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machineconfig: Use nosmt KernelArgument now #4138

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cgwalters wants to merge 1 commit into from
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machineconfig: Use nosmt KernelArgument now #4138

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24 changes: 3 additions & 21 deletions pkg/asset/machines/machineconfig/hyperthreading.go
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Original file line number Diff line number Diff line change
Expand Up @@ -3,32 +3,13 @@ package machineconfig
import (
"fmt"

igntypes "github.com/coreos/ignition/v2/config/v3_1/types"
mcfgv1 "github.com/openshift/machine-config-operator/pkg/apis/machineconfiguration.openshift.io/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

"github.com/openshift/installer/pkg/asset/ignition"
)

// ForHyperthreadingDisabled creates the MachineConfig to disable hyperthreading.
// RHCOS ships with pivot.service that uses the `/etc/pivot/kernel-args` to override the kernel arguments for hosts.
// See https://github.com/openshift/machine-config-operator/blob/master/docs/MachineConfiguration.md#kernelarguments
func ForHyperthreadingDisabled(role string) (*mcfgv1.MachineConfig, error) {
ignConfig := igntypes.Config{
Ignition: igntypes.Ignition{
Version: igntypes.MaxVersion.String(),
},
Storage: igntypes.Storage{
Files: []igntypes.File{
ignition.FileFromString("/etc/pivot/kernel-args", "root", 0600, "ADD nosmt"),
},
},
}

rawExt, err := ignition.ConvertToRawExtension(ignConfig)
if err != nil {
return nil, err
}

return &mcfgv1.MachineConfig{
TypeMeta: metav1.TypeMeta{
APIVersion: "machineconfiguration.openshift.io/v1",
Expand All @@ -41,7 +22,8 @@ func ForHyperthreadingDisabled(role string) (*mcfgv1.MachineConfig, error) {
},
},
Spec: mcfgv1.MachineConfigSpec{
Config: rawExt,

@abhinavdahiya abhinavdahiya Sep 3, 2020

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https://github.com/openshift/machine-config-operator/blob/master/install/0000_80_machine-config-operator_01_machineconfig.crd.yaml#L70

That makes it feel like ignition field is required

@cgwalters cgwalters Sep 3, 2020

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Hmm possibly, I didn't test this locally; we also don't have CI coverage for this which probably needs to happen as a prerequisite. (It is IMO kind of a bug if the ignition section is really required becuase in exactly this case we're just using the "high level" MC section and not Ignition)

@LorbusChris LorbusChris Sep 16, 2020

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As of today, at least this has to be passed:

ignConfig := igntypes.Config{
    Ignition: igntypes.Ignition{
	Version: igntypes.MaxVersion.String(),
    },
}

// See https://access.redhat.com/solutions/rhel-smt
KernelArguments: []string{"nosmt"},
},
}, nil
}