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kube-prometheus

README.md

kube-prometheus

Note that everything in the contrib/kube-prometheus/ directory is experimental and may change significantly at any time.

This repository collects Kubernetes manifests, Grafana dashboards, and Prometheus rules combined with documentation and scripts to provide easy to operate end-to-end Kubernetes cluster monitoring with Prometheus using the Prometheus Operator.

The content of this project is written in jsonnet. This project could both be described as a package as well as a library.

Components included in this package:

This stack is meant for cluster monitoring, so it is pre-configured to collect metrics from all Kubernetes components. In addition to that it delivers a default set of dashboards and alerting rules. Many of the useful dashboards and alerts come from the kubernetes-mixin project, similar to this project it provides composable jsonnet as a library for users to customize to their needs.

Table of contents

Prerequisites

You will need a Kubernetes cluster, that's it! By default it is assumed, that the kubelet uses token authN and authZ, as otherwise Prometheus needs a client certificate, which gives it full access to the kubelet, rather than just the metrics. Token authN and authZ allows more fine grained and easier access control.

This means the kubelet configuration must contain these flags:

  • --authentication-token-webhook=true This flag enables, that a ServiceAccount token can be used to authenticate against the kubelet(s).
  • --authorization-mode=Webhook This flag enables, that the kubelet will perform an RBAC request with the API to determine, whether the requesting entity (Prometheus in this case) is allow to access a resource, in specific for this project the /metrics endpoint.

minikube

In order to just try out this stack, start minikube with the following command:

$ minikube delete && minikube start --kubernetes-version=v1.10.1 --memory=4096 --bootstrapper=kubeadm --extra-config=kubelet.authentication-token-webhook=true --extra-config=kubelet.authorization-mode=Webhook --extra-config=scheduler.address=0.0.0.0 --extra-config=controller-manager.address=0.0.0.0

Quickstart

This project is intended to be used as a library (i.e. the intent is not for you to create your own modified copy of this repository).

Though for a quickstart a compiled version of the Kubernetes manifests generated with this library (specifically with example.jsonnet) is checked into this repository in order to try the content out quickly. To try out the stack un-customized run:

  • Simply create the stack:
$ kubectl create -f manifests/ || true
$ kubectl create -f manifests/ 2>/dev/null || true  # This command sometimes may need to be done twice
  • And to teardown the stack:
$ kubectl delete -f manifests/ || true

Customizing Kube-Prometheus

This section:

  • describes how to customize the kube-prometheus library via compiling the kube-prometheus manifests yourself (as an alternative to the Quickstart section).
  • still doesn't require you to make a copy of this entire repository, but rather only a copy of a few select files.

Installing

The content of this project consists of a set of jsonnet files making up a library to be consumed.

Install this library in your own project with jsonnet-bundler (the jsonnet package manager):

$ mkdir my-kube-prometheus; cd my-kube-prometheus
$ jb init  # Creates the initial/empty `jsonnetfile.json`
# Install the kube-prometheus dependency
$ jb install github.com/coreos/prometheus-operator/contrib/kube-prometheus/jsonnet/kube-prometheus  # Creates `vendor/` & `jsonnetfile.lock.json`, and fills in `jsonnetfile.json`

jb can be installed with go get github.com/jsonnet-bundler/jsonnet-bundler/cmd/jb

An e.g. of how to install a given version of this library: jb install github.com/coreos/prometheus-operator/contrib/kube-prometheus/jsonnet/kube-prometheus/@v0.22.0

In order to update the kube-prometheus dependency, simply use the jsonnet-bundler update functionality: $ jb update

Compiling

e.g. of how to compile the manifests: ./build.sh example.jsonnet

Here's example.jsonnet:

local kp = (import 'kube-prometheus/kube-prometheus.libsonnet') + {
  _config+:: {
    namespace: 'monitoring',
  },
};

{ ['00namespace-' + name]: kp.kubePrometheus[name] for name in std.objectFields(kp.kubePrometheus) } +
{ ['0prometheus-operator-' + name]: kp.prometheusOperator[name] for name in std.objectFields(kp.prometheusOperator) } +
{ ['node-exporter-' + name]: kp.nodeExporter[name] for name in std.objectFields(kp.nodeExporter) } +
{ ['kube-state-metrics-' + name]: kp.kubeStateMetrics[name] for name in std.objectFields(kp.kubeStateMetrics) } +
{ ['alertmanager-' + name]: kp.alertmanager[name] for name in std.objectFields(kp.alertmanager) } +
{ ['prometheus-' + name]: kp.prometheus[name] for name in std.objectFields(kp.prometheus) } +
{ ['grafana-' + name]: kp.grafana[name] for name in std.objectFields(kp.grafana) }

And here's the build.sh script (which uses vendor/ to render all manifests in a json structure of {filename: manifest-content}):

#!/usr/bin/env bash

# This script uses arg $1 (name of *.jsonnet file to use) to generate the manifests/*.yaml files.

set -e
set -x
# only exit with zero if all commands of the pipeline exit successfully
set -o pipefail

# Make sure to start with a clean 'manifests' dir
rm -rf manifests
mkdir manifests

                                               # optional, but we would like to generate yaml, not json
jsonnet -J vendor -m manifests "${1-example.jsonnet}" | xargs -I{} sh -c 'cat {} | gojsontoyaml > {}.yaml; rm -f {}' -- {}

Note you need jsonnet (go get github.com/google/go-jsonnet/jsonnet) and gojsontoyaml (go get github.com/brancz/gojsontoyaml) installed to run build.sh. If you just want json output, not yaml, then you can skip the pipe and everything afterwards.

This script runs the jsonnet code, then reads each key of the generated json and uses that as the file name, and writes the value of that key to that file, and converts each json manifest to yaml.

Containerized Installing and Compiling

If you don't care to have jb nor jsonnet nor gojsontoyaml installed, then build the po-jsonnet Docker image (this is something you'll need a copy of this repository for). Do the following from this kube-prometheus directory:

$ make ../../hack/jsonnet-docker-image

Then you can do commands such as the following:

docker run \
	--rm \
	-v `pwd`:`pwd` \
	--workdir `pwd` \
	po-jsonnet jb init

docker run \
	--rm \
	-v `pwd`:`pwd` \
	--workdir `pwd` \
	po-jsonnet jb install github.com/coreos/prometheus-operator/contrib/kube-prometheus/jsonnet/kube-prometheus

docker run \
	--rm \
	-v `pwd`:`pwd` \
	--workdir `pwd` \
	po-jsonnet ./build.sh example.jsonnet

Configuration

Jsonnet has the concept of hidden fields. These are fields, that are not going to be rendered in a result. This is used to configure the kube-prometheus components in jsonnet. In the example jsonnet code of the above Usage section, you can see an example of this, where the namespace is being configured to be monitoring. In order to not override the whole object, use the +:: construct of jsonnet, to merge objects, this way you can override individual settings, but retain all other settings and defaults.

These are the available fields with their respective default values:

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

    versions+:: {
        alertmanager: "v0.15.0",
        nodeExporter: "v0.15.2",
        kubeStateMetrics: "v1.3.1",
        kubeRbacProxy: "v0.3.1",
        addonResizer: "1.0",
        prometheusOperator: "v0.18.1",
        prometheus: "v2.2.1",
    },

    imageRepos+:: {
        prometheus: "quay.io/prometheus/prometheus",
        alertmanager: "quay.io/prometheus/alertmanager",
        kubeStateMetrics: "quay.io/coreos/kube-state-metrics",
        kubeRbacProxy: "quay.io/coreos/kube-rbac-proxy",
        addonResizer: "quay.io/coreos/addon-resizer",
        nodeExporter: "quay.io/prometheus/node-exporter",
        prometheusOperator: "quay.io/coreos/prometheus-operator",
    },

    prometheus+:: {
        names: 'k8s',
        replicas: 2,
        rules: {},
    },

    alertmanager+:: {
      name: 'main',
      config: |||
        global:
          resolve_timeout: 5m
        route:
          group_by: ['job']
          group_wait: 30s
          group_interval: 5m
          repeat_interval: 12h
          receiver: 'null'
          routes:
          - match:
              alertname: DeadMansSwitch
            receiver: 'null'
        receivers:
        - name: 'null'
      |||,
      replicas: 3,
    },

    kubeStateMetrics+:: {
      collectors: '',  // empty string gets a default set
      scrapeInterval: '30s',
      scrapeTimeout: '30s',

      baseCPU: '100m',
      baseMemory: '150Mi',
      cpuPerNode: '2m',
      memoryPerNode: '30Mi',
    },
	},
}

The grafana definition is located in a different project (https://github.com/brancz/kubernetes-grafana), but needed configuration can be customized from the same top level _config field. For example to allow anonymous access to grafana, add the following _config section:

      grafana+:: {
        config: { // http://docs.grafana.org/installation/configuration/
          sections: {
            "auth.anonymous": {enabled: true},
          },
        },
      },

Customization Examples

Jsonnet is a turing complete language, any logic can be reflected in it. It also has powerful merge functionalities, allowing sophisticated customizations of any kind simply by merging it into the object the library provides.

Cluster Creation Tools

A common example is that not all Kubernetes clusters are created exactly the same way, meaning the configuration to monitor them may be slightly different. For kubeadm and bootkube and kops clusters there are mixins available to easily configure these:

kubeadm:

(import 'kube-prometheus/kube-prometheus.libsonnet') +
(import 'kube-prometheus/kube-prometheus-kubeadm.libsonnet')

bootkube:

(import 'kube-prometheus/kube-prometheus.libsonnet') +
(import 'kube-prometheus/kube-prometheus-bootkube.libsonnet')

kops:

(import 'kube-prometheus/kube-prometheus.libsonnet') +
(import 'kube-prometheus/kube-prometheus-kops.libsonnet')

NodePorts

Another mixin that may be useful for exploring the stack is to expose the UIs of Prometheus, Alertmanager and Grafana on NodePorts:

(import 'kube-prometheus/kube-prometheus.libsonnet') +
(import 'kube-prometheus/kube-prometheus-node-ports.libsonnet')

Prometheus Object Name

To give another customization example, the name of the Prometheus object provided by this library can be overridden:

((import 'kube-prometheus/kube-prometheus.libsonnet') + {
   prometheus+: {
     prometheus+: {
       metadata+: {
         name: 'my-name',
       },
     },
   },
 }).prometheus.prometheus

node-exporter DaemonSet namespace

Standard Kubernetes manifests are all written using ksonnet-lib, so they can be modified with the mixins supplied by ksonnet-lib. For example to override the namespace of the node-exporter DaemonSet:

local k = import 'ksonnet/ksonnet.beta.3/k.libsonnet';
local daemonset = k.apps.v1beta2.daemonSet;

((import 'kube-prometheus/kube-prometheus.libsonnet') + {
   nodeExporter+: {
     daemonset+:
       daemonset.mixin.metadata.withNamespace('my-custom-namespace'),
   },
 }).nodeExporter.daemonset

Alertmanager configuration

The Alertmanager configuration is located in the _config.alertmanager.config configuration field. In order to set a custom Alertmanager configuration simply set this field.

((import 'kube-prometheus/kube-prometheus.libsonnet') + {
   _config+:: {
     alertmanager+: {
       config: |||
         global:
           resolve_timeout: 10m
         route:
           group_by: ['job']
           group_wait: 30s
           group_interval: 5m
           repeat_interval: 12h
           receiver: 'null'
           routes:
           - match:
               alertname: DeadMansSwitch
             receiver: 'null'
         receivers:
         - name: 'null'
       |||,
     },
   },
 }).alertmanager.secret

In the above example the configuration has been inlined, but can just as well be an external file imported in jsonnet via the importstr function.

((import 'kube-prometheus/kube-prometheus.libsonnet') + {
   _config+:: {
     alertmanager+: {
       config: importstr 'alertmanager-config.yaml',
     },
   },
 }).alertmanager.secret

Adding additional namespaces to monitor

In order to monitor additional namespaces, the Prometheus server requires the appropriate Role and RoleBinding to be able to discover targets from that namespace. By default the Prometheus server is limited to the three namespaces it requires: default, kube-system and the namespace you configure the stack to run in via $._config.namespace. This is specified in $._config.prometheus.namespaces, to add new namespaces to monitor, simply append the additional namespaces:

local kp = (import 'kube-prometheus/kube-prometheus.libsonnet') + {
  _config+:: {
    namespace: 'monitoring',

    prometheus+:: {
      namespaces+: ['my-namespace', 'my-second-namespace'],
    },
  },
};

{ ['00namespace-' + name]: kp.kubePrometheus[name] for name in std.objectFields(kp.kubePrometheus) } +
{ ['0prometheus-operator-' + name]: kp.prometheusOperator[name] for name in std.objectFields(kp.prometheusOperator) } +
{ ['node-exporter-' + name]: kp.nodeExporter[name] for name in std.objectFields(kp.nodeExporter) } +
{ ['kube-state-metrics-' + name]: kp.kubeStateMetrics[name] for name in std.objectFields(kp.kubeStateMetrics) } +
{ ['alertmanager-' + name]: kp.alertmanager[name] for name in std.objectFields(kp.alertmanager) } +
{ ['prometheus-' + name]: kp.prometheus[name] for name in std.objectFields(kp.prometheus) } +
{ ['grafana-' + name]: kp.grafana[name] for name in std.objectFields(kp.grafana) }

Static etcd configuration

In order to configure a static etcd cluster to scrape there is a simple kube-prometheus-static-etcd.libsonnet mixin prepared - see etcd.jsonnet for an example of how to use that mixin, and Monitoring external etcd for more information.

Note that monitoring etcd in minikube is currently not possible because of how etcd is setup. (minikube's etcd binds to 127.0.0.1:2379 only, and within host networking namespace.)

Customizing Prometheus alerting/recording rules and Grafana dashboards

See developing Prometheus rules and Grafana dashboards guide.

Exposing Prometheus/Alermanager/Grafana via Ingress

See exposing Prometheus/Alertmanager/Grafana guide.

Minikube Example

To use an easy to reproduce example, see minikube.jsonnet, which uses the minikube setup as demonstrated in Prerequisites. Because we would like easy access to our Prometheus, Alertmanager and Grafana UIs, minikube.jsonnet exposes the services as NodePort type services.

Troubleshooting

Error retrieving kubelet metrics

Should the Prometheus /targets page show kubelet targets, but not able to successfully scrape the metrics, then most likely it is a problem with the authentication and authorization setup of the kubelets.

As described in the Prerequisites section, in order to retrieve metrics from the kubelet token authentication and authorization must be enabled. Some Kubernetes setup tools do not enable this by default.

If you are using Google's GKE product, see [docs/GKE-cadvisor-support.md].

Authentication problem

The Prometheus /targets page will show the kubelet job with the error 403 Unauthorized, when token authentication is not enabled. Ensure, that the --authentication-token-webhook=true flag is enabled on all kubelet configurations.

Authorization problem

The Prometheus /targets page will show the kubelet job with the error 401 Unauthorized, when token authorization is not enabled. Ensure that the --authorization-mode=Webhook flag is enabled on all kubelet configurations.

kube-state-metrics resource usage

In some environments, kube-state-metrics may need additional resources. One driver for more resource needs, is a high number of namespaces. There may be others.

kube-state-metrics resource allocation is managed by addon-resizer You can control it's parameters by setting variables in the config. They default to:

    kubeStateMetrics+:: {
      baseCPU: '100m',
      cpuPerNode: '2m',
      baseMemory: '150Mi',
      memoryPerNode: '30Mi',
    }

Contributing

All .yaml files in the /manifests folder are generated via Jsonnet. Contributing changes will most likely include the following process:

  1. Make your changes in the respective *.jsonnet file.
  2. Commit your changes (This is currently necessary due to our vendoring process. This is likely to change in the future).
  3. Generate dependent *.yaml files: make generate-in-docker.
  4. Commit the generated changes.