Force hyperthreading on masters/workers

TODO: filter out RHCOS systems
openshift · Oct 23, 2019 · 30f7af9 · 30f7af9
1 parent 2827ba5
commit 30f7af9
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Showing 3 changed files with 33 additions and 0 deletions.
diff --git a/pkg/asset/machines/machineconfig/hyperthreading.go b/pkg/asset/machines/machineconfig/hyperthreading.go
@@ -38,3 +38,32 @@ func ForHyperthreadingDisabled(role string) *mcfgv1.MachineConfig {
 		},
 	}
 }
+
+// ForceHyperthreadingEnabled creates the MachineConfig to force enabled hyperthreading.
+// FCOS ships with "mitigations=auto,nosmt" karg, which needs to be disabled to avoid bumping up instance sizes
+func ForceHyperthreadingEnabled(role string) *mcfgv1.MachineConfig {
+	return &mcfgv1.MachineConfig{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "machineconfiguration.openshift.io/v1",
+			Kind:       "MachineConfig",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Name: fmt.Sprintf("99-%s-force-enabled-hyperthreading", role),
+			Labels: map[string]string{
+				"machineconfiguration.openshift.io/role": role,
+			},
+		},
+		Spec: mcfgv1.MachineConfigSpec{
+			Config: igntypes.Config{
+				Ignition: igntypes.Ignition{
+					Version: igntypes.MaxVersion.String(),
+				},
+				Storage: igntypes.Storage{
+					Files: []igntypes.File{
+						ignition.FileFromString("/etc/pivot/kernel-args", "root", 0600, "DELETE mitigations=auto,nosmt"),
+					},
+				},
+			},
+		},
+	}
+}
diff --git a/pkg/asset/machines/master.go b/pkg/asset/machines/master.go
@@ -281,6 +281,8 @@ func (m *Master) Generate(dependencies asset.Parents) error {
 	machineConfigs := []*mcfgv1.MachineConfig{}
 	if pool.Hyperthreading == types.HyperthreadingDisabled {
 		machineConfigs = append(machineConfigs, machineconfig.ForHyperthreadingDisabled("master"))
+	} else {
+		machineConfigs = append(machineConfigs, machineconfig.ForceHyperthreadingEnabled("master"))
 	}
 	if ic.SSHKey != "" {
 		machineConfigs = append(machineConfigs, machineconfig.ForAuthorizedKeys(ic.SSHKey, "master"))

diff --git a/pkg/asset/machines/worker.go b/pkg/asset/machines/worker.go
@@ -137,6 +137,8 @@ func (w *Worker) Generate(dependencies asset.Parents) error {
 	for _, pool := range ic.Compute {
 		if pool.Hyperthreading == types.HyperthreadingDisabled {
 			machineConfigs = append(machineConfigs, machineconfig.ForHyperthreadingDisabled("worker"))
+		} else {
+			machineConfigs = append(machineConfigs, machineconfig.ForceHyperthreadingEnabled("worker"))
 		}
 		if ic.SSHKey != "" {
 			machineConfigs = append(machineConfigs, machineconfig.ForAuthorizedKeys(ic.SSHKey, "worker"))