John Mulhausen
156 lines
4.4 KiB
Markdown
156 lines
4.4 KiB
Markdown
---
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layout: docwithnav
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title: "Sharing Cluster Access"
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---
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<!-- BEGIN MUNGE: UNVERSIONED_WARNING -->
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<!-- END MUNGE: UNVERSIONED_WARNING -->
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# Sharing Cluster Access
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Client access to a running Kubernetes cluster can be shared by copying
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the `kubectl` client config bundle ([kubeconfig](kubeconfig-file.html)).
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This config bundle lives in `$HOME/.kube/config`, and is generated
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by `cluster/kube-up.sh`. Sample steps for sharing `kubeconfig` below.
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**1. Create a cluster**
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{% highlight console %}
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{% raw %}
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$ cluster/kube-up.sh
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{% endraw %}
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{% endhighlight %}
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**2. Copy `kubeconfig` to new host**
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{% highlight console %}
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{% raw %}
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$ scp $HOME/.kube/config user@remotehost:/path/to/.kube/config
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{% endraw %}
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{% endhighlight %}
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**3. On new host, make copied `config` available to `kubectl`**
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* Option A: copy to default location
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{% highlight console %}
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{% raw %}
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$ mv /path/to/.kube/config $HOME/.kube/config
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{% endraw %}
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{% endhighlight %}
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* Option B: copy to working directory (from which kubectl is run)
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{% highlight console %}
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{% raw %}
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$ mv /path/to/.kube/config $PWD
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{% endraw %}
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{% endhighlight %}
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* Option C: manually pass `kubeconfig` location to `kubectl`
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{% highlight console %}
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{% raw %}
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# via environment variable
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$ export KUBECONFIG=/path/to/.kube/config
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# via commandline flag
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$ kubectl ... --kubeconfig=/path/to/.kube/config
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{% endraw %}
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{% endhighlight %}
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## Manually Generating `kubeconfig`
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`kubeconfig` is generated by `kube-up` but you can generate your own
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using (any desired subset of) the following commands.
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{% highlight console %}
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{% raw %}
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# create kubeconfig entry
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$ kubectl config set-cluster $CLUSTER_NICK \
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--server=https://1.1.1.1 \
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--certificate-authority=/path/to/apiserver/ca_file \
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--embed-certs=true \
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# Or if tls not needed, replace --certificate-authority and --embed-certs with
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--insecure-skip-tls-verify=true \
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--kubeconfig=/path/to/standalone/.kube/config
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# create user entry
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$ kubectl config set-credentials $USER_NICK \
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# bearer token credentials, generated on kube master
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--token=$token \
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# use either username|password or token, not both
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--username=$username \
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--password=$password \
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--client-certificate=/path/to/crt_file \
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--client-key=/path/to/key_file \
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--embed-certs=true \
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--kubeconfig=/path/to/standalone/.kube/config
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# create context entry
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$ kubectl config set-context $CONTEXT_NAME --cluster=$CLUSTER_NICKNAME --user=$USER_NICK
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{% endraw %}
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{% endhighlight %}
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Notes:
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* The `--embed-certs` flag is needed to generate a standalone
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`kubeconfig`, that will work as-is on another host.
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* `--kubeconfig` is both the preferred file to load config from and the file to
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save config too. In the above commands the `--kubeconfig` file could be
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omitted if you first run
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{% highlight console %}
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{% raw %}
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$ export KUBECONFIG=/path/to/standalone/.kube/config
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{% endraw %}
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{% endhighlight %}
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* The ca_file, key_file, and cert_file referenced above are generated on the
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kube master at cluster turnup. They can be found on the master under
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`/srv/kubernetes`. Bearer token/basic auth are also generated on the kube master.
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For more details on `kubeconfig` see [kubeconfig-file.md](kubeconfig-file.html),
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and/or run `kubectl config -h`.
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## Merging `kubeconfig` Example
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`kubectl` loads and merges config from the following locations (in order)
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1. `--kubeconfig=/path/to/.kube/config` command line flag
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2. `KUBECONFIG=/path/to/.kube/config` env variable
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3. `$PWD/.kube/config`
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4. `$HOME/.kube/config`
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If you create clusters A, B on host1, and clusters C, D on host2, you can
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make all four clusters available on both hosts by running
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{% highlight console %}
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{% raw %}
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# on host2, copy host1's default kubeconfig, and merge it from env
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$ scp host1:/path/to/home1/.kube/config /path/to/other/.kube/config
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$ export $KUBECONFIG=/path/to/other/.kube/config
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# on host1, copy host2's default kubeconfig and merge it from env
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$ scp host2:/path/to/home2/.kube/config /path/to/other/.kube/config
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$ export $KUBECONFIG=/path/to/other/.kube/config
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{% endraw %}
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{% endhighlight %}
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Detailed examples and explanation of `kubeconfig` loading/merging rules can be found in [kubeconfig-file.md](kubeconfig-file.html).
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<!-- BEGIN MUNGE: IS_VERSIONED -->
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<!-- TAG IS_VERSIONED -->
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<!-- END MUNGE: IS_VERSIONED -->
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<!-- BEGIN MUNGE: GENERATED_ANALYTICS -->
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[]()
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<!-- END MUNGE: GENERATED_ANALYTICS -->
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