feat(cloudprovider): add IBM disruption reasons

Signed-off-by: Anand Nekkunti <anand.nekkunti@ibm.com>

Author: nekkunti

pkg/cloudprovider/cloudprovider.go

@@ -47,6 +47,26 @@ import (
 
 const CloudProviderName = "ibmcloud"
 
+// Disruption reasons specific to the IBM Cloud provider.
+// They are used to surface why nodes were disrupted (drift, quota issues, etc)
+// through Karpenter's disruption events and metrics.
+const (
+	// DisruptionReasonVPCQuotaExceeded indicates the VPC/Network quota was exceeded
+	// (for example, no more IP addresses available or VPC resource quota reached)
+	// which prevented provisioning or caused instance failures.
+	DisruptionReasonVPCQuotaExceeded karpv1.DisruptionReason = "VPCQuotaExceeded"
+
+	// DisruptionReasonAPIRateLimited indicates disruption due to IBM Cloud
+	// API rate limiting (throttling), where provisioning/sync operations
+	// repeatedly failed with rate-limit errors.
+	DisruptionReasonAPIRateLimited karpv1.DisruptionReason = "APIRateLimited"
+
+	// DisruptionReasonInstanceTerminated indicates the instance was terminated
+	// (e.g., by user action, by cloud provider lifecycle, or due to an underlying
+	// platform event).
+	DisruptionReasonInstanceTerminated karpv1.DisruptionReason = "InstanceTerminated"
+)
+
 var _ cloudprovider.CloudProvider = (*CloudProvider)(nil)
 
 type CloudProvider struct {
@@ -651,3 +671,12 @@ func (c *CloudProvider) RepairPolicies() []cloudprovider.RepairPolicy {
 		},
 	}
 }
+
+// DisruptionReasons returns the IBM Cloud provider disruption reasons.
+func (c *CloudProvider) DisruptionReasons() []karpv1.DisruptionReason {
+	return []karpv1.DisruptionReason{
+		DisruptionReasonVPCQuotaExceeded,
+		DisruptionReasonAPIRateLimited,
+		DisruptionReasonInstanceTerminated,
+	}
+}

pkg/cloudprovider/cloudprovider_test.go

@@ -1123,3 +1123,21 @@ func TestCloudProvider_List(t *testing.T) {
 		})
 	}
 }
+
+func TestDisruptionReasonConstants(t *testing.T) {
+	assert.Equal(t, karpv1.DisruptionReason("VPCQuotaExceeded"), DisruptionReasonVPCQuotaExceeded)
+	assert.Equal(t, karpv1.DisruptionReason("APIRateLimited"), DisruptionReasonAPIRateLimited)
+	assert.Equal(t, karpv1.DisruptionReason("InstanceTerminated"), DisruptionReasonInstanceTerminated)
+}
+
+func TestDisruptionReasons(t *testing.T) {
+	cp := &CloudProvider{}
+	expected := []karpv1.DisruptionReason{
+		DisruptionReasonVPCQuotaExceeded,
+		DisruptionReasonAPIRateLimited,
+		DisruptionReasonInstanceTerminated,
+	}
+	got := cp.DisruptionReasons()
+	assert.ElementsMatch(t, expected, got)
+
+}