Add missing kubeadm-flags.env on upgrade (#578)

lib/pharos/phases/migrate_worker.rb

@@ -32,13 +32,18 @@ def migrate_1_3?
       end
 
       def migrate_1_3
-        logger.info { 'Upgrade kubelet config for 1.10' }
+        logger.info { 'Upgrade kubelet config' }
 
         # use the new version of kubeadm to write out /var/lib/kubelet/config.yaml for new kubelet version to be installed
         # the kube master must be running, which is the case for upgrades
         host_configurer.upgrade_kubeadm(Pharos::KUBEADM_VERSION)
 
         @ssh.exec!("sudo /usr/local/bin/pharos-kubeadm-#{Pharos::KUBEADM_VERSION} upgrade node config --kubelet-version=v#{Pharos::KUBE_VERSION}")
+
+        kubeadm_flags = @ssh.file("/var/lib/kubelet/kubeadm-flags.env")
+        return if kubeadm_flags.exist?
+
+        kubeadm_flags.write('KUBELET_KUBEADM_ARGS=--cni-bin-dir=/opt/cni/bin --cni-conf-dir=/etc/cni/net.d --network-plugin=cni')
       end
     end
   end