diff --git a/Makefile b/Makefile
index 4c9617560..48505c188 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-VERSION := 0.5.1
+VERSION := 0.5.2
 
 # Name of this service/application
 SERVICE_NAME := redis-operator
diff --git a/api/redisfailover/v1alpha2/defaults.go b/api/redisfailover/v1alpha2/defaults.go
new file mode 100644
index 000000000..5ca24aee5
--- /dev/null
+++ b/api/redisfailover/v1alpha2/defaults.go
@@ -0,0 +1,14 @@
+package v1alpha2
+
+const (
+	defaultRedisNumber          = 3
+	defaultSentinelNumber       = 3
+	defaultExporterImage        = "oliver006/redis_exporter"
+	defaultExporterImageVersion = "v0.11.3"
+	defaultRedisImage           = "redis"
+	defaultRedisImageVersion    = "3.2-alpine"
+)
+
+var (
+	defaultSentinelCustomConfig = []string{"down-after-milliseconds 5000", "failover-timeout 10000"}
+)
diff --git a/api/redisfailover/v1alpha2/validate.go b/api/redisfailover/v1alpha2/validate.go
new file mode 100644
index 000000000..3d073aa2b
--- /dev/null
+++ b/api/redisfailover/v1alpha2/validate.go
@@ -0,0 +1,42 @@
+package v1alpha2
+
+import (
+	"errors"
+)
+
+// Validate set the values by default if not defined and checks if the values given are valid
+func (r *RedisFailover) Validate() error {
+	if r.Spec.Redis.Replicas == 0 {
+		r.Spec.Redis.Replicas = defaultRedisNumber
+	} else if r.Spec.Redis.Replicas < defaultRedisNumber {
+		return errors.New("number of redises in spec is less than the minimum")
+	}
+
+	if r.Spec.Sentinel.Replicas == 0 {
+		r.Spec.Sentinel.Replicas = defaultSentinelNumber
+	} else if r.Spec.Sentinel.Replicas < defaultSentinelNumber {
+		return errors.New("number of sentinels in spec is less than the minimum")
+	}
+
+	if r.Spec.Redis.Image == "" {
+		r.Spec.Redis.Image = defaultRedisImage
+	}
+
+	if r.Spec.Redis.Version == "" {
+		r.Spec.Redis.Version = defaultRedisImageVersion
+	}
+
+	if r.Spec.Redis.ExporterImage == "" {
+		r.Spec.Redis.ExporterImage = defaultExporterImage
+	}
+
+	if r.Spec.Redis.ExporterVersion == "" {
+		r.Spec.Redis.ExporterVersion = defaultExporterImageVersion
+	}
+
+	if len(r.Spec.Sentinel.CustomConfig) == 0 {
+		r.Spec.Sentinel.CustomConfig = defaultSentinelCustomConfig
+	}
+
+	return nil
+}
diff --git a/operator/redisfailover/handler.go b/operator/redisfailover/handler.go
index c4ce02b73..57bb06367 100644
--- a/operator/redisfailover/handler.go
+++ b/operator/redisfailover/handler.go
@@ -62,6 +62,10 @@ func (r *RedisFailoverHandler) Add(_ context.Context, obj runtime.Object) error
 		return fmt.Errorf("can't handle redis failover state, parentLabels map[string]string, ownerRefs []metav1.OwnerReferencenot a redisfailover object")
 	}
 
+	if err := rf.Validate(); err != nil {
+		return err
+	}
+
 	// Create owner refs so the objects manager by this handler have ownership to the
 	// received RF.
 	oRefs := r.createOwnerReferences(rf)
diff --git a/operator/redisfailover/service/constants.go b/operator/redisfailover/service/constants.go
index 079adf75d..1ce7f320a 100644
--- a/operator/redisfailover/service/constants.go
+++ b/operator/redisfailover/service/constants.go
@@ -5,17 +5,6 @@ const (
 	logNamespaceField = "namespace"
 )
 
-const (
-	// ExporterImage defines the redis exporter image
-	ExporterImage = "oliver006/redis_exporter"
-	// ExporterImageVersion defines the redis exporter version
-	ExporterImageVersion = "v0.11.3"
-	// RedisImage defines the redis image
-	RedisImage = "redis"
-	// RedisImageVersion defines the redis image version
-	RedisImageVersion = "3.2-alpine"
-)
-
 // variables refering to the redis exporter port
 const (
 	exporterPort                 = 9121
diff --git a/operator/redisfailover/service/generator.go b/operator/redisfailover/service/generator.go
index fb86b9611..e95e370a3 100644
--- a/operator/redisfailover/service/generator.go
+++ b/operator/redisfailover/service/generator.go
@@ -18,6 +18,8 @@ const (
 	redisConfigurationVolumeName         = "redis-config"
 	redisShutdownConfigurationVolumeName = "redis-shutdown-config"
 	redisStorageVolumeName               = "redis-data"
+
+	graceTime = 60
 )
 
 func generateSentinelService(rf *redisfailoverv1alpha2.RedisFailover, labels map[string]string, ownerRefs []metav1.OwnerReference) *corev1.Service {
@@ -202,7 +204,7 @@ func generateRedisStatefulSet(rf *redisfailoverv1alpha2.RedisFailover, labels ma
 								fmt.Sprintf("/redis/%s", redisConfigFileName),
 							},
 							ReadinessProbe: &corev1.Probe{
-								InitialDelaySeconds: 15,
+								InitialDelaySeconds: graceTime,
 								TimeoutSeconds:      5,
 								Handler: corev1.Handler{
 									Exec: &corev1.ExecAction{
@@ -215,7 +217,7 @@ func generateRedisStatefulSet(rf *redisfailoverv1alpha2.RedisFailover, labels ma
 								},
 							},
 							LivenessProbe: &corev1.Probe{
-								InitialDelaySeconds: 5,
+								InitialDelaySeconds: graceTime,
 								TimeoutSeconds:      5,
 								Handler: corev1.Handler{
 									Exec: &corev1.ExecAction{
@@ -348,7 +350,7 @@ func generateSentinelDeployment(rf *redisfailoverv1alpha2.RedisFailover, labels
 								"--sentinel",
 							},
 							ReadinessProbe: &corev1.Probe{
-								InitialDelaySeconds: 15,
+								InitialDelaySeconds: graceTime,
 								TimeoutSeconds:      5,
 								Handler: corev1.Handler{
 									Exec: &corev1.ExecAction{
@@ -361,7 +363,7 @@ func generateSentinelDeployment(rf *redisfailoverv1alpha2.RedisFailover, labels
 								},
 							},
 							LivenessProbe: &corev1.Probe{
-								InitialDelaySeconds: 5,
+								InitialDelaySeconds: graceTime,
 								TimeoutSeconds:      5,
 								Handler: corev1.Handler{
 									Exec: &corev1.ExecAction{
@@ -541,31 +543,11 @@ func getQuorum(rf *redisfailoverv1alpha2.RedisFailover) int32 {
 }
 
 func getRedisImage(rf *redisfailoverv1alpha2.RedisFailover) string {
-	image := RedisImage
-	if rf.Spec.Redis.Image != "" {
-		image = rf.Spec.Redis.Image
-	}
-
-	version := RedisImageVersion
-	if rf.Spec.Redis.Version != "" {
-		version = rf.Spec.Redis.Version
-	}
-
-	return fmt.Sprintf("%s:%s", image, version)
+	return fmt.Sprintf("%s:%s", rf.Spec.Redis.Image, rf.Spec.Redis.Version)
 }
 
 func getRedisExporterImage(rf *redisfailoverv1alpha2.RedisFailover) string {
-	image := ExporterImage
-	if rf.Spec.Redis.ExporterImage != "" {
-		image = rf.Spec.Redis.ExporterImage
-	}
-
-	version := ExporterImageVersion
-	if rf.Spec.Redis.ExporterVersion != "" {
-		version = rf.Spec.Redis.ExporterVersion
-	}
-
-	return fmt.Sprintf("%s:%s", image, version)
+	return fmt.Sprintf("%s:%s", rf.Spec.Redis.ExporterImage, rf.Spec.Redis.ExporterVersion)
 }
 
 func getRedisVolumeMounts(rf *redisfailoverv1alpha2.RedisFailover) []corev1.VolumeMount {
diff --git a/operator/redisfailover/service/heal.go b/operator/redisfailover/service/heal.go
index 41d250bbb..b4d54794c 100644
--- a/operator/redisfailover/service/heal.go
+++ b/operator/redisfailover/service/heal.go
@@ -1,6 +1,7 @@
 package service
 
 import (
+	"errors"
 	"strconv"
 
 	redisfailoverv1alpha2 "github.com/spotahome/redis-operator/api/redisfailover/v1alpha2"
@@ -41,6 +42,9 @@ func (r *RedisFailoverHealer) SetRandomMaster(rf *redisfailoverv1alpha2.RedisFai
 	if err != nil {
 		return err
 	}
+	if len(ssp.Items) < 1 {
+		return errors.New("number of redis pods are 0")
+	}
 	newMasterIP := ""
 	for _, pod := range ssp.Items {
 		if newMasterIP == "" {