add check if current master is affected

pkg/cluster/resources.go

@@ -2,6 +2,8 @@ package cluster
 
 import (
 	"fmt"
+	"strconv"
+	"strings"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
@@ -119,26 +121,54 @@ func (c *Cluster) createStatefulSet() (*v1beta1.StatefulSet, error) {
 	return statefulSet, nil
 }
 
-func (c *Cluster) scaleDown(newStatefulSet *v1beta1.StatefulSet) error {
-	podName := fmt.Sprintf("%s-0", c.Statefulset.Name) //TODO:
+func getPodNumb(podName string) (int32, error) {
+	parts := strings.Split(podName, "-")
+	if len(parts) == 0 {
+		return 0, fmt.Errorf("no postfix")
+	}
+
+	postfix := parts[len(parts)-1]
+	res, err := strconv.ParseInt(postfix, 10, 64)
+	if err != nil {
+		return 0, fmt.Errorf("couldn not parse postfix: %v", err)
+	}
+
+	return int32(res), nil
+}
+
+func (c *Cluster) preScaleDown(newStatefulSet *v1beta1.StatefulSet) error {
+	masterPod, err := c.getRolePods(Master)
+	if err != nil {
+		return fmt.Errorf("could not get master pod: %v", err)
+	}
+
+	podNum, err := getPodNumb(masterPod[0].Name)
+	if err != nil {
+		return fmt.Errorf("could not get pod number: %v", err)
+	}
+
+	//Check if scale down affects current master pod
+	if (*c.Statefulset.Spec.Replicas < podNum+1) ||
+		(*newStatefulSet.Spec.Replicas > podNum+1) {
+		return nil
+	}
+
+	podName := fmt.Sprintf("%s-0", c.Statefulset.Name)
 	masterCandidatePod, err := c.KubeClient.Pods(c.OpConfig.Namespace).Get(podName, metav1.GetOptions{})
 	if err != nil {
 		return fmt.Errorf("could not get master candidate pod: %v", err)
 	}
 
-	//TODO: check if the pod is master pod
+	if c.podSpiloRole(masterCandidatePod) == string(Master) {
+		return nil
+	}
 
 	// some sanity check
 	if !util.MapContains(masterCandidatePod.Labels, c.OpConfig.ClusterLabels) ||
-		!util.MapContains(masterCandidatePod.Labels, map[string]string{c.OpConfig.ClusterNameLabel:c.Name}) {
+		!util.MapContains(masterCandidatePod.Labels, map[string]string{c.OpConfig.ClusterNameLabel: c.Name}) {
 		return fmt.Errorf("pod %q does not belong to cluster", podName)
 	}
 
-	masterPod, err := c.getRolePods(Master)
-	if err != nil {
-		return fmt.Errorf("could not get master pod: %v", err)
-	}
-
 	if err := c.patroni.Failover(&masterPod[0], masterCandidatePod.Name); err != nil {
 		return fmt.Errorf("could not failover: %v", err)
 	}
@@ -153,18 +183,19 @@ func (c *Cluster) updateStatefulSet(newStatefulSet *v1beta1.StatefulSet) error {
 	}
 	statefulSetName := util.NameFromMeta(c.Statefulset.ObjectMeta)
 
+	//scale down
+	if *c.Statefulset.Spec.Replicas > *newStatefulSet.Spec.Replicas {
+		if err := c.preScaleDown(newStatefulSet); err != nil {
+			return fmt.Errorf("could not scale down: %v", err)
+		}
+	}
 	c.logger.Debugf("updating statefulset")
 
 	patchData, err := specPatch(newStatefulSet.Spec)
 	if err != nil {
 		return fmt.Errorf("could not form patch for the statefulset %q: %v", statefulSetName, err)
 	}
 
-	//Scale down
-	if *c.Statefulset.Spec.Replicas > *newStatefulSet.Spec.Replicas {
-		c.scaleDown(newStatefulSet)
-	}
-
 	statefulSet, err := c.KubeClient.StatefulSets(c.Statefulset.Namespace).Patch(
 		c.Statefulset.Name,
 		types.MergePatchType,