Adding dummy and dummy-attachable example Flexvolume drivers; adding DaemonSet deployment example

examples/volumes/flexvolume/deploy/Dockerfile

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+# Copyright 2018 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+FROM busybox
+WORKDIR .
+
+# TODO Change to your desired driver.
+COPY ./drivers/dummy /dummy
+
+COPY deploy.sh /deploy.sh
+CMD /bin/sh /deploy.sh

examples/volumes/flexvolume/deploy/README.md

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+This directory contains an example of the DaemonSet Flexvolume driver deployment method. See documentation [here](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/storage/flexvolume-deployment.md#recommended-driver-deployment-method).
+
+Steps to use the DaemonSet deployment method:
+1. Copy the Flexvolume driver to `drivers` directory. To get a basic example running, copy the `dummy` driver from the parent directory.
+1. If you'd like to just get a basic example running, you could skip this step. Otherwise, change the places marked with `TODO` in all files.
+1. Build the deployment Docker image and upload to your container registry.
+1. Create the DaemonSet.

examples/volumes/flexvolume/deploy/deploy.sh

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+#!/bin/sh
+
+# Copyright 2018 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -o errexit
+set -o pipefail
+
+# TODO change to your desired driver.
+VENDOR=${VENDOR:-k8s}
+DRIVER=${DRIVER:-dummy}
+
+# Assuming the single driver file is located at /$DRIVER inside the DaemonSet image.
+
+driver_dir=$VENDOR${VENDOR:+"~"}${DRIVER}
+if [ ! -d "/flexmnt/$driver_dir" ]; then
+  mkdir "/flexmnt/$driver_dir"
+fi
+
+tmp_driver=.tmp_$DRIVER
+cp "/$DRIVER" "/flexmnt/$driver_dir/$tmp_driver"
+mv -f "/flexmnt/$driver_dir/$tmp_driver" "/flexmnt/$driver_dir/$DRIVER"
+
+while : ; do
+  sleep 3600
+done

examples/volumes/flexvolume/deploy/ds.yaml

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+apiVersion: extensions/v1beta1
+kind: DaemonSet
+metadata:
+  name: flex-ds
+spec:
+  template:
+    metadata:
+      name: flex-deploy
+      labels:
+        app: flex-deploy
+    spec:
+      containers:
+        # TODO Change to your container registry.
+        - image: "<image_url>"
+          name: flex-deploy
+          securityContext:
+            privileged: true
+          volumeMounts:
+            - mountPath: /flexmnt
+              name: flexvolume-mount
+      volumes:
+        - name: flexvolume-mount
+          hostPath:
+            # TODO Change to the Flexvolume plugin directory of your cluster.
+            path: /usr/libexec/kubernetes/kubelet-plugins/volume/exec/

examples/volumes/flexvolume/dummy

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+#!/bin/sh
+
+# Copyright 2017 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This driver implements a tmpfs with a pre-populated file index.html.
+
+FLEX_DUMMY_LOG=${FLEX_DUMMY_LOG:-"/tmp/flex-dummy.log"}
+
+log() {
+	printf "$*" >&1
+}
+
+debug() {
+	echo "$(date) $*" >> "${FLEX_DUMMY_LOG}"
+}
+
+domount() {
+	debug "domount $@"
+	MNTPATH=$1
+	mkdir -p ${MNTPATH} >/dev/null 2>&1
+	mount -t tmpfs none ${MNTPATH} >/dev/null 2>&1
+	echo "Hello from flexvolume!" >> "${MNTPATH}/index.html"
+	log "{\"status\":\"Success\"}"
+	exit 0
+}
+
+unmount() {
+	debug "unmount $@"
+	MNTPATH=$1
+	rm ${MNTPATH}/index.html >/dev/null 2>&1
+	umount ${MNTPATH} >/dev/null 2>&1
+	log "{\"status\":\"Success\"}"
+	exit 0
+}
+
+op=$1
+
+if [ "$op" = "init" ]; then
+	debug "init $@"
+	log "{\"status\":\"Success\",\"capabilities\":{\"attach\":false}}"
+	exit 0
+fi
+
+shift
+
+case "$op" in
+	mount)
+		domount $*
+		;;
+	unmount)
+		unmount $*
+		;;
+	*)
+		log "{\"status\":\"Not supported\"}"
+		exit 0
+esac
+
+exit 1

examples/volumes/flexvolume/dummy-attachable

@@ -0,0 +1,126 @@
+#!/bin/sh
+
+# Copyright 2017 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This driver implements a tmpfs with a pre-populated file index.html.
+# Attach is required, but it is a no-op that always returns success.
+
+FLEX_DUMMY_LOG=${FLEX_DUMMY_LOG:-"/tmp/flex-dummy.log"}
+
+VALID_MNTDEVICE=foo
+
+# attach always returns one valid mount device so a different device
+# showing up in a subsequent driver call implies a bug
+validateMountDeviceOrDie() {
+	MNTDEVICE=$1
+	CALL=$2
+	if [ "$MNTDEVICE" != "$VALID_MNTDEVICE" ]; then
+		log "{\"status\":\"Failure\",\"message\":\"call "${CALL}" expected device "${VALID_MNTDEVICE}", got device "${MNTDEVICE}"\"}"
+		exit 0
+	fi
+}
+
+log() {
+	printf "$*" >&1
+}
+
+debug() {
+	echo "$(date) $*" >> "${FLEX_DUMMY_LOG}"
+}
+
+attach() {
+	debug "attach $@"
+	log "{\"status\":\"Success\",\"device\":\""${VALID_MNTDEVICE}"\"}"
+	exit 0
+}
+
+detach() {
+	debug "detach $@"
+	log "{\"status\":\"Success\"}"
+	exit 0
+}
+
+waitforattach() {
+	debug "waitforattach $@"
+	MNTDEVICE=$1
+	validateMountDeviceOrDie "$MNTDEVICE" "waitforattach"
+	log "{\"status\":\"Success\",\"device\":\""${MNTDEVICE}"\"}"
+	exit 0
+}
+
+isattached() {
+	debug "isattached $@"
+	log "{\"status\":\"Success\",\"attached\":true}"
+	exit 0
+}
+
+domountdevice() {
+	debug "domountdevice $@"
+	MNTDEVICE=$2
+	validateMountDeviceOrDie "$MNTDEVICE" "domountdevice"
+	MNTPATH=$1
+	mkdir -p ${MNTPATH} >/dev/null 2>&1
+	mount -t tmpfs none ${MNTPATH} >/dev/null 2>&1
+	echo "Hello from flexvolume!" >> "${MNTPATH}/index.html"
+	log "{\"status\":\"Success\"}"
+	exit 0
+}
+
+unmountdevice() {
+	debug "unmountdevice $@"
+	MNTDEVICE=$2
+	validateMountDeviceOrDie "$MNTDEVICE" "unmountdevice"
+	MNTPATH=$1
+	rm "${MNTPATH}/index.html" >/dev/null 2>&1
+	umount ${MNTPATH} >/dev/null 2>&1
+	log "{\"status\":\"Success\"}"
+	exit 0
+}
+
+op=$1
+
+if [ "$op" = "init" ]; then
+	debug "init $@"
+	log "{\"status\":\"Success\",\"capabilities\":{\"attach\":true}}"
+	exit 0
+fi
+
+shift
+
+case "$op" in
+	attach)
+		attach $*
+		;;
+	detach)
+		detach $*
+		;;
+	waitforattach)
+		waitforattach $*
+		;;
+	isattached)
+		isattached $*
+		;;
+	mountdevice)
+		domountdevice $*
+		;;
+	unmountdevice)
+		unmountdevice $*
+		;;
+	*)
+		log "{\"status\":\"Not supported\"}"
+		exit 0
+esac
+
+exit 1

examples/volumes/flexvolume/nginx-dummy-attachable.yaml

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+apiVersion: v1
+kind: Pod
+metadata:
+  name: nginx-dummy-attachable
+  namespace: default
+spec:
+  containers:
+  - name: nginx-dummy-attachable
+    image: nginx
+    volumeMounts:
+    - name: dummy-attachable
+      mountPath: /data
+    ports:
+    - containerPort: 80
+  volumes:
+  - name: dummy-attachable
+    flexVolume:
+      driver: "k8s/dummy-attachable"

examples/volumes/flexvolume/nginx-dummy.yaml

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+apiVersion: v1
+kind: Pod
+metadata:
+  name: nginx-dummy
+  namespace: default
+spec:
+  containers:
+  - name: nginx-dummy
+    image: nginx
+    volumeMounts:
+    - name: dummy
+      mountPath: /data
+    ports:
+    - containerPort: 80
+  volumes:
+  - name: dummy
+    flexVolume:
+      driver: "k8s/dummy"

test/e2e/testing-manifests/flexvolume/dummy

@@ -14,6 +14,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# This driver implements a tmpfs with a pre-populated file index.html.
+
 FLEX_DUMMY_LOG=${FLEX_DUMMY_LOG:-"/tmp/flex-dummy.log"}
 
 log() {

test/e2e/testing-manifests/flexvolume/dummy-attachable

@@ -14,6 +14,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# This driver implements a tmpfs with a pre-populated file index.html.
+# Attach is required, but it is a no-op that always returns success.
+
 FLEX_DUMMY_LOG=${FLEX_DUMMY_LOG:-"/tmp/flex-dummy.log"}
 
 VALID_MNTDEVICE=foo