pkg/types: set Azure machine pool defaults from defaultMachinePlatform

This commit updates default value handling when loading the
install config to set values in machine pools based on the
defaultMachinePlatform.

By populating the values directly in the install config, we can
avoid repetitive checks throughout the codebase to ensure the
default machine platform is applied to the relevant machine pool.

Author: patrickdillon

pkg/types/azure/defaults/platform.go

@@ -24,6 +24,17 @@ func SetPlatformDefaults(p *azure.Platform) {
 	}
 }
 
+// Apply sets values from the default machine platform to the machinepool.
+func Apply(defaultMachinePlatform, machinePool *azure.MachinePool) {
+	// Construct a temporary machine pool so we can set the
+	// defaults first, without overwriting the pool-sepcific values,
+	// which have precedence.
+	tempMP := &azure.MachinePool{}
+	tempMP.Set(defaultMachinePlatform)
+	tempMP.Set(machinePool)
+	machinePool.Set(tempMP)
+}
+
 // getInstanceClass returns the instance "class" we should use for a given region.
 func getInstanceClass(region string) string {
 	if class, ok := defaultMachineClass[region]; ok {

pkg/types/defaults/machinepools.go

@@ -2,6 +2,8 @@ package defaults
 
 import (
 	"github.com/openshift/installer/pkg/types"
+	"github.com/openshift/installer/pkg/types/azure"
+	azuredefaults "github.com/openshift/installer/pkg/types/azure/defaults"
 	"github.com/openshift/installer/pkg/types/gcp"
 	gcpdefaults "github.com/openshift/installer/pkg/types/gcp/defaults"
 	"github.com/openshift/installer/pkg/version"
@@ -24,6 +26,11 @@ func SetMachinePoolDefaults(p *types.MachinePool, platform *types.Platform) {
 	}
 
 	switch platform.Name() {
+	case azure.Name:
+		if p.Platform.Azure == nil && platform.Azure.DefaultMachinePlatform != nil {
+			p.Platform.Azure = &azure.MachinePool{}
+		}
+		azuredefaults.Apply(platform.Azure.DefaultMachinePlatform, p.Platform.Azure)
 	case gcp.Name:
 		gcpdefaults.SetMachinePoolDefaults(platform, p.Platform.GCP)
 	default: