From c5c0cfd74e902cd9757ad7a804deaa36359ada68 Mon Sep 17 00:00:00 2001
From: Andrew Beekhof <andrew@beekhof.net>
Date: Wed, 28 Aug 2019 10:06:32 +1000
Subject: [PATCH] Use 'Replica: 1' on clusters with a single master

---
 .../machineremediation/v1alpha1/BUILD.bazel   |  2 ++
 .../machineremediation/v1alpha1/replicas.go   | 35 +++++++++++++++++++
 pkg/operator/operator_test.go                 |  4 +--
 pkg/operator/resources.go                     |  2 +-
 4 files changed, 40 insertions(+), 3 deletions(-)
 create mode 100644 pkg/apis/machineremediation/v1alpha1/replicas.go

diff --git a/pkg/apis/machineremediation/v1alpha1/BUILD.bazel b/pkg/apis/machineremediation/v1alpha1/BUILD.bazel
index bbac7197..71397451 100644
--- a/pkg/apis/machineremediation/v1alpha1/BUILD.bazel
+++ b/pkg/apis/machineremediation/v1alpha1/BUILD.bazel
@@ -9,6 +9,7 @@ go_library(
         "machineremediation_types.go",
         "machineremediationoperator_types.go",
         "register.go",
+        "replicas.go",
         "zz_generated.deepcopy.go",
     ],
     importpath = "kubevirt.io/machine-remediation-operator/pkg/apis/machineremediation/v1alpha1",
@@ -19,5 +20,6 @@ go_library(
         "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
+        "//vendor/sigs.k8s.io/controller-runtime/pkg/client:go_default_library",
     ],
 )
diff --git a/pkg/apis/machineremediation/v1alpha1/replicas.go b/pkg/apis/machineremediation/v1alpha1/replicas.go
new file mode 100644
index 00000000..87a30f12
--- /dev/null
+++ b/pkg/apis/machineremediation/v1alpha1/replicas.go
@@ -0,0 +1,35 @@
+// NOTE: Boilerplate only.  Ignore this file.
+
+// Package v1alpha1 contains API Schema definitions for the healthchecking v1alpha1 API group
+// +k8s:deepcopy-gen=package,register
+// +groupName=machineremediation.kubevirt.io
+package v1alpha1
+
+import (
+	"context"
+	corev1 "k8s.io/api/core/v1"
+        "sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+const (
+        NamespaceOpenShiftMachineAPI = "openshift-machine-api"
+        MasterNodeRoleLabel = "node-role.kubernetes.io/master"
+)
+
+func GetReplicaCount(c client.Client) int32 { 
+        masterNodes := &corev1.NodeList{} 
+        err := c.List( 
+                context.TODO(), 
+                masterNodes, 
+                client.InNamespace(NamespaceOpenShiftMachineAPI), 
+                client.MatchingLabels(map[string]string{MasterNodeRoleLabel: ""}), 
+        ) 
+        if err != nil { 
+                return 1
+        } 
+        if len(masterNodes.Items) < 2 { 
+                return 1
+        } 
+        return 2
+} 
+
diff --git a/pkg/operator/operator_test.go b/pkg/operator/operator_test.go
index 81b75476..79e994fb 100644
--- a/pkg/operator/operator_test.go
+++ b/pkg/operator/operator_test.go
@@ -138,8 +138,8 @@ func TestReconcile(t *testing.T) {
 
 	// update all deployments status to have desired number of replicas
 	for _, d := range deploys.Items {
-		d.Status.Replicas = 2
-		d.Status.UpdatedReplicas = 2
+		d.Status.Replicas = mrv1.GetReplicaCount(r.client)
+		d.Status.UpdatedReplicas = mrv1.GetReplicaCount(r.client)
 		assert.NoError(t, r.client.Update(context.TODO(), &d))
 	}
 
diff --git a/pkg/operator/resources.go b/pkg/operator/resources.go
index 670af050..326f2747 100644
--- a/pkg/operator/resources.go
+++ b/pkg/operator/resources.go
@@ -48,7 +48,7 @@ func (r *ReconcileMachineRemediationOperator) createOrUpdateDeployment(data *com
 	}
 
 	newDeploy := components.NewDeployment(data)
-	newDeploy.Spec.Replicas = pointer.Int32Ptr(2)
+	newDeploy.Spec.Replicas = pointer.Int32Ptr(mrv1.GetReplicaCount(r.client))
 
 	oldDeploy, err := r.getDeployment(data.Name, data.Namespace)
 	if errors.IsNotFound(err) {