CLOUDP-58090: Create StatefulSet that starts agent image (#12)

Author: chatton

cmd/manager/main.go

@@ -6,7 +6,6 @@ import (
 	"github.com/mongodb/mongodb-kubernetes-operator/pkg/controller"
 	"go.uber.org/zap"
 	"os"
-
 	"sigs.k8s.io/controller-runtime/pkg/client/config"
 	"sigs.k8s.io/controller-runtime/pkg/manager"
 	"sigs.k8s.io/controller-runtime/pkg/manager/signals"
@@ -31,6 +30,13 @@ func main() {
 	if err != nil {
 		os.Exit(1)
 	}
+
+	// TODO: implement mechanism to specify required/optional environment variables
+	if _, agentImageSpecified := os.LookupEnv("AGENT_IMAGE"); !agentImageSpecified {
+		log.Error("required environment variable AGENT_IMAGE not found")
+		os.Exit(1)
+	}
+
 	// get watch namespace from environment variable
 	namespace, nsSpecified := os.LookupEnv("WATCH_NAMESPACE")
 	if !nsSpecified {
@@ -49,7 +55,7 @@ func main() {
 	mgr, err := manager.New(cfg, manager.Options{
 		Namespace: namespace,
 	})
-	
+
 	if err != nil {
 		os.Exit(1)
 	}

deploy/crds/mongodb.com_v1_mongodb_cr.yaml

@@ -4,5 +4,5 @@ metadata:
   name: example-mongodb
 spec:
   members: 3
-  kind: ReplicaSet
+  type: ReplicaSet
   version: "4.0.6"

deploy/operator.yaml

@@ -31,3 +31,5 @@ spec:
                   fieldPath: metadata.name
             - name: OPERATOR_NAME
               value: "mongodb-kubernetes-operator"
+            - name: AGENT_IMAGE # The MongoDB Agent the operator will deploy to manage MongoDB deployments
+              value: REPLACE_IMAGE

pkg/controller/mongodb/mongodb_controller.go

@@ -4,12 +4,16 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"os"
+
 	mdbv1 "github.com/mongodb/mongodb-kubernetes-operator/pkg/apis/mongodb/v1"
 	"github.com/mongodb/mongodb-kubernetes-operator/pkg/automationconfig"
 	mdbClient "github.com/mongodb/mongodb-kubernetes-operator/pkg/kube/client"
 	"github.com/mongodb/mongodb-kubernetes-operator/pkg/kube/configmap"
+	"github.com/mongodb/mongodb-kubernetes-operator/pkg/kube/resourcerequirements"
 	"github.com/mongodb/mongodb-kubernetes-operator/pkg/kube/statefulset"
 	"go.uber.org/zap"
+	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -22,7 +26,9 @@ import (
 )
 
 const (
-	automationConfigKey = "automation-config"
+	automationConfigKey   = "automation-config"
+	agentName             = "mongodb-agent"
+	agentImageEnvVariable = "AGENT_IMAGE"
 )
 
 // Add creates a new MongoDB Controller and adds it to the Manager. The Manager will set fields on the Controller
@@ -92,32 +98,20 @@ func (r *ReplicaSetReconciler) Reconcile(request reconcile.Request) (reconcile.R
 	// TODO: Read current automation config version from config map
 
 	if err := r.ensureAutomationConfig(mdb); err != nil {
-		log.Errorf("failed creating config map: %s", err)
+		log.Warnf("failed creating config map: %s", err)
 		return reconcile.Result{}, err
 	}
 
 	// TODO: Create the service for the MDB resource
 
-	labels := map[string]string{
-		"dummy": "label",
+	sts, err := buildStatefulSet(mdb)
+	if err != nil {
+		log.Warnf("error building StatefulSet: %s", err)
+		return reconcile.Result{}, nil
 	}
 
-	sts, err := statefulset.NewBuilder().
-		SetPodTemplateSpec(corev1.PodTemplateSpec{
-			ObjectMeta: metav1.ObjectMeta{
-				Labels: labels,
-			},
-			Spec: corev1.PodSpec{},
-		}).
-		SetNamespace(request.NamespacedName.Namespace).
-		SetName(request.NamespacedName.Name).
-		SetReplicas(mdb.Spec.Members).
-		SetLabels(labels).
-		SetMatchLabels(labels).
-		Build()
-
 	if err = r.client.CreateOrUpdate(&sts); err != nil {
-		log.Errorf("error creating/updating StatefulSet: %s", err)
+		log.Warnf("error creating/updating StatefulSet: %s", err)
 		return reconcile.Result{}, err
 	}
 
@@ -162,6 +156,40 @@ func buildAutomationConfigConfigMap(mdb mdbv1.MongoDB) (corev1.ConfigMap, error)
 		Build(), nil
 }
 
+// buildStatefulSet takes a MongoDB resource and converts it into
+// the corresponding stateful set
+func buildStatefulSet(mdb mdbv1.MongoDB) (appsv1.StatefulSet, error) {
+	labels := map[string]string{
+		"dummy": "label",
+	}
+	agentContainer := corev1.Container{
+		Name:      agentName,
+		Image:     os.Getenv(agentImageEnvVariable),
+		Resources: resourcerequirements.Defaults(),
+		Command:   []string{"agent/mongodb-agent", "-cluster=/var/lib/automation/config/automation-config.json"},
+	}
+
+	podSpecTemplate := corev1.PodTemplateSpec{
+		ObjectMeta: metav1.ObjectMeta{
+			Labels: labels,
+		},
+		Spec: corev1.PodSpec{
+			Containers: []corev1.Container{
+				agentContainer,
+			},
+		},
+	}
+
+	return statefulset.NewBuilder().
+		SetPodTemplateSpec(podSpecTemplate).
+		SetNamespace(mdb.Namespace).
+		SetName(mdb.Name).
+		SetReplicas(mdb.Spec.Members).
+		SetLabels(labels).
+		SetMatchLabels(labels).
+		Build()
+}
+
 func getDomain(service, namespace, clusterName string) string {
 	if clusterName == "" {
 		clusterName = "cluster.local"

pkg/controller/mongodb/replicaset_controller_test.go

@@ -2,26 +2,39 @@ package mongodb
 
 import (
 	"context"
+	"os"
+	"testing"
+
 	mdbv1 "github.com/mongodb/mongodb-kubernetes-operator/pkg/apis/mongodb/v1"
 	"github.com/mongodb/mongodb-kubernetes-operator/pkg/kube/client"
+	"github.com/mongodb/mongodb-kubernetes-operator/pkg/kube/resourcerequirements"
 	"github.com/stretchr/testify/assert"
+	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
 	"sigs.k8s.io/controller-runtime/pkg/reconcile"
-	"testing"
 )
 
-func TestKubernetesResources_AreCreated(t *testing.T) {
-	// TODO: Create builder/yaml fixture of some type to construct MDB objects for unit tests
-	mdb := mdbv1.MongoDB{
+func init() {
+	os.Setenv("AGENT_IMAGE", "agent-image")
+}
+
+func newTestReplicaSet() mdbv1.MongoDB {
+	return mdbv1.MongoDB{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      "my-rs",
 			Namespace: "my-ns",
 		},
-		Spec:   mdbv1.MongoDBSpec{},
-		Status: mdbv1.MongoDBStatus{},
+		Spec: mdbv1.MongoDBSpec{
+			Members: 3,
+		},
 	}
+}
+
+func TestKubernetesResources_AreCreated(t *testing.T) {
+	// TODO: Create builder/yaml fixture of some type to construct MDB objects for unit tests
+	mdb := newTestReplicaSet()
 
 	mgr := client.NewManager(&mdb)
 	r := newReconciler(mgr)
@@ -37,3 +50,21 @@ func TestKubernetesResources_AreCreated(t *testing.T) {
 	assert.Contains(t, cm.Data, automationConfigKey)
 	assert.NotEmpty(t, cm.Data[automationConfigKey])
 }
+
+func TestStatefulSet_IsCorrectlyConfigured(t *testing.T) {
+	mdb := newTestReplicaSet()
+	mgr := client.NewManager(&mdb)
+	r := newReconciler(mgr)
+	res, err := r.Reconcile(reconcile.Request{NamespacedName: types.NamespacedName{Namespace: mdb.Namespace, Name: mdb.Name}})
+	assertReconciliationSuccessful(t, res, err)
+
+	sts := appsv1.StatefulSet{}
+	err = mgr.GetClient().Get(context.TODO(), types.NamespacedName{Name: mdb.Name, Namespace: mdb.Namespace}, &sts)
+	assert.NoError(t, err)
+
+	agentContainer := sts.Spec.Template.Spec.Containers[0]
+	assert.Equal(t, agentName, agentContainer.Name)
+	assert.Equal(t, os.Getenv(agentImageEnvVariable), agentContainer.Image)
+
+	assert.Equal(t, resourcerequirements.Defaults(), agentContainer.Resources)
+}

pkg/kube/resourcerequirements/resource_requirements.go

@@ -0,0 +1,55 @@
+package resourcerequirements
+
+import (
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/resource"
+)
+
+const (
+	resourceMemory = "memory"
+	resourceCpu    = "cpu"
+)
+
+// Defaults returns the default resource requirements for a container
+func Defaults() corev1.ResourceRequirements {
+	// we can safely ignore the error as we are passing all valid values
+	req, _ := newDefaultRequirements()
+	return req
+}
+
+func newDefaultRequirements() (corev1.ResourceRequirements, error) {
+	return newRequirements("1.0", "500M", "0.5", "400M")
+}
+
+// newRequirements returns a new corev1.ResourceRequirements with the specified arguments, and an error
+// which indicates if there was a problem parsing the input
+func newRequirements(limitsCpu, limitsMemory, requestsCpu, requestsMemory string) (corev1.ResourceRequirements, error) {
+	limits, err := buildResourceList(limitsCpu, limitsMemory)
+	if err != nil {
+		return corev1.ResourceRequirements{}, err
+	}
+
+	requests, err := buildResourceList(requestsCpu, requestsMemory)
+	if err != nil {
+		return corev1.ResourceRequirements{}, err
+	}
+	return corev1.ResourceRequirements{
+		Limits:   limits,
+		Requests: requests,
+	}, nil
+}
+
+func buildResourceList(cpu, memory string) (corev1.ResourceList, error) {
+	cpuQuantity, err := resource.ParseQuantity(cpu)
+	if err != nil {
+		return nil, err
+	}
+	memoryQuantity, err := resource.ParseQuantity(memory)
+	if err != nil {
+		return nil, err
+	}
+	return corev1.ResourceList{
+		resourceCpu:    cpuQuantity,
+		resourceMemory: memoryQuantity,
+	}, nil
+}

pkg/kube/resourcerequirements/resource_requirements_test.go

@@ -0,0 +1,27 @@
+package resourcerequirements
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"k8s.io/apimachinery/pkg/api/resource"
+)
+
+func TestNewResourceRequirements_GetsConstructedCorrectly(t *testing.T) {
+	requirements, err := newRequirements("0.5", "2.0", "500", "1000")
+	assert.NoError(t, err)
+	assert.Equal(t, resource.MustParse("0.5"), *requirements.Limits.Cpu())
+	assert.Equal(t, resource.MustParse("2.0"), *requirements.Limits.Memory())
+	assert.Equal(t, resource.MustParse("500"), *requirements.Requests.Cpu())
+	assert.Equal(t, resource.MustParse("1000"), *requirements.Requests.Memory())
+}
+
+func TestBadInput_ReturnsError(t *testing.T) {
+	_, err := newRequirements("BAD_INPUT", "2.0", "500", "1000")
+	assert.Error(t, err)
+}
+
+func TestDefaultValues_DontReturnError(t *testing.T) {
+	_, err := newDefaultRequirements()
+	assert.NoError(t, err, "default requirements should never result in an error")
+}