[Kubelet] Use the custom mounter script for Nfs and Glusterfs only

cluster/gce/gci/configure-helper.sh

@@ -473,6 +473,7 @@ function start-kubelet {
   flags+=" --cluster-dns=${DNS_SERVER_IP}"
   flags+=" --cluster-domain=${DNS_DOMAIN}"
   flags+=" --config=/etc/kubernetes/manifests"
+  flags+=" --experimental-mounter-path=${KUBE_HOME}/bin/mounter"
 
   if [[ -n "${KUBELET_PORT:-}" ]]; then
     flags+=" --port=${KUBELET_PORT}"
@@ -1171,6 +1172,10 @@ function override-kubectl {
     echo "export PATH=${KUBE_HOME}/bin:\$PATH" > /etc/profile.d/kube_env.sh
 }
 
+function pre-warm-mounter {
+    ${KUBE_HOME}/bin/mounter &> /dev/null
+}
+
 ########### Main Function ###########
 echo "Start to configure instance for kubernetes"
 
@@ -1205,6 +1210,8 @@ else
 fi
 
 override-kubectl
+# Run the containerized mounter once to pre-cache the container image.
+pre-warm-mounter
 assemble-docker-flags
 load-docker-images
 start-kubelet

cluster/gce/gci/mounter/mounter

@@ -23,14 +23,25 @@ MOUNTER_USER=root
 RKT_BINARY=/home/kubernetes/bin/rkt
 
 function gc {
-    ${RKT_BINARY} gc --grace-period=0s &> /dev/null
+    # Attempt to garbage collect rkt pods with 5 retries.
+    # Rkt pods end up creating new copies of mounts on the host. Hence it is ideal to clean them up right away.
+    attempt=0
+    until [ $attempt -ge 5 ]; do
+	${RKT_BINARY} gc --grace-period=0s && break
+	attempt=$[$attempt+1]
+	sleep 1
+    done
 }
 
 # Garbage collect old rkt containers on exit
 trap gc EXIT
 
+echo "Running mount using a rkt fly container"
+
 ${RKT_BINARY} run --stage1-name="coreos.com/rkt/stage1-fly:1.18.0" \
 	--insecure-options=image \
-	--volume=rootfs,kind=host,source=/,readOnly=false,recursive=true \
-	--mount volume=rootfs,target=/media/root \
+	--volume=kubelet,kind=host,source=/var/lib/kubelet,readOnly=false,recursive=true \
+	--mount volume=kubelet,target=/var/lib/kubelet \
 	docker://${MOUNTER_DOCKER_IMAGE}:${MOUNTER_DOCKER_VERSION} --user=${MOUNTER_USER} --exec /bin/mount -- "$@"
+
+echo "Successfully ran mount using a rkt fly container"

cmd/kube-proxy/app/conntrack.go

@@ -67,7 +67,7 @@ func (realConntracker) SetTCPEstablishedTimeout(seconds int) error {
 func isSysFSWritable() (bool, error) {
 	const permWritable = "rw"
 	const sysfsDevice = "sysfs"
-	m := mount.New()
+	m := mount.New("" /* default mount path */)
 	mountPoints, err := m.List()
 	if err != nil {
 		glog.Errorf("failed to list mount points: %v", err)

cmd/kubelet/app/options/options.go

@@ -200,7 +200,6 @@ func (s *KubeletServer) AddFlags(fs *pflag.FlagSet) {
 	fs.BoolVar(&s.ExitOnLockContention, "exit-on-lock-contention", s.ExitOnLockContention, "Whether kubelet should exit upon lock-file contention.")
 	fs.StringVar(&s.RktPath, "rkt-path", s.RktPath, "Path of rkt binary. Leave empty to use the first rkt in $PATH.  Only used if --container-runtime='rkt'.")
 	fs.StringVar(&s.ExperimentalMounterPath, "experimental-mounter-path", s.ExperimentalMounterPath, "[Experimental] Path of mounter binary. Leave empty to use the default mount.")
-	fs.StringVar(&s.ExperimentalMounterRootfsPath, "experimental-mounter-rootfs-path", s.ExperimentalMounterRootfsPath, "[Experimental] Absolute path to the root filesystem for the mounter binary.")
 	fs.StringVar(&s.RktAPIEndpoint, "rkt-api-endpoint", s.RktAPIEndpoint, "The endpoint of the rkt API service to communicate with. Only used if --container-runtime='rkt'.")
 	fs.StringVar(&s.RktStage1Image, "rkt-stage1-image", s.RktStage1Image, "image to use as stage1. Local paths and http/https URLs are supported. If empty, the 'stage1.aci' in the same directory as '--rkt-path' will be used.")
 	fs.MarkDeprecated("rkt-stage1-image", "Will be removed in a future version. The default stage1 image will be specified by the rkt configurations, see https://github.com/coreos/rkt/blob/master/Documentation/configuration.md for more details.")

cmd/kubelet/app/server.go

@@ -118,7 +118,7 @@ func UnsecuredKubeletDeps(s *options.KubeletServer) (*kubelet.KubeletDeps, error
 		return nil, err
 	}
 
-	mounter := mount.NewCustomMounter(s.ExperimentalMounterPath, s.ExperimentalMounterRootfsPath)
+	mounter := mount.New(s.ExperimentalMounterPath)
 	var writer kubeio.Writer = &kubeio.StdWriter{}
 	if s.Containerized {
 		glog.V(2).Info("Running kubelet in containerized mode (experimental)")

docs/user-guide/kubectl/kubectl_cp.md

@@ -1,32 +1,3 @@
-<!-- BEGIN MUNGE: UNVERSIONED_WARNING -->
-
-<!-- BEGIN STRIP_FOR_RELEASE -->
-
-<img src="http://kubernetes.io/kubernetes/img/warning.png" alt="WARNING"
-     width="25" height="25">
-<img src="http://kubernetes.io/kubernetes/img/warning.png" alt="WARNING"
-     width="25" height="25">
-<img src="http://kubernetes.io/kubernetes/img/warning.png" alt="WARNING"
-     width="25" height="25">
-<img src="http://kubernetes.io/kubernetes/img/warning.png" alt="WARNING"
-     width="25" height="25">
-<img src="http://kubernetes.io/kubernetes/img/warning.png" alt="WARNING"
-     width="25" height="25">
-
-<h2>PLEASE NOTE: This document applies to the HEAD of the source tree</h2>
-
-If you are using a released version of Kubernetes, you should
-refer to the docs that go with that version.
-
-Documentation for other releases can be found at
-[releases.k8s.io](http://releases.k8s.io).
-</strong>
---
-
-<!-- END STRIP_FOR_RELEASE -->
-
-<!-- END MUNGE: UNVERSIONED_WARNING -->
-
 This file is autogenerated, but we've stopped checking such files into the
 repository to reduce the need for rebases. Please run hack/generate-docs.sh to
 populate this file.

hack/verify-flags/known-flags.txt

@@ -188,7 +188,6 @@ experimental-allowed-unsafe-sysctls
 experimental-bootstrap-kubeconfig
 experimental-keystone-url
 experimental-mounter-path
-experimental-mounter-rootfs-path
 experimental-nvidia-gpus
 experimental-prefix
 experimental-runtime-integration-type