Fixes the most apparent flaw that triggers #31 split brain

10conf-d.yml

@@ -145,6 +145,13 @@ data:
           set -x
         fi
       }
+    else
+      getent hosts mariadb-ready
+      [ $? -eq 2 ] && {
+        echo "This is NOT the 1st statefulset pod. Must not go up as primary."
+        echo "Found no ready pods. Will exit to trigger a crash loop back off."
+        exit 1
+      }
     fi
 
     # https://github.com/docker-library/mariadb/blob/master/10.2/docker-entrypoint.sh#L62

21mariadb-ready-service.yml

@@ -0,0 +1,14 @@
+# Used with `getent hosts` to check how many pods that are ready
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: mariadb-ready
+  namespace: mysql
+  annotations:
+    service.alpha.kubernetes.io/tolerate-unready-endpoints: "false"
+spec:
+  publishNotReadyAddresses: false
+  clusterIP: None
+  selector:
+    app: mariadb

kustomization.yaml

@@ -1,5 +1,6 @@
 resources:
 - 10conf-d.yml
 - 20mariadb-service.yml
+- 21mariadb-ready-service.yml
 - 30mysql-service.yml
 - 50mariadb.yml