Only consider running Pods for scheduled backups

Though the scheduled backup code would bail if it found multiple
pgBackRest repository Pods, this ensures that only running
pgBackRest Pods would be considered.

Issue: #2237

Author: jkatz

pgo-scheduler/scheduler/pgbackrest.go

@@ -21,8 +21,10 @@ import (
 
 	"github.com/crunchydata/postgres-operator/internal/config"
 	log "github.com/sirupsen/logrus"
+	v1 "k8s.io/api/core/v1"
 	kerrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/util/wait"
 )
 
@@ -113,17 +115,20 @@ func (b BackRestBackupJob) Run() {
 		return
 	}
 
-	selector := fmt.Sprintf("%s=%s,pgo-backrest-repo=true", config.LABEL_PG_CLUSTER, b.cluster)
-	pods, err := clientset.CoreV1().Pods(b.namespace).List(metav1.ListOptions{LabelSelector: selector})
+	selector := fmt.Sprintf("%s=%s,%s", config.LABEL_PG_CLUSTER, b.cluster, config.LABEL_PGO_BACKREST_REPO)
+	options := metav1.ListOptions{
+		FieldSelector: fields.OneTermEqualSelector("status.phase", string(v1.PodRunning)).String(),
+		LabelSelector: selector,
+	}
+
+	pods, err := clientset.CoreV1().Pods(b.namespace).List(options)
 	if err != nil {
 		contextLogger.WithFields(log.Fields{
 			"selector": selector,
 			"error":    err,
 		}).Error("error getting pods from selector")
 		return
-	}
-
-	if len(pods.Items) != 1 {
+	} else if len(pods.Items) != 1 {
 		contextLogger.WithFields(log.Fields{
 			"selector":  selector,
 			"error":     err,