// setupKernelTunables validates kernel tunable flags are set as expected
// depending upon the specified option, it will either warn, error, or modify the kernel tunable flags
func setupKernelTunables(option KernelTunableBehavior) error {
desiredState := map[string]int{
utilsysctl.VmOvercommitMemory: utilsysctl.VmOvercommitMemoryAlways,
utilsysctl.VmPanicOnOOM: utilsysctl.VmPanicOnOOMInvokeOOMKiller,
}
errList := []error{}
for flag, expectedValue := range desiredState {
val, err := utilsysctl.GetSysctl(flag)
if err != nil {
errList = append(errList, err)
continue
}
if val == expectedValue {
continue
}
switch option {
case KernelTunableError:
errList = append(errList, fmt.Errorf("Invalid kernel flag: %v, expected value: %v, actual value: %v", flag, expectedValue, val))
case KernelTunableWarn:
glog.V(2).Infof("Invalid kernel flag: %v, expected value: %v, actual value: %v", flag, expectedValue, val)
case KernelTunableModify:
glog.V(2).Infof("Updating kernel flag: %v, expected value: %v, actual value: %v", flag, expectedValue, val)
err = utilsysctl.SetSysctl(flag, expectedValue)
if err != nil {
errList = append(errList, err)
}
}
}
return errors.NewAggregate(errList)
}
// ShouldUseIptablesProxier returns true if we should use the iptables Proxier
// instead of the "classic" userspace Proxier. This is determined by checking
// the iptables version and for the existence of kernel features. It may return
// an error if it fails to get the itpables version without error, in which
// case it will also return false.
func ShouldUseIptablesProxier() (bool, error) {
exec := utilexec.New()
minVersion, err := semver.NewVersion(iptablesMinVersion)
if err != nil {
return false, err
}
// returns "X.X.X", err
versionString, err := utiliptables.GetIptablesVersionString(exec)
if err != nil {
return false, err
}
version, err := semver.NewVersion(versionString)
if err != nil {
return false, err
}
if version.LessThan(*minVersion) {
return false, nil
}
// Check for the required sysctls. We don't care about the value, just
// that it exists. If this Proxier is chosen, we'll iniialize it as we
// need.
_, err = utilsysctl.GetSysctl(sysctlRouteLocalnet)
if err != nil {
return false, err
}
return true, nil
}