Add mount test image

contrib/for-tests/mount-tester/Dockerfile

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+# Copyright 2015 Google Inc. All rights reserved.
+#
+# 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 scratch
+ADD mt mt
+ENTRYPOINT ["/mt"]

contrib/for-tests/mount-tester/Makefile

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+all: push
+
+TAG = 0.1
+
+mt: mt.go
+	CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -ldflags '-w' ./mt.go
+
+image: mt
+	sudo docker build -t kubernetes/mounttest:$(TAG) .
+
+push: image
+	sudo docker push kubernetes/mounttest:$(TAG)
+
+clean:
+	rm -f mt

contrib/for-tests/mount-tester/mt.go

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+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+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.
+*/
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"syscall"
+)
+
+var (
+	fsTypePath           = ""
+	fileModePath         = ""
+	readFileContentPath  = ""
+	readWriteNewFilePath = ""
+)
+
+func init() {
+	flag.StringVar(&fsTypePath, "fs_type", "", "Path to print the fs type for")
+	flag.StringVar(&fileModePath, "file_mode", "", "Path to print the filemode of")
+	flag.StringVar(&readFileContentPath, "file_content", "", "Path to read the file content from")
+	flag.StringVar(&readWriteNewFilePath, "rw_new_file", "", "Path to write to and read from")
+}
+
+// This program performs some tests on the filesystem as dictated by the
+// flags passed by the user.
+func main() {
+	flag.Parse()
+
+	var (
+		err  error
+		errs = []error{}
+	)
+
+	err = fsType(fsTypePath)
+	if err != nil {
+		errs = append(errs, err)
+	}
+
+	err = readWriteNewFile(readWriteNewFilePath)
+	if err != nil {
+		errs = append(errs, err)
+	}
+
+	err = fileMode(fileModePath)
+	if err != nil {
+		errs = append(errs, err)
+	}
+
+	err = readFileContent(readFileContentPath)
+	if err != nil {
+		errs = append(errs, err)
+	}
+
+	if len(errs) != 0 {
+		os.Exit(1)
+	}
+
+	os.Exit(0)
+}
+
+// Defined by Linux (sys/statfs.h) - the type number for tmpfs mounts.
+const linuxTmpfsMagic = 0x01021994
+
+func fsType(path string) error {
+	if path == "" {
+		return nil
+	}
+
+	buf := syscall.Statfs_t{}
+	if err := syscall.Statfs(path, &buf); err != nil {
+		fmt.Printf("error from statfs(%q): %v", path, err)
+		return err
+	}
+
+	if buf.Type == linuxTmpfsMagic {
+		fmt.Printf("mount type of %q: tmpfs\n", path)
+	} else {
+		fmt.Printf("mount type of %q: %v\n", path, buf.Type)
+	}
+
+	return nil
+}
+
+func fileMode(path string) error {
+	if path == "" {
+		return nil
+	}
+
+	fileinfo, err := os.Lstat(path)
+	if err != nil {
+		fmt.Printf("error from Lstat(%q): %v\n", path, err)
+		return err
+	}
+
+	fmt.Printf("mode of file %q: %v\n", path, fileinfo.Mode())
+	return nil
+}
+
+func readFileContent(path string) error {
+	if path == "" {
+		return nil
+	}
+
+	contentBytes, err := ioutil.ReadFile(path)
+	if err != nil {
+		fmt.Printf("error reading file content for %q: %v\n", path, err)
+		return err
+	}
+
+	fmt.Printf("content of file %q: %v\n", path, string(contentBytes))
+
+	return nil
+}
+
+func readWriteNewFile(path string) error {
+	if path == "" {
+		return nil
+	}
+
+	content := "mount-tester new file\n"
+	err := ioutil.WriteFile(path, []byte(content), 0644)
+	if err != nil {
+		fmt.Printf("error writing new file %q: %v\n", path, err)
+		return err
+	}
+
+	return readFileContent(path)
+}