Updating image and docs for metrics-server add-on

[Cryptophobia]

Updating image to v0.3.1 and adding more information to README on custom args. All this is the latest info from https://github.com/kubernetes-incubator/metrics-server/

EDIT: Changed image from k8s.gcr.io/metrics-server-amd64:v0.3.1 to gcr.io/google_containers/metrics-server-amd64:v0.3.1 as that is the official location of the production helm chart images.

[chrisz100]

/ok-to-test

[Cryptophobia]

Changed image from k8s.gcr.io/metrics-server-amd64:v0.3.1 to gcr.io/google_containers/metrics-server-amd64:v0.3.1 as that is the official location of the production helm chart images.

[justinsb]

Thanks @Cryptophobia

Question though - I think the images are supposed to be k8s.gcr.io - where are you seeing that the official image is something different?

[justinsb]

/approve
/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Cryptophobia, justinsb

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [justinsb]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[Cryptophobia]

Thanks @Cryptophobia

Question though - I think the images are supposed to be k8s.gcr.io - where are you seeing that the official image is something different?

Hey @justinsb,
Originally, the images from the kubernetes-incubator organization deployment were used and they are found at k8s.gcr.io. You can find the images defined here.

However, after looking at the official helm repo (non-k8s-incubator) for the metrics-server, I noticed that the images were the same versions and they can be found on gcr.io/google_containers/metrics-server-amd64. You can find the images defined in the deployment here.