples: Filesystem has less than 3% inodes left. (for the NodeFilesystemAlmostOutOfFiles alert mentioned above), Prometheus alert notification queue predicted to run full in less than 30m. (for the PrometheusNotificationQueueRunningFull alert mentioned above).
  • description (mandatory): A detailed description of a single alert, with most of the important information templated in. The description usually expands into a different string for every individual alert within a notification. A notification template can iterate through all the descriptions and format them into a list. Examples (again corresponding to the examples above): Filesystem on {{ $labels.device }} at {{ $labels.instance }} has only {{ printf "%.2f" $value }}% available inodes left., Alert notification queue of Prometheus %(prometheusName)s is running full..

Note that we plan to add recommended optional annotations for a runbook link (presumably called runbook_url) and a dashboard link (dashboard_url). However, we still need to work out how to configure patterns for those URLs across mixins in a useful way.