Update docker and docker-multinode docs on master to require 1.2.x and use the hyperkube-arch image

docs/getting-started-guides/docker-multinode/worker.md

@@ -38,13 +38,13 @@ Documentation for other releases can be found at
 These instructions are very similar to the master set-up above, but they are duplicated for clarity.
 You need to repeat these instructions for each node you want to join the cluster.
 We will assume that you have the IP address of the master in `${MASTER_IP}` that you created in the [master instructions](master.md).  We'll need to run several versioned Kubernetes components, so we'll assume that the version we want
-to run is `${K8S_VERSION}`, which should hold a value such as "1.1.3".
+to run is `${K8S_VERSION}`, which should hold a released version of Kubernetes >= "1.2.0-alpha.6"
 
 Enviroinment variables used:
 
 ```sh
 export MASTER_IP=<the_master_ip_here>
-export K8S_VERSION=<your_k8s_version (e.g. 1.1.3)>
+export K8S_VERSION=<your_k8s_version (e.g. 1.2.0-alpha.6)>
 export FLANNEL_VERSION=<your_flannel_version (e.g. 0.5.5)>
 export FLANNEL_IFACE=<flannel_interface (defaults to eth0)>
 ```
@@ -174,7 +174,7 @@ sudo docker run \
     --privileged=true \
     --pid=host \ 
     -d \
-    gcr.io/google_containers/hyperkube:v${K8S_VERSION} \
+    gcr.io/google_containers/hyperkube-amd64:v${K8S_VERSION} \
     /hyperkube kubelet \
         --allow-privileged=true \
         --api-servers=http://${MASTER_IP}:8080 \
@@ -194,7 +194,7 @@ The service proxy provides load-balancing between groups of containers defined b
 sudo docker run -d \
     --net=host \
     --privileged \
-    gcr.io/google_containers/hyperkube:v${K8S_VERSION} \
+    gcr.io/google_containers/hyperkube-amd64:v${K8S_VERSION} \
     /hyperkube proxy \
         --master=http://${MASTER_IP}:8080 \
         --v=2