Periodically updates machine info

docs/runtime_options.md

@@ -107,6 +107,7 @@ cAdvisor stores the latest historical data in memory. How long of a history it s
 ```
 --boot_id_file="/proc/sys/kernel/random/boot_id": Comma-separated list of files to check for boot-id. Use the first one that exists. (default "/proc/sys/kernel/random/boot_id")
 --machine_id_file="/etc/machine-id,/var/lib/dbus/machine-id": Comma-separated list of files to check for machine-id. Use the first one that exists. (default "/etc/machine-id,/var/lib/dbus/machine-id")
+--update_machine_info_interval=5m: Interval between machine info updates. (default 5m)
 ```
 
 ## Metrics

manager/manager.go

@@ -56,6 +56,7 @@ import (
 )
 
 var globalHousekeepingInterval = flag.Duration("global_housekeeping_interval", 1*time.Minute, "Interval between global housekeepings")
+var updateMachineInfoInterval = flag.Duration("update_machine_info_interval", 5*time.Minute, "Interval between machine info updates.")
 var logCadvisorUsage = flag.Bool("log_cadvisor_usage", false, "Whether to log the usage of the cAdvisor container")
 var eventStorageAgeLimit = flag.String("event_storage_age_limit", "default=24h", "Max length of time for which to store events (per type). Value is a comma separated list of key values, where the keys are event types (e.g.: creation, oom) or \"default\" and the value is a duration. Default is applied to all non-specified event types")
 var eventStorageEventLimit = flag.String("event_storage_event_limit", "default=100000", "Max number of events to store (per type). Value is a comma separated list of key values, where the keys are event types (e.g.: creation, oom) or \"default\" and the value is an integer. Default is applied to all non-specified event types")
@@ -208,6 +209,7 @@ func New(memoryCache *memory.InMemoryCache, sysfs sysfs.SysFs, maxHousekeepingIn
 		quitChannels:                          make([]chan error, 0, 2),
 		memoryCache:                           memoryCache,
 		fsInfo:                                fsInfo,
+		sysFs:                                 sysfs,
 		cadvisorContainer:                     selfContainer,
 		inHostNamespace:                       inHostNamespace,
 		startupTime:                           time.Now(),
@@ -277,6 +279,8 @@ type manager struct {
 	containersLock           sync.RWMutex
 	memoryCache              *memory.InMemoryCache
 	fsInfo                   fs.FsInfo
+	sysFs                    sysfs.SysFs
+	machineMu                sync.RWMutex // protects machineInfo
 	machineInfo              info.MachineInfo
 	quitChannels             []chan error
 	cadvisorContainer        string
@@ -382,6 +386,10 @@ func (self *manager) Start() error {
 	self.quitChannels = append(self.quitChannels, quitGlobalHousekeeping)
 	go self.globalHousekeeping(quitGlobalHousekeeping)
 
+	quitUpdateMachineInfo := make(chan error)
+	self.quitChannels = append(self.quitChannels, quitUpdateMachineInfo)
+	go self.updateMachineInfo(quitUpdateMachineInfo)
+
 	return nil
 }
 
@@ -402,6 +410,28 @@ func (self *manager) Stop() error {
 	return nil
 }
 
+func (self *manager) updateMachineInfo(quit chan error) {
+	ticker := time.NewTicker(*updateMachineInfoInterval)
+	for {
+		select {
+		case <-ticker.C:
+			info, err := machine.Info(self.sysFs, self.fsInfo, self.inHostNamespace)
+			if err != nil {
+				klog.Errorf("Could not get machine info: %v", err)
+				break
+			}
+			self.machineMu.Lock()
+			self.machineInfo = *info
+			self.machineMu.Unlock()
+			klog.V(5).Infof("Update machine info: %+v", *info)
+		case <-quit:
+			ticker.Stop()
+			quit <- nil
+			return
+		}
+	}
+}
+
 func (self *manager) globalHousekeeping(quit chan error) {
 	// Long housekeeping is either 100ms or half of the housekeeping interval.
 	longHousekeeping := 100 * time.Millisecond
@@ -501,7 +531,9 @@ func (self *manager) getAdjustedSpec(cinfo *containerInfo) info.ContainerSpec {
 	if spec.HasMemory {
 		// Memory.Limit is 0 means there's no limit
 		if spec.Memory.Limit == 0 {
+			self.machineMu.RLock()
 			spec.Memory.Limit = uint64(self.machineInfo.MemoryCapacity)
+			self.machineMu.RUnlock()
 		}
 	}
 	return spec
@@ -834,6 +866,8 @@ func (self *manager) GetFsInfo(label string) ([]v2.FsInfo, error) {
 }
 
 func (m *manager) GetMachineInfo() (*info.MachineInfo, error) {
+	m.machineMu.RLock()
+	defer m.machineMu.RUnlock()
 	// Copy and return the MachineInfo.
 	return &m.machineInfo, nil
 }