Merge pull request #100369 from wzshiming/fix/restart-dbus-for-graceful-node-shutdown

After DBus restarts, make GracefulNodeShutdown work again
This commit is contained in:
Kubernetes Prow Robot 2021-06-14 20:50:00 -07:00 committed by GitHub
commit 4e7fc6df63
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4 changed files with 134 additions and 20 deletions

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@ -24,7 +24,6 @@ import (
"sync"
"time"
"github.com/godbus/dbus/v5"
v1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/util/clock"
utilfeature "k8s.io/apiserver/pkg/util/feature"
@ -40,14 +39,11 @@ const (
nodeShutdownReason = "Shutdown"
nodeShutdownMessage = "Node is shutting, evicting pods"
nodeShutdownNotAdmitMessage = "Node is in progress of shutting down, not admitting any new pods"
dbusReconnectPeriod = 1 * time.Second
)
var systemDbus = func() (dbusInhibiter, error) {
bus, err := dbus.SystemBus()
if err != nil {
return nil, err
}
return &systemd.DBusCon{SystemBus: bus}, nil
return systemd.NewDBusCon()
}
type dbusInhibiter interface {
@ -109,55 +105,77 @@ func (m *Manager) Start() error {
if !m.isFeatureEnabled() {
return nil
}
systemBus, err := systemDbus()
stop, err := m.start()
if err != nil {
return err
}
go func() {
for {
if stop != nil {
<-stop
}
time.Sleep(dbusReconnectPeriod)
klog.V(1).InfoS("Restarting watch for node shutdown events")
stop, err = m.start()
if err != nil {
klog.ErrorS(err, "Unable to watch the node for shutdown events")
}
}
}()
return nil
}
func (m *Manager) start() (chan struct{}, error) {
systemBus, err := systemDbus()
if err != nil {
return nil, err
}
m.dbusCon = systemBus
currentInhibitDelay, err := m.dbusCon.CurrentInhibitDelay()
if err != nil {
return err
return nil, err
}
// If the logind's InhibitDelayMaxUSec as configured in (logind.conf) is less than shutdownGracePeriodRequested, attempt to update the value to shutdownGracePeriodRequested.
if m.shutdownGracePeriodRequested > currentInhibitDelay {
err := m.dbusCon.OverrideInhibitDelay(m.shutdownGracePeriodRequested)
if err != nil {
return fmt.Errorf("unable to override inhibit delay by shutdown manager: %w", err)
return nil, fmt.Errorf("unable to override inhibit delay by shutdown manager: %v", err)
}
err = m.dbusCon.ReloadLogindConf()
if err != nil {
return err
return nil, err
}
// Read the current inhibitDelay again, if the override was successful, currentInhibitDelay will be equal to shutdownGracePeriodRequested.
updatedInhibitDelay, err := m.dbusCon.CurrentInhibitDelay()
if err != nil {
return err
return nil, err
}
if updatedInhibitDelay != m.shutdownGracePeriodRequested {
return fmt.Errorf("node shutdown manager was unable to update logind InhibitDelayMaxSec to %v (ShutdownGracePeriod), current value of InhibitDelayMaxSec (%v) is less than requested ShutdownGracePeriod", m.shutdownGracePeriodRequested, updatedInhibitDelay)
return nil, fmt.Errorf("node shutdown manager was unable to update logind InhibitDelayMaxSec to %v (ShutdownGracePeriod), current value of InhibitDelayMaxSec (%v) is less than requested ShutdownGracePeriod", m.shutdownGracePeriodRequested, updatedInhibitDelay)
}
}
err = m.aquireInhibitLock()
if err != nil {
return err
return nil, err
}
events, err := m.dbusCon.MonitorShutdown()
if err != nil {
releaseErr := m.dbusCon.ReleaseInhibitLock(m.inhibitLock)
if releaseErr != nil {
return fmt.Errorf("failed releasing inhibitLock: %v and failed monitoring shutdown: %w", releaseErr, err)
return nil, fmt.Errorf("failed releasing inhibitLock: %v and failed monitoring shutdown: %v", releaseErr, err)
}
return fmt.Errorf("failed to monitor shutdown: %w", err)
return nil, fmt.Errorf("failed to monitor shutdown: %v", err)
}
stop := make(chan struct{})
go func() {
// Monitor for shutdown events. This follows the logind Inhibit Delay pattern described on https://www.freedesktop.org/wiki/Software/systemd/inhibit/
// 1. When shutdown manager starts, an inhibit lock is taken.
@ -165,7 +183,12 @@ func (m *Manager) Start() error {
// 3. When shutdown(false) event is received, this indicates a previous shutdown was cancelled. In this case, acquire the inhibit lock again.
for {
select {
case isShuttingDown := <-events:
case isShuttingDown, ok := <-events:
if !ok {
klog.ErrorS(err, "Ended to watching the node for shutdown events")
close(stop)
return
}
klog.V(1).InfoS("Shutdown manager detected new shutdown event, isNodeShuttingDownNow", "event", isShuttingDown)
m.nodeShuttingDownMutex.Lock()
@ -183,7 +206,7 @@ func (m *Manager) Start() error {
}
}
}()
return nil
return stop, nil
}
func (m *Manager) aquireInhibitLock() error {

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@ -93,6 +93,10 @@ func makePod(name string, criticalPod bool, terminationGracePeriod *int64) *v1.P
}
func TestManager(t *testing.T) {
systemDbusTmp := systemDbus
defer func() {
systemDbus = systemDbusTmp
}()
normalPodNoGracePeriod := makePod("normal-pod-nil-grace-period", false /* criticalPod */, nil /* terminationGracePeriod */)
criticalPodNoGracePeriod := makePod("critical-pod-nil-grace-period", true /* criticalPod */, nil /* terminationGracePeriod */)
@ -305,3 +309,52 @@ func TestFeatureEnabled(t *testing.T) {
})
}
}
func TestRestart(t *testing.T) {
systemDbusTmp := systemDbus
defer func() {
systemDbus = systemDbusTmp
}()
shutdownGracePeriodRequested := 30 * time.Second
shutdownGracePeriodCriticalPods := 10 * time.Second
systemInhibitDelay := 40 * time.Second
overrideSystemInhibitDelay := 40 * time.Second
activePodsFunc := func() []*v1.Pod {
return nil
}
killPodsFunc := func(pod *v1.Pod, status v1.PodStatus, gracePeriodOverride *int64) error {
return nil
}
syncNodeStatus := func() {}
var shutdownChan chan bool
var connChan = make(chan struct{}, 1)
systemDbus = func() (dbusInhibiter, error) {
defer func() {
connChan <- struct{}{}
}()
shutdownChan = make(chan bool)
dbus := &fakeDbus{currentInhibitDelay: systemInhibitDelay, shutdownChan: shutdownChan, overrideSystemInhibitDelay: overrideSystemInhibitDelay}
return dbus, nil
}
manager, _ := NewManager(activePodsFunc, killPodsFunc, syncNodeStatus, shutdownGracePeriodRequested, shutdownGracePeriodCriticalPods)
err := manager.Start()
if err != nil {
t.Errorf("unexpected error: %v", err)
}
for i := 0; i != 5; i++ {
select {
case <-time.After(dbusReconnectPeriod * 5):
t.Fatal("wait dbus connect timeout")
case <-connChan:
}
time.Sleep(time.Second)
close(shutdownChan)
}
}

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@ -47,6 +47,17 @@ type DBusCon struct {
SystemBus dBusConnector
}
func NewDBusCon() (*DBusCon, error) {
conn, err := dbus.SystemBus()
if err != nil {
return nil, err
}
return &DBusCon{
SystemBus: conn,
}, nil
}
// InhibitLock is a lock obtained after creating an systemd inhibitor by calling InhibitShutdown().
type InhibitLock uint32
@ -138,7 +149,11 @@ func (bus *DBusCon) MonitorShutdown() (<-chan bool, error) {
go func() {
for {
event := <-busChan
event, ok := <-busChan
if !ok {
close(shutdownChan)
return
}
if event == nil || len(event.Body) == 0 {
klog.ErrorS(nil, "Failed obtaining shutdown event, PrepareForShutdown event was empty")
continue
@ -149,7 +164,6 @@ func (bus *DBusCon) MonitorShutdown() (<-chan bool, error) {
continue
}
shutdownChan <- shutdownActive
}
}()

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@ -178,6 +178,24 @@ var _ = SIGDescribe("GracefulNodeShutdown [Serial] [NodeAlphaFeature:GracefulNod
return nil
}, nodeStatusUpdateTimeout, pollInterval).Should(gomega.BeNil())
})
ginkgo.It("after restart dbus, should be able to gracefully shutdown", func() {
ginkgo.By("Restart Dbus")
err := restartDbus()
framework.ExpectNoError(err)
ginkgo.By("Emitting Shutdown signal")
err = emitSignalPrepareForShutdown(true)
framework.ExpectNoError(err)
gomega.Eventually(func() error {
isReady := getNodeReadyStatus(f)
if isReady {
return fmt.Errorf("node did not become shutdown as expected")
}
return nil
}, nodeStatusUpdateTimeout, pollInterval).Should(gomega.BeNil())
})
})
})
@ -237,3 +255,9 @@ func getNodeReadyStatus(f *framework.Framework) bool {
framework.ExpectEqual(len(nodeList.Items), 1)
return isNodeReady(&nodeList.Items[0])
}
func restartDbus() error {
cmd := "systemctl restart dbus"
_, err := runCommand("sh", "-c", cmd)
return err
}