"kubeadm init" on offline environment

[khj809]

Hi. I'm trying to set up kubernetes cluster on my private network.
All machines are RHEL 7.3 and use latest kubernetes version (v1.8.1) with docker-ce 17.03.2.
I thought that everything I need is some packages(kubeadm, kubectl, kubelet, kubernetes-cni and dependencies) and images (starts with gcr.io/google_containers/... and pod network images), so I prepared and installed them. But when I run "kubeadm init", it still requires internet connection with following messages.

Unable to get URL "https://dl.k8s.io/release/stable-1.8.txt": Get https://dl.k8s.io/release/stable-1.8.txt: dial tcp: lookup dl.k8s.io on [::1]:53: read udp [::1]:54829->[::1]:53: read: connection refused

What should I do anything else?

[k8s-github-robot]

@khj809
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[wackxu]

@khj809 you can add a flag --kubernetes-version=v1.8.1 then it will skip request the URL

[khj809]

@wackxu Thanks! It works!

[yaniveliash]

Doesn't work on v1.10 offline mode with the statement -> --kubernetes-version=stable-1.10

[nsulek]

you can try with

kubeadm init --kubernetes-version=v1.10.0

it works for me

[brentpearson]

Is there a guide anywhere on the internet for getting this to work? I know I've got to somehow do the following:

• Setup a local Docker registry.
• Get the Docker images that "kubeadm init" needs into the local Docker registry.
• Make the "kubeadm init" command use the local Docker registry to get the Docker images.

I thought I had accomplished this. I can run "docker images" and it lists all the images that I believe "kubeadm init" needs, but something still isn't working. I discovered running a "docker pull " for one of the images that "docker images" shows doesn't work (can't connect, or says image not available if I precede it with my local registry machine's address instead of the remote domain), so that's probably part of the problem.

Even if that was working, is that it? I'm betting there's more, and it'd be good to have a clear procedure for how to get the "kubeadm init" command to work on a machine with no internet access. I've found plenty of search results with the topic being raise, but none with any working solutions.

[antonputra]

You can create config.yaml file, for example

apiVersion: kubeadm.k8s.io/v1alpha1
kind: MasterConfiguration
api:
  advertiseAddress: 10.44.70.201
networking:
  podSubnet: 192.168.0.0/16
kubernetesVersion: 1.10.5

and run kubeadm init --config=kubeadm-config.yaml

[weisjohn]

NOTE: The --config file option also works for a few other kubeadm commands, such as kubeadm alpha phase certs apiserver and kubeadm alpha phase certs etcd-peer, which is helpful when you're running in offline mode (see kubernetes/kubeadm#338 (comment)).

For those commands, I was able to use a config.yml that looked simply like:

kubernetesVersion: 1.11.2

So, my command was:

$ kubeadm alpha phase certs apiserver --config=./config.yml