Merge pull request #1290 from nikhiljindal/replicaSetDoc

federation: Adding user guides for federation replicasets and secrets

docs/user-guide/federation/index.md

@@ -34,11 +34,13 @@ and cloud providers.
 
 Once we have the control plane setup, we can start creating federation API
 resources.
-Following guides explain some of the resources in detail:
+The following guides explain some of the resources in detail:
 
-* [Services](/docs/user-guide/federation/federated-services/)
 * [Events](/docs/user-guide/federation/events/)
 * [Namespaces](/docs/user-guide/federation/namespaces/)
+* [ReplicaSets](/docs/user-guide/federation/replicasets/)
+* [Secrets](/docs/user-guide/federation/secrets/)
+* [Services](/docs/user-guide/federation/federated-services/)
 <!-- TODO: Add more guides here -->
 
 [API reference docs](/federation/docs/api-reference/readme/) lists all the

docs/user-guide/federation/replicasets.md

@@ -0,0 +1,105 @@
+---
+---
+
+This guide explains how to use replica sets in the Federation control plane.
+
+
+* TOC
+{:toc}
+
+## Prerequisites
+
+This guide assumes that you have a running Kubernetes Cluster
+Federation installation. If not, then head over to the
+[federation admin guide](/docs/admin/federation/) to learn how to
+bring up a cluster federation (or have your cluster administrator do
+this for you). Other tutorials, for example
+[this one](https://github.com/kelseyhightower/kubernetes-cluster-federation)
+by Kelsey Hightower, are also available to help you.
+
+You are also expected to have a basic
+[working knowledge of Kubernetes](/docs/getting-started-guides/) in
+general and [ReplicaSets](/docs/user-guide/replicasets/) in particular.
+
+## Overview
+
+Replica Sets in federation control plane (referred to as "federated replica sets" in
+this guide) are very similar to the traditional [Kubernetes
+ReplicaSets](/docs/user-guide/replicasets/), and provide the same functionality.
+Creating them in the federation control plane ensures that the desired number of
+replicas exist across the registered clusters.
+
+
+## Creating a Federated Replica Set
+
+The API for Federated Replica Set is 100% compatible with the
+API for traditional Kubernetes Replica Set. You can create a replica set by sending
+a request to the federation apiserver.
+
+You can do that using [kubectl](/docs/user-guide/kubectl/kubectl/) by running:
+
+``` shell
+kubectl --context=federation-cluster create -f myrs.yaml
+```
+
+The '--context=federation-cluster' flag tells kubectl to submit the
+request to the Federation apiserver instead of sending it to a kubernetes
+cluster.
+
+Once a federated replica set is created, the federation control plane will create
+a replica set in all underlying kubernetes clusters.
+You can verify this by checking each of the underlying clusters, for example:
+
+``` shell
+kubectl --context=gce-asia-east1a get rs myrs
+```
+
+The above assumes that you have a context named 'gce-asia-east1a'
+configured in your client for your cluster in that zone.
+
+These replica sets in underlying clusters will match the federation replica set
+except in the number of replicas. Federation control plane will ensure that the
+sum of replicas in each cluster match the desired number of replicas in the
+federation replica set.
+
+### Spreading Replicas in Underlying Clusters
+
+By default, replicas are spread equally in all the underlying clusters. For ex:
+if you have 3 registered clusters and you create a federated replica set with
+`spec.replicas = 9`, then each replica set in the 3 clusters will have
+`spec.replicas=3`.
+To modify the number of replicas in each cluster, you can specify
+[FederatedReplicaSetPreference](https://github.com/kubernetes/kubernetes/blob/{{page.githubbranch}}/federation/apis/federation/types.go)
+as an annotation with key `federation.kubernetes.io/replica-set-preferences`
+on federated replica set.
+
+
+## Updating a Federated Replica Set
+
+You can update a federated replica set as you would update a Kubernetes
+replica set; however, for a federated replica set, you must send the request to
+the federation apiserver instead of sending it to a specific Kubernetes cluster.
+The Federation control plan ensures that whenever the federated replica set is
+updated, it updates the corresponding replica sets in all underlying clusters to
+match it.
+If your update includes a change in number of replicas, the federation
+control plane will change the number of replicas in underlying clusters to
+ensure that their sum remains equal to the number of desired replicas in
+federated replica set.
+
+## Deleting a Federated Replica Set
+
+You can delete a federated replica set as you would delete a Kubernetes
+replica set; however, for a federated replica set, you must send the request to
+the federation apiserver instead of sending it to a specific Kubernetes cluster.
+
+For example, you can do that using kubectl by running:
+
+```shell
+kubectl --context=federation-cluster delete rs myrs
+```
+
+Note that at this point, deleting a federated replica set will not delete the
+corresponding replica sets from underlying clusters.
+You must delete the underlying Replica Sets manually.
+We intend to fix this in the future.

docs/user-guide/federation/secrets.md

@@ -0,0 +1,87 @@
+---
+---
+
+This guide explains how to use secrets in Federation control plane.
+
+
+* TOC
+{:toc}
+
+## Prerequisites
+
+This guide assumes that you have a running Kubernetes Cluster
+Federation installation. If not, then head over to the
+[federation admin guide](/docs/admin/federation/) to learn how to
+bring up a cluster federation (or have your cluster administrator do
+this for you). Other tutorials, for example
+[this one](https://github.com/kelseyhightower/kubernetes-cluster-federation)
+by Kelsey Hightower, are also available to help you.
+
+You are also expected to have a basic
+[working knowledge of Kubernetes](/docs/getting-started-guides/) in
+general and [Secrets](/docs/user-guide/secrets/) in particular.
+
+## Overview
+
+Secrets in federation control plane (referred to as "federated secrets" in
+this guide) are very similar to the traditional [Kubernetes
+Secrets](/docs/user-guide/secrets/) providing the same functionality.
+Creating them in the federation control plane ensures that they are synchronized
+across all the clusters in federation.
+
+
+## Creating a Federated Secret
+
+The API for Federated Secret is 100% compatible with the
+API for traditional Kubernetes Secret. You can create a secret by sending
+a request to the federation apiserver.
+
+You can do that using [kubectl](/docs/user-guide/kubectl/kubectl/) by running:
+
+``` shell
+kubectl --context=federation-cluster create -f mysecret.yaml
+```
+
+The '--context=federation-cluster' flag tells kubectl to submit the
+request to the Federation apiserver instead of sending it to a kubernetes
+cluster.
+
+Once a federated secret is created, the federation control plane will create
+a matching secret in all underlying kubernetes clusters.
+You can verify this by checking each of the underlying clusters, for example:
+
+``` shell
+kubectl --context=gce-asia-east1a get rs myrs
+```
+
+The above assumes that you have a context named 'gce-asia-east1a'
+configured in your client for your cluster in that zone.
+
+These secrets in underlying clusters will match the federated secret.
+
+
+## Updating a Federated Secret
+
+You can update a federated secret as you would update a Kubernetes
+secret; however, for a federated secret, you must send the request to
+the federation apiserver instead of sending it to a specific Kubernetes cluster.
+The Federation control plan ensures that whenever the federated secret is
+updated, it updates the corresponding secrets in all underlying clusters to
+match it.
+
+## Deleting a Federated Secret
+
+You can delete a federated secret as you would delete a Kubernetes
+secret; however, for a federated secret, you must send the request to
+the federation apiserver instead of sending it to a specific Kubernetes cluster.
+
+For example, you can do that using kubectl by running:
+
+```shell
+kubectl --context=federation-cluster delete rs myrs
+```
+
+Note that at this point, deleting a federated secret will not delete the
+corresponding secrets from underlying clusters.
+You must delete the underlying secrets manually.
+We intend to fix this in the future.