Update doc, comments, flakyness and fix code review

Author: AMecea

docs/integrate-operator.md

@@ -22,7 +22,7 @@ The MySQL operator provides 3 services to access the nodes:
  * `<cluster_name>-mysql-master` is the service that points to the master node and this endpoint
    should be used for writes. This service is usually used to construct the DSN.
 
- * `<cluster_name>-mysql` is the service that routes traffic to all the _healthy_ nodes from the
+ * `<cluster_name>-mysql` is the service that routes traffic to _all healthy_ nodes from the
    cluster. You should use this endpoint for reads.
 
  * `mysql` is the service used internally to access all nodes within a namespace. You can use this

docs/operator-upgrades.md

@@ -33,9 +33,9 @@ This upgrade requires a Kubernetes cluster upgrade because the `v0.2.x` works on
 
 ## v0.3.x upgrade
 
-This version works on Kubernetes grater or equal with `1.11`. The upgrade should be done on staging
+This version requires at list Kubernetes `1.11`. The upgrade should be tried on staging environment
 first because it's with downtime. It requires the deletion of the statefulset and recreation of it.
-The reason behind is that we changed the headless service name (which is an invariant statefulset
+The reason behind is that we changed the headless service name (which is an immutable statefulset
 field) to make it smaller that will prevent you from hitting this
 [bug](https://github.com/presslabs/mysql-operator/issues/170).
 

pkg/apis/mysql/v1alpha1/zz_generated.deepcopy.go

@@ -282,7 +282,7 @@ func (s *sfsSyncer) ensureContainersSpec() []core.Container {
 				fmt.Sprintf("--defaults-file=%s", confClientPath),
 				"-e",
 				// nolint: gosec
-				fmt.Sprintf("SELECT * FROM %s.%s WHERE name='configured' AND value='1'",
+				fmt.Sprintf("SELECT true as 'ready' FROM %s.%s WHERE name='configured' AND value='1'",
 					constants.OperatorDbName, constants.OperatorStatusTableName),
 			},
 		},

pkg/apis/mysql/v1alpha1/zz_generated.defaults.go

@@ -119,6 +119,8 @@ var _ = Describe("MysqlNode controller", func() {
 			By("create the MySQL cluster")
 			Expect(c.Create(context.TODO(), secret)).To(Succeed())
 			Expect(c.Create(context.TODO(), cluster.Unwrap())).To(Succeed())
+			// ensure that cluster is created, else test may be flaky
+			Eventually(testutil.RefreshFn(c, cluster.Unwrap())).ShouldNot(BeNil())
 
 			By("create MySQL pod")
 			getOrCreatePod(c, cluster, 0)

pkg/controller/mysqlcluster/internal/syncer/statefullset.go

@@ -246,7 +246,6 @@ func (r *nodeSQLRunner) readStatusValue(ctx context.Context, key string) (string
 
 	var value string
 	if err := r.readFromMysql(ctx, qq, &value); err != nil {
-		// if no rows found then continue to add GTID purged
 		if err != sql.ErrNoRows {
 			return "", err
 		}

pkg/controller/node/node_ctrl_test.go

@@ -33,15 +33,15 @@ func (c *MysqlCluster) Validate() error {
 
 	// volume spec should be specified on the cluster
 	vs := c.Spec.VolumeSpec
-	if anyNull(vs.PersistentVolumeClaim, vs.HostPath, vs.EmptyDir) {
+	if anyIsNull(vs.PersistentVolumeClaim, vs.HostPath, vs.EmptyDir) {
 		return fmt.Errorf("no .spec.volumeSpec is specified")
 	}
 
 	return nil
 }
 
 // anyNull checks if any of the given parameters is null and returns true if so
-func anyNull(vars ...interface{}) bool {
+func anyIsNull(vars ...interface{}) bool {
 	isNull := false
 	for _, v := range vars {
 		isNull = isNull || v == nil

pkg/controller/node/sql.go

@@ -185,7 +185,7 @@ func initFileQuery(cfg *Config, gtidPurged string) []byte {
 		CREATE TABLE IF NOT EXISTS %[1]s.%[2]s (
             name varchar(64) PRIMARY KEY,
             value varchar(512) NOT NULL
-		)`, constants.OperatorDbName, constants.OperatorStatusTableName))
+		) ENGINE=CSV `, constants.OperatorDbName, constants.OperatorStatusTableName))
 
 	// mark node as not configured at startup, the operator will mark it configured
 	// nolint: gosec

pkg/internal/mysqlcluster/validation.go

@@ -131,15 +131,6 @@ var _ = Describe("Mysql cluster tests", func() {
 	It("scale down a cluster", func() {
 		// configure MySQL cluster to have 2 replicas and to use PV for data storage
 		cluster.Spec.Replicas = &two
-		// cluster.Spec.VolumeSpec.EmptyDir = nil
-		// cluster.Spec.VolumeSpec.HostPath = nil
-		// cluster.Spec.VolumeSpec.PersistentVolumeClaim = &core.PersistentVolumeClaimSpec{
-		// 	Resources: core.ResourceRequirements{
-		// 		Requests: core.ResourceList{
-		// 			core.ResourceStorage: resource.MustParse("1Gi"),
-		// 		},
-		// 	},
-		// }
 		Expect(f.Client.Update(context.TODO(), cluster)).To(Succeed())
 
 		// test cluster to be ready