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From the documentation:

Cluster add-ons are Services and Replication Controllers (with pods) that are shipped with the Kubernetes binaries and are considered an inherent part of the Kubernetes clusters. [...] On the cluster, the add-ons are kept in /etc/kubernetes/addons on the master node, in yaml files (json is not supported at the moment). [...] users are discouraged to do it on their own - they should rather wait for a new release of Kubernetes that will also contain new versions of add-ons.

My kubernetes setup is running on fedeora and it has been installed via yum. The version is 

Client Version: version.Info{Major:"1", Minor:"1+", GitVersion:"v1.1.0-alpha.0.2175+b6f18c7ce08714", GitCommit:"b6f18c7ce08714c8d4f6019463879a164a41750e", GitTreeState:"clean"}
Server Version: version.Info{Major:"1", Minor:"1+", GitVersion:"v1.1.0-alpha.0.2175+b6f18c7ce08714", GitCommit:"b6f18c7ce08714c8d4f6019463879a164a41750e", GitTreeState:"clean"}

Strangely, the folder /etc/kubernetes/addons/ does not exist.

I would like to activate the sky-dns addon. I have tried to read all available documentation, but it is still not clear to me:

How do I properly install and activate an addon? Preferably so that it will receive automated updates in future?

Konstantin Schubert
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1 Answers1

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First, it isn't clear from the version number what your are actually running. Github shows a v1.1.0-alpha.1 release and a v1.1.0-alpha.0 tag but nothing named v1.1.0-alpha. Also note that neither of those releases were ever marked as "latest" or "released" meaning that they are not suitable for running in production and may contain egregious bugs (they are alpha quality after all). The latest stable release is v1.1.3 if you want to install that instead.

Second, on a bare metal install the cluster add-ons aren't added automatically. If you follow one of the getting started guides, the turn-key solutions will deploy the cluster add-ons automatically. The most important cluster add-on is DNS, and you can follow the manual instructions to get it installed on your cluster.

Robert Bailey
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  • Unfortunately I am required to use an installation of kubernetes in our own data center. Therefore I am unable to use any turn-key solution, which otherwise would have been my first choice. – Konstantin Schubert Dec 09 '15 at 20:19
  • Regarding the manual instructions you linked, maybe I am just blind or I am misunderstanding you. But I have read the document before and I can't find any installation instructions there. – Konstantin Schubert Dec 09 '15 at 20:24
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    It's half way down the section I linked to, starting with "If you are not using a supported cluster setup, you will have to replicate some of this yourself." – Robert Bailey Dec 10 '15 at 04:34
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    Since you are running in your own data center, you should also take a look at http://kubernetes.io/v1.1/docs/getting-started-guides/scratch.html and send feedback about which parts of the document are missing or incorrect. – Robert Bailey Dec 10 '15 at 04:35
  • That means I should just start the components manually? I was hesitant to do that because I thought there was another way which would let me profit from the automated update meachanism described here: https://github.com/kubernetes/kubernetes/blob/release-1.1/cluster/addons/README.md ("A system daemon periodically checks...") – Konstantin Schubert Dec 10 '15 at 11:54
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    The system daemon is something that we install and configure via salt (see https://github.com/kubernetes/kubernetes/tree/master/cluster/saltbase/salt/kube-addons). So if you aren't using salt, that daemon won't exist on your system unless you install it manually (and then drop the cluster add-on manifest files into the right directory). We are working on a more portable version of this feature (called Deployments) which we are hoping will be beta quality in the 1.2 timeframe. – Robert Bailey Dec 10 '15 at 15:30
  • Thank you, I got it running now, after also adding -kube_master_url to the kub2sky options as described here http://stackoverflow.com/a/33628171/1375015 – Konstantin Schubert Dec 10 '15 at 15:40