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This updates the README and walkthrough to use v1.9 API versions, and to use Prometheus v2.
76 lines
3.1 KiB
Markdown
76 lines
3.1 KiB
Markdown
Kubernetes Custom Metrics Adapter for Prometheus
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================================================
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[](https://travis-ci.org/DirectXMan12/k8s-prometheus-adapter)
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This repository contains an implementation of the Kubernetes custom
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metrics API
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([custom.metrics.k8s.io/v1beta1](https://github.com/kubernetes/metrics/tree/master/pkg/apis/custom_metrics)),
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suitable for use with the autoscaling/v2 Horizontal Pod Autoscaler in
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Kubernetes 1.6+.
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Configuration
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-------------
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The adapter takes the standard Kubernetes generic API server arguments
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(including those for authentication and authorization). By default, it
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will attempt to using [Kubernetes in-cluster
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config](https://kubernetes.io/docs/tasks/access-application-cluster/access-cluster/#accessing-the-api-from-a-pod)
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to connect to the cluster.
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It takes the following addition arguments specific to configuring how the
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adapter talks to Prometheus and the main Kubernetes cluster:
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- `--lister-kubeconfig=<path-to-kubeconfig>`: This configures
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how the adapter talks to a Kubernetes API server in order to list
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objects when operating with label selectors. By default, it will use
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in-cluster config.
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- `--metrics-relist-interval=<duration>`: This is the interval at which to
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update the cache of available metrics from Prometheus.
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- `--rate-interval=<duration>`: This is the duration used when requesting
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rate metrics from Prometheus. It *must* be larger than your Prometheus
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collection interval.
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- `--prometheus-url=<url>`: This is the URL used to connect to Prometheus.
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It will eventually contain query parameters to configure the connection.
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Presentation
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------------
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The adapter gathers the names of available metrics from Prometheus
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a regular interval (see [Configuration](#configuration) above), and then
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only exposes metrics that follow specific forms.
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In general:
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- Metrics must have the `namespace` label to be considered.
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- For each label on a metric, if that label name corresponds to
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a Kubernetes resource (like `pod` or `service`), the metric will be
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associated with that resource.
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- Metrics ending in `_total` are assumed to be cumulative, and will be
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exposed without the suffix as a rate metric.
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Detailed information can be found under [docs/format.md](docs/format.md).
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Example
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-------
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A brief walkthrough exists in [docs/walkthrough.md](docs/walkthrough.md).
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Additionally, [@luxas](https://github.com/luxas) has an excellent example
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deployment of Prometheus, this adapter, and a demo pod which serves
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a metric `http_requests_total`, which becomes the custom metrics API
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metric `pods/http_requests`. It also autoscales on that metric using the
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`autoscaling/v2beta1` HorizontalPodAutoscaler.
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It can be found at https://github.com/luxas/kubeadm-workshop. Pay special
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attention to:
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- [Deploying the Prometheus
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Operator](https://github.com/luxas/kubeadm-workshop#deploying-the-prometheus-operator-for-monitoring-services-in-the-cluster)
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- [Setting up the custom metrics adapter and sample
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app](https://github.com/luxas/kubeadm-workshop#deploying-a-custom-metrics-api-server-and-a-sample-app)
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