keep stable order of agent pool profiles when reconciling managed cluster

Author: nojnhuh

azure/services/managedclusters/spec.go

@@ -21,6 +21,7 @@ import (
 	"encoding/base64"
 	"fmt"
 	"net"
+	"sort"
 
 	asocontainerservicev1 "github.com/Azure/azure-service-operator/v2/api/containerservice/v1api20231001"
 	asocontainerservicev1hub "github.com/Azure/azure-service-operator/v2/api/containerservice/v1api20231001/storage"
@@ -715,6 +716,11 @@ func (s *ManagedClusterSpec) Parameters(ctx context.Context, existingObj genrunt
 		}
 	}
 
+	// keep a consistent order to prevent unnecessary updates
+	sort.Slice(prevAgentPoolProfiles, func(i, j int) bool {
+		return ptr.Deref(prevAgentPoolProfiles[i].Name, "") < ptr.Deref(prevAgentPoolProfiles[j].Name, "")
+	})
+
 	managedCluster.Spec.AgentPoolProfiles = prevAgentPoolProfiles
 
 	if s.Preview {

azure/services/managedclusters/spec_test.go

@@ -57,9 +57,14 @@ func TestParameters(t *testing.T) {
 					&agentpools.AgentPoolSpec{
 						Replicas:  5,
 						Mode:      "mode",
-						AzureName: "agentpool",
+						AzureName: "agentpool-b",
 						Patches:   []string{`{"spec": {"tags": {"from": "patches"}}}`},
 					},
+					&agentpools.AgentPoolSpec{
+						Replicas:  10,
+						Mode:      "mode",
+						AzureName: "agentpool-a",
+					},
 				}, nil
 			},
 			PodCIDR:      "pod cidr",
@@ -140,11 +145,19 @@ func TestParameters(t *testing.T) {
 					},
 				},
 				AgentPoolProfiles: []asocontainerservicev1.ManagedClusterAgentPoolProfile{
+					{
+						Count:             ptr.To(10),
+						EnableAutoScaling: ptr.To(false),
+						Mode:              ptr.To(asocontainerservicev1.AgentPoolMode("mode")),
+						Name:              ptr.To("agentpool-a"),
+						OsDiskSizeGB:      ptr.To(asocontainerservicev1.ContainerServiceOSDisk(0)),
+						Type:              ptr.To(asocontainerservicev1.AgentPoolType_VirtualMachineScaleSets),
+					},
 					{
 						Count:             ptr.To(5),
 						EnableAutoScaling: ptr.To(false),
 						Mode:              ptr.To(asocontainerservicev1.AgentPoolMode("mode")),
-						Name:              ptr.To("agentpool"),
+						Name:              ptr.To("agentpool-b"),
 						OsDiskSizeGB:      ptr.To(asocontainerservicev1.ContainerServiceOSDisk(0)),
 						Type:              ptr.To(asocontainerservicev1.AgentPoolType_VirtualMachineScaleSets),
 						Tags:              map[string]string{"from": "patches"},