PLEASE NOTE: This document applies to the HEAD of the source tree
If you are using a released version of Kubernetes, you should
refer to the docs that go with that version.
The latest 1.0.x release of this document can be found
[here](http://releases.k8s.io/release-1.0/docs/user-guide/sharing-clusters.md).
Documentation for other releases can be found at
[releases.k8s.io](http://releases.k8s.io).
--
# Sharing Cluster Access
Client access to a running Kubernetes cluster can be shared by copying
the `kubectl` client config bundle ([.kubeconfig](kubeconfig-file.md)).
This config bundle lives in `$HOME/.kube/config`, and is generated
by `cluster/kube-up.sh`. Sample steps for sharing `kubeconfig` below.
**1. Create a cluster**
```console
$ cluster/kube-up.sh
```
**2. Copy `kubeconfig` to new host**
```console
$ scp $HOME/.kube/config user@remotehost:/path/to/.kube/config
```
**3. On new host, make copied `config` available to `kubectl`**
* Option A: copy to default location
```console
$ mv /path/to/.kube/config $HOME/.kube/config
```
* Option B: copy to working directory (from which kubectl is run)
```console
$ mv /path/to/.kube/config $PWD
```
* Option C: manually pass `kubeconfig` location to `.kubectl`
```console
# via environment variable
$ export KUBECONFIG=/path/to/.kube/config
# via commandline flag
$ kubectl ... --kubeconfig=/path/to/.kube/config
```
## Manually Generating `kubeconfig`
`kubeconfig` is generated by `kube-up` but you can generate your own
using (any desired subset of) the following commands.
```console
# create kubeconfig entry
$ kubectl config set-cluster $CLUSTER_NICK \
--server=https://1.1.1.1 \
--certificate-authority=/path/to/apiserver/ca_file \
--embed-certs=true \
# Or if tls not needed, replace --certificate-authority and --embed-certs with
--insecure-skip-tls-verify=true \
--kubeconfig=/path/to/standalone/.kube/config
# create user entry
$ kubectl config set-credentials $USER_NICK \
# bearer token credentials, generated on kube master
--token=$token \
# use either username|password or token, not both
--username=$username \
--password=$password \
--client-certificate=/path/to/crt_file \
--client-key=/path/to/key_file \
--embed-certs=true \
--kubeconfig=/path/to/standalone/.kubeconfig
# create context entry
$ kubectl config set-context $CONTEXT_NAME --cluster=$CLUSTER_NICKNAME --user=$USER_NICK
```
Notes:
* The `--embed-certs` flag is needed to generate a standalone
`kubeconfig`, that will work as-is on another host.
* `--kubeconfig` is both the preferred file to load config from and the file to
save config too. In the above commands the `--kubeconfig` file could be
omitted if you first run
```console
$ export KUBECONFIG=/path/to/standalone/.kube/config
```
* The ca_file, key_file, and cert_file referenced above are generated on the
kube master at cluster turnup. They can be found on the master under
`/srv/kubernetes`. Bearer token/basic auth are also generated on the kube master.
For more details on `kubeconfig` see [kubeconfig-file.md](kubeconfig-file.md),
and/or run `kubectl config -h`.
## Merging `kubeconfig` Example
`kubectl` loads and merges config from the following locations (in order)
1. `--kubeconfig=path/to/.kube/config` commandline flag
2. `KUBECONFIG=path/to/.kube/config` env variable
3. `$PWD/.kubeconfig`
4. `$HOME/.kube/config`
If you create clusters A, B on host1, and clusters C, D on host2, you can
make all four clusters available on both hosts by running
```console
# on host2, copy host1's default kubeconfig, and merge it from env
$ scp host1:/path/to/home1/.kube/config path/to/other/.kube/config
$ export $KUBECONFIG=path/to/other/.kube/config
# on host1, copy host2's default kubeconfig and merge it from env
$ scp host2:/path/to/home2/.kube/config path/to/other/.kube/config
$ export $KUBECONFIG=path/to/other/.kube/config
```
Detailed examples and explanation of `kubeconfig` loading/merging rules can be found in [kubeconfig-file.md](kubeconfig-file.md).
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