Kubernetes Metrics Server

User guide

You can find the user guide in the official Kubernetes documentation.

Design

The detailed design of the project can be found in the following docs:

• Metrics API
• Metrics Server

For the broader view of monitoring in Kubernetes take a look into Monitoring architecture

Deployment

Compatibility matrix:

Metrics Server	Metrics API group/version	Supported Kubernetes version
0.3.x	metrics.k8s.io/v1beta1	1.8+
0.2.x	metrics.k8s.io/v1beta1	1.8+
0.1.x	metrics/v1alpha1	1.7

In order to deploy metrics-server in your cluster run the following command from the top-level directory of this repository:

# Kubernetes 1.7
$ kubectl create -f deploy/1.7/

# Kubernetes > 1.8
$ kubectl create -f deploy/1.8+/

You can also use this helm chart to deploy the metric-server in your cluster (This isn't supported by the metrics-server maintainers): https://github.com/helm/charts/tree/master/stable/metrics-server

Flags

Metrics Server supports all the standard Kubernetes API server flags, as well as the standard Kubernetes glog logging flags. The most commonly-used ones are:

• --logtostderr: log to standard error instead of files in the container. You generally want this on.

• --v=<X>: set log verbosity. It's generally a good idea to run a log level 1 or 2 unless you're encountering errors. At log level 10, large amounts of diagnostic information will be reported, include API request and response bodies, and raw metric results from Kubelet.

• --secure-port=<port>: set the secure port. If you're not running as root, you'll want to set this to something other than the default (port 443).

• --tls-cert-file, --tls-private-key-file: the serving certificate and key files. If not specified, self-signed certificates will be generated, but it's recommended that you use non-self-signed certificates in production.

Additionally, Metrics Server defines a number of flags for configuring its behavior:

• --metric-resolution=<duration>: the interval at which metrics will be scraped from Kubelets (defaults to 60s).

• --kubelet-insecure-tls: skip verifying Kubelet CA certificates. Not recommended for production usage, but can be useful in test clusters with self-signed Kubelet serving certificates.

• --kubelet-port: the port to use to connect to the Kubelet (defaults to the default secure Kubelet port, 10250).

• --kubelet-preferred-address-types: the order in which to consider different Kubelet node address types when connecting to Kubelet. Functions similarly to the flag of the same name on the API server.