Kubeadm installation for CentOs.

Kubernetes repo added for CentOs and installed kubeadm using yum.

Closes-Bug: #2041844
Change-Id: I08e591d616ebea772bd8d87b3c8ab194bce7fb5b

devstack/lib/kubernetes

@@ -10,13 +10,13 @@ function get_k8s_log_level {
 }
 
 function kubeadm_install {
-
+    if ! is_ubuntu && ! is_fedora; then
-    if ! is_ubuntu; then
         (>&2 echo "WARNING: kubeadm installation is not supported in this \
 distribution.")
         return
     fi
 
+    if is_ubuntu; then
         apt_get install apt-transport-https
         curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | \
             sudo apt-key add -
@@ -37,6 +37,26 @@ distribution.")
         echo "KUBELET_EXTRA_ARGS=--node-ip=$HOST_IP" | sudo tee -a \
             /etc/default/kubelet
         sudo systemctl daemon-reload && sudo systemctl restart kubelet
+    fi
+
+    if is_fedora; then
+        source /etc/os-release
+        os_VENDOR=$(echo $NAME | tr -d '[:space:]')
+        if [[ $os_VENDOR =~ "CentOS" ]]; then
+             cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo
+[kubernetes]
+name=Kubernetes
+baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
+enabled=1
+gpgcheck=1
+repo_gpgcheck=1
+gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg \
+https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
+EOF
+             sudo chmod 755 /etc/yum.repos.d/kubernetes.repo
+             sudo dnf install kubeadm -y
+        fi
+    fi
 }
 
 function kubeadm_init {