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@ -14,11 +14,11 @@ This guide explains how to set up cluster federation that lets us control multip
## Prerequisites ## Prerequisites
This guide assumes that you have a running Kubernetes cluster. This guide assumes that you have a running Kubernetes cluster.
If not, then head over to the [getting started guides](/docs/getting-started-guides/) to bring up a cluster. If you need to start a new cluster, see the [getting started guides](/docs/getting-started-guides/) for instructions on bringing a cluster up.
This guide also assumes that you have a Kubernetes release To use the commands in this guide, you must download a Kubernetes release from the
[downloaded from here](/docs/getting-started-guides/binary_release/), [getting started binary releases](/docs/getting-started-guides/binary_release/) and
extracted into a directory and all the commands in this guide are run from extract into a directory; all the commands in this guide are run from
that directory. that directory.
```shell ```shell
@ -26,8 +26,8 @@ $ curl -L https://github.com/kubernetes/kubernetes/releases/download/v1.4.0/kube
$ cd kubernetes $ cd kubernetes
``` ```
This guide also assumes that you have an installation of Docker running You must also have a Docker installation running
locally, i.e. on the machine where you run the commands described in this locally--meaning on the machine where you run the commands described in this
guide. guide.
## Setting up a federation control plane ## Setting up a federation control plane
@ -212,24 +212,21 @@ cluster1 Ready 3m
## Updating KubeDNS ## Updating KubeDNS
Once the cluster is registered with the federation, you are all set to use it. Once you've registered your cluster with the federation, you'll need to update KubeDNS so that your cluster can route federation service requests. The update method varies depending on your Kubernetes version; on Kubernetes 1.5 or later, you must pass the
But for the cluster to be able to route federation service requests, you need to `--federations` flag to kube-dns via the kube-dns config map. In version 1.4 or earlier, you must set the `--federations` flag directly on kube-dns-rc on other clusters.
pass federation domain information to it. This can be done by passing the
`--federations` flag to kube-dns via kube-dns config map in a v1.5+ cluster and
setting the `--federations` flag directly on kube-dns-rc on other clusters.
### Passing federations flag via config map to kube-dns on v1.5+ cluster ### Kubernetes 1.5+: Passing federations flag via config map to kube-dns
For kubernetes clusters of version 1.5+, you can pass the For kubernetes clusters of version 1.5+, you can pass the
`--federations` flag to kube-dns via kube-dns config map. `--federations` flag to kube-dns via the kube-dns config map.
Format of the flag is like this: The flag uses the following format:
``` ```
--federations=${FEDERATION_NAME}=${DNS_DOMAIN_NAME} --federations=${FEDERATION_NAME}=${DNS_DOMAIN_NAME}
``` ```
To pass this flag to KubeDNS, create a config-map with name `kube-dns` in To pass this flag to KubeDNS, create a config-map with name `kube-dns` in
namespace `kube-system`. The configmap should look like: namespace `kube-system`. The configmap should look like the following:
```yaml ```yaml
apiVersion: v1 apiVersion: v1
@ -242,55 +239,54 @@ data:
``` ```
where `<federation-name>` should be replaced by the name you want to give to your where `<federation-name>` should be replaced by the name you want to give to your
federation; and federation, and
`federation-domain-name` should be replaced by the domain name you want to use `federation-domain-name` should be replaced by the domain name you want to use
in your federation DNS. in your federation DNS.
You can find more details about config maps in general at You can find more details about config maps in general at
http://kubernetes.io/docs/user-guide/configmap/. http://kubernetes.io/docs/user-guide/configmap/.
### Setting federations flag on kube-dns-rc on clusters before v1.5 ### Kubernetes 1.4 and earlier: Setting federations flag on kube-dns-rc
For kubernetes clusters of version less than v1.5, you need to restart If your cluster is running Kubernetes version 1.4 or earlier, you must to restart
KubeDNS and pass it a `--federations` flag which tells it about valid federation DNS hostnames. KubeDNS and pass it a `--federations` flag, which tells it about valid federation DNS hostnames.
Format of the flag is like this: The flag uses the following format:
``` ```
--federations=${FEDERATION_NAME}=${DNS_DOMAIN_NAME} --federations=${FEDERATION_NAME}=${DNS_DOMAIN_NAME}
``` ```
To update KubeDNS with federations flag, you can edit the existing kubedns replication controller to To update KubeDNS with the `--federations` flag, you can edit the existing kubedns replication controller to
include that flag in pod template spec and then delete the existing pod. Replication controller will include that flag in pod template spec, and then delete the existing pod. The replication controller then
recreate the pod with updated template. recreates the pod with updated template.
To find the name of existing kubedns replication controller, run To find the name of existing kubedns replication controller, run the following command:
```shell ```shell
$ kubectl get rc --namespace=kube-system $ kubectl get rc --namespace=kube-system
``` ```
This will list all the replication controllers. Name of the kube-dns replication You should see a list of all the replication controllers on the cluster. The kube-dns replication
controller will look like `kube-dns-v18`. You can then edit it by running: controller should have a name similar to `kube-dns-v18`. To edit the replication controller, specify it by name as follows:
```shell ```shell
$ kubectl edit rc <rc-name> --namespace=kube-system $ kubectl edit rc <rc-name> --namespace=kube-system
``` ```
Add the `--federations` flag as args to kube-dns container in the YAML file that In the resulting YAML file for the kube-dns replication controller, add the `--federations` flag as an argument to kube-dns container.
pops up after running the above command.
To delete the existing kube dns pod, you can first find it by running: Then, you must delete the existing kube dns pod. You can find the pod by running:
```shell ```shell
$ kubectl get pods --namespace=kube-system $ kubectl get pods --namespace=kube-system
``` ```
And then delete it by running: And then delete the appropriate pod by running:
```shell ```shell
$ kubectl delete pods <pod-name> --namespace=kube-system $ kubectl delete pods <pod-name> --namespace=kube-system
``` ```
You are now all set to start using federation. Once you've completed the kube-dns configuration, your federation is ready for use.
## Turn down ## Turn down