lib/fs: add MustStopDirRemover for waiting until pending directories are removed on graceful shutdown

This patch is mainly required for laggy NFS. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/162
This commit is contained in:
Aliaksandr Valialkin 2019-09-05 11:12:02 +03:00
parent 9eb5de334f
commit 88f8670ede
4 changed files with 123 additions and 70 deletions

View file

@ -9,6 +9,7 @@ import (
"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect"
"github.com/VictoriaMetrics/VictoriaMetrics/app/vmstorage"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/buildinfo"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/fs"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/httpserver"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/procutil"
@ -43,6 +44,8 @@ func main() {
vmstorage.Stop()
vmselect.Stop()
fs.MustStopDirRemover()
logger.Infof("the VictoriaMetrics has been stopped in %s", time.Since(startTime))
}

View file

@ -21,6 +21,7 @@ import (
"github.com/VictoriaMetrics/VictoriaMetrics/app/vminsert"
"github.com/VictoriaMetrics/VictoriaMetrics/app/vmselect"
"github.com/VictoriaMetrics/VictoriaMetrics/app/vmstorage"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/fs"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/httpserver"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
)
@ -92,7 +93,7 @@ func setUp() {
func processFlags() {
flag.Parse()
for _, fs := range []struct {
for _, fv := range []struct {
flag string
value string
}{
@ -103,8 +104,8 @@ func processFlags() {
{flag: "loggerLevel", value: testLogLevel},
} {
// panics if flag doesn't exist
if err := flag.Lookup(fs.flag).Value.Set(fs.value); err != nil {
log.Fatalf("unable to set %q with value %q, err: %v", fs.flag, fs.value, err)
if err := flag.Lookup(fv.flag).Value.Set(fv.value); err != nil {
log.Fatalf("unable to set %q with value %q, err: %v", fv.flag, fv.value, err)
}
}
}
@ -121,13 +122,14 @@ func waitFor(timeout time.Duration, f func() bool) error {
}
func tearDown() {
vminsert.Stop()
vmstorage.Stop()
vmselect.Stop()
if err := httpserver.Stop(*httpListenAddr); err != nil {
log.Fatalf("cannot stop the webservice: %s", err)
}
os.RemoveAll(storagePath)
vminsert.Stop()
vmstorage.Stop()
vmselect.Stop()
fs.MustRemoveAll(storagePath)
fs.MustStopDirRemover()
}
func TestWriteRead(t *testing.T) {

111
lib/fs/dir_remover.go Normal file
View file

@ -0,0 +1,111 @@
package fs
import (
"os"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/metrics"
)
func mustRemoveAll(path string) bool {
err := os.RemoveAll(path)
if err == nil {
// Make sure the parent directory doesn't contain references
// to the current directory.
mustSyncParentDirIfExists(path)
return true
}
if !isTemporaryNFSError(err) {
logger.Panicf("FATAL: cannot remove %q: %s", path, err)
}
// NFS prevents from removing directories with open files.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/61 .
// Schedule for later directory removal.
nfsDirRemoveFailedAttempts.Inc()
select {
case removeDirCh <- path:
default:
logger.Panicf("FATAL: cannot schedule %s for removal, since the removal queue is full (%d entries)", path, cap(removeDirCh))
}
return false
}
var nfsDirRemoveFailedAttempts = metrics.NewCounter(`vm_nfs_dir_remove_failed_attempts_total`)
var removeDirCh = make(chan string, 1024)
func dirRemover() {
const minSleepTime = 100 * time.Millisecond
const maxSleepTime = time.Second
sleepTime := minSleepTime
for {
var path string
select {
case path = <-removeDirCh:
default:
if atomic.LoadUint64(&stopDirRemover) != 0 {
return
}
time.Sleep(minSleepTime)
continue
}
if mustRemoveAll(path) {
sleepTime = minSleepTime
continue
}
// Couldn't remove the directory at the path because of NFS lock.
// Sleep for a while and try again.
// Do not limit the amount of time required for deleting the directory,
// since this may break on laggy NFS.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/162 .
time.Sleep(sleepTime)
if sleepTime < maxSleepTime {
sleepTime *= 2
} else {
logger.Errorf("failed to remove directory %q due to NFS lock; retrying later", path)
}
}
}
func isTemporaryNFSError(err error) bool {
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/61 for details.
errStr := err.Error()
return strings.Contains(errStr, "directory not empty") || strings.Contains(errStr, "device or resource busy")
}
var dirRemoverWG sync.WaitGroup
var stopDirRemover uint64
func init() {
dirRemoverWG.Add(1)
go func() {
defer dirRemoverWG.Done()
dirRemover()
}()
}
// MustStopDirRemover must be called in the end of graceful shutdown
// in order to wait for removing the remaining directories from removeDirCh.
//
// It is expected that nobody calls MustRemoveAll when MustStopDirRemover
// is called.
func MustStopDirRemover() {
atomic.StoreUint64(&stopDirRemover, 1)
doneCh := make(chan struct{})
go func() {
dirRemoverWG.Wait()
close(doneCh)
}()
const maxWaitTime = 5 * time.Second
select {
case <-doneCh:
return
case <-time.After(maxWaitTime):
logger.Panicf("FATAL: cannot stop dirRemover in %s", maxWaitTime)
}
}

View file

@ -6,9 +6,7 @@ import (
"os"
"path/filepath"
"regexp"
"strings"
"sync/atomic"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/filestream"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
@ -251,67 +249,6 @@ func MustRemoveAll(path string) {
_ = mustRemoveAll(path)
}
func mustRemoveAll(path string) bool {
err := os.RemoveAll(path)
if err == nil {
// Make sure the parent directory doesn't contain references
// to the current directory.
mustSyncParentDirIfExists(path)
return true
}
if !isTemporaryNFSError(err) {
logger.Panicf("FATAL: cannot remove %q: %s", path, err)
}
// NFS prevents from removing directories with open files.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/61 .
// Schedule for later directory removal.
nfsDirRemoveFailedAttempts.Inc()
select {
case removeDirCh <- path:
default:
logger.Panicf("FATAL: cannot schedule %s for removal, since the removal queue is full (%d entries)", path, cap(removeDirCh))
}
return false
}
var nfsDirRemoveFailedAttempts = metrics.NewCounter(`vm_nfs_dir_remove_failed_attempts_total`)
var removeDirCh = make(chan string, 1024)
func dirRemover() {
const minSleepTime = 100 * time.Millisecond
const maxSleepTime = time.Second
sleepTime := minSleepTime
for path := range removeDirCh {
if mustRemoveAll(path) {
sleepTime = minSleepTime
continue
}
// Couldn't remove the directory at the path because of NFS lock.
// Sleep for a while and try again.
// Do not limit the amount of time required for deleting the directory,
// since this may break on laggy NFS.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/162 .
time.Sleep(sleepTime)
if sleepTime < maxSleepTime {
sleepTime *= 2
} else {
logger.Errorf("failed to remove directory %q due to NFS lock; retrying later", path)
}
}
}
func isTemporaryNFSError(err error) bool {
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/61 for details.
errStr := err.Error()
return strings.Contains(errStr, "directory not empty") || strings.Contains(errStr, "device or resource busy")
}
func init() {
go dirRemover()
}
// HardLinkFiles makes hard links for all the files from srcDir in dstDir.
func HardLinkFiles(srcDir, dstDir string) error {
if err := mkdirSync(dstDir); err != nil {