Merge pull request #8752 from ZJU-SEL/Fix#8373

Fix #8373 add kubectl for cluster validation

cluster/ubuntu/build.sh

@@ -66,5 +66,7 @@ cp kubernetes/server/kubernetes/server/bin/kube-apiserver \
 cp kubernetes/server/kubernetes/server/bin/kubelet \
    kubernetes/server/kubernetes/server/bin/kube-proxy binaries/minion
 
+cp kubernetes/server/kubernetes/server/bin/kubectl binaries/
+
 rm -rf flannel* kubernetes* etcd*
 echo "Done! All your commands locate in ./binaries dir"

cluster/ubuntu/util.sh

@@ -26,6 +26,8 @@ MASTER=""
 MASTER_IP=""
 MINION_IPS=""
 
+KUBECTL_PATH=${KUBE_ROOT}/cluster/ubuntu/binaries/kubectl
+
 # Assumed Vars:
 #   KUBE_ROOT
 function test-build-release {

docs/getting-started-guides/ubuntu.md

@@ -92,7 +92,7 @@ If all things goes right, you will see the below message from console
 
 **All done !**
 
-You can also use kubectl command to see if the newly created k8s is working correctly. 
+You can also use `kubectl` command to see if the newly created k8s is working correctly. The `kubectl` binary is under the `cluster/ubuntu/binaries` directory. You can move it into your PATH. Then you can use the below command smoothly. 
 
 For example, use `$ kubectl get minions` to see if you get all your minion nodes comming up and ready. It may take some times for the minions be ready to use like below.