kubernetes/pkg/kubelet/util/boottime_util_linux.go

// GetBootTime returns the time at which the machine was started, truncated to the nearest second.
// It uses /proc/stat first, which is more accurate, and falls back to the less accurate
// unix.Sysinfo if /proc/stat failed.
func GetBootTime() (time.Time, error) { … }

func getBootTimeWithProcStat() (time.Time, error) { … }

func getBootTimeWithSysinfo() (time.Time, error) { … }