Workaround the improper behavior of MySQL shell with respect to

auto_increment_offset and auto_increment_increment values override.

Signed-off-by: Gianluca Borello <g.borello@gmail.com>

Author: gianlucaborello

pkg/controllers/cluster/manager/cluster_manager.go

@@ -261,6 +261,14 @@ func (m *ClusterManager) handleInstanceMissing(ctx context.Context, primaryAddr
 			glog.Errorf("Failed to rejoin cluster: %v", err)
 			return false
 		}
+
+		if !m.Instance.MultiMaster {
+			err = m.localMySh.SetSinglePrimaryAutoIncrementParams(ctx)
+			if err != nil {
+				glog.Errorf("Failed setting auto increment parameters: %v", err)
+				return false
+			}
+		}
 	} else {
 		glog.V(4).Infof("Removing instance from cluster")
 		if err := primarySh.RemoveInstanceFromCluster(ctx, m.Instance.GetShellURI(), mysqlsh.Options{"force": "True"}); err != nil {
@@ -290,6 +298,15 @@ func (m *ClusterManager) handleInstanceNotFound(ctx context.Context, primaryAddr
 		glog.Errorf("Failed to add to cluster: %v", err)
 		return false
 	}
+
+	if !m.Instance.MultiMaster {
+		err = m.localMySh.SetSinglePrimaryAutoIncrementParams(ctx)
+		if err != nil {
+			glog.Errorf("Failed setting auto increment parameters: %v", err)
+			return false
+		}
+	}
+
 	return true
 }
 
@@ -327,6 +344,14 @@ func (m *ClusterManager) createCluster(ctx context.Context) (*innodb.ClusterStat
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to create new cluster")
 	}
+
+	if !m.Instance.MultiMaster {
+		err = m.localMySh.SetSinglePrimaryAutoIncrementParams(ctx)
+		if err != nil {
+			return nil, errors.Wrap(err, "failed setting auto increment parameters")
+		}
+	}
+
 	return status, nil
 }
 
@@ -342,6 +367,14 @@ func (m *ClusterManager) rebootFromOutage(ctx context.Context) (*innodb.ClusterS
 	if err != nil {
 		return nil, errors.Wrap(err, "getting cluster status")
 	}
+
+	if !m.Instance.MultiMaster {
+		err = m.localMySh.SetSinglePrimaryAutoIncrementParams(ctx)
+		if err != nil {
+			return nil, errors.Wrap(err, "failed setting auto increment parameters")
+		}
+	}
+
 	return status, nil
 }
 

pkg/util/mysqlsh/mysqlsh.go

@@ -55,6 +55,9 @@ type Interface interface {
 	// RebootClusterFromCompleteOutage recovers a cluster when all of its members
 	// have failed.
 	RebootClusterFromCompleteOutage(ctx context.Context) error
+	// SetSinglePrimaryAutoIncrementParams sets auto increment parameters to 1 and
+	// it should be called in single primary mode.
+	SetSinglePrimaryAutoIncrementParams(ctx context.Context) error
 }
 
 // errorRegex is used to parse Python tracebacks generated by mysql-shell.
@@ -226,6 +229,31 @@ func (r *runner) RebootClusterFromCompleteOutage(ctx context.Context) error {
 	return err
 }
 
+func (r *runner) SetSinglePrimaryAutoIncrementParams(ctx context.Context) error {
+	// Restore auto_increment_offset and auto_increment_increment
+	// to a safe 1 value, since we are in single primary mode.
+	// There seems to be a bug in MySQL Shell, and it initializes
+	// them to 7 and 1+id%7, which is not ideal. Also, from MySQL 8,
+	// MySQL will not overwrite these values according to
+	// group_replication_auto_increment_increment and its default of 7,
+	// so there's a wrong MySQL Shell assumption
+	// (https://github.com/mysql/mysql-server/commit/846ced27f8315a4697405b2b9a7bdeadb44cf070)
+
+	python := fmt.Sprintf("session.query('SET PERSIST auto_increment_offset = 1')")
+	_, err := r.run(ctx, python)
+	if err != nil {
+		return err
+	}
+
+	python = fmt.Sprintf("session.query('SET PERSIST auto_increment_increment = 1')")
+	_, err = r.run(ctx, python)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
 // Error holds errors from mysql-shell commands.
 type Error struct {
 	error