EVEREST-203 draft ideas

commands/provision.go

@@ -23,7 +23,7 @@ import (
 	"github.com/percona/percona-everest-cli/commands/provision"
 )
 
-func newProvisionCmd(l *zap.SugaredLogger) *cobra.Command {
+func newProvisionCmd(l *zap.SugaredLogger) *cobra.Command { //nolint:deadcode,unused
 	cmd := &cobra.Command{
 		Use: "provision",
 	}

pkg/install/operators.go

@@ -245,6 +245,10 @@ func (o *Operators) checkEverestConnection(ctx context.Context) error {
 }
 
 func (o *Operators) performProvisioning(ctx context.Context) error {
+	if err := o.checkPreviousInstallations(ctx); err != nil {
+		return err
+	}
+
 	if err := o.provisionNamespace(); err != nil {
 		return err
 	}
@@ -661,6 +665,7 @@ func (o *Operators) runOperatorsWizard() error {
 // provisionNamespace provisions a namespace for Everest.
 func (o *Operators) provisionNamespace() error {
 	o.l.Infof("Creating namespace %s", o.config.Namespace)
+
 	err := o.kubeClient.CreateNamespace(o.config.Namespace)
 	if err != nil {
 		return errors.Join(err, errors.New("could not provision namespace"))
@@ -670,6 +675,24 @@ func (o *Operators) provisionNamespace() error {
 	return nil
 }
 
+func (o *Operators) checkPreviousInstallations(ctx context.Context) error {
+	// check if the current cluster already registered in Everest (by its uid)
+	// if it's NOT registred, run the below check:
+
+	o.l.Info("Checking existing Everest components")
+	namespaces, err := o.kubeClient.ListNamespaces(ctx)
+	if err != nil {
+		return errors.Join(err, errors.New("could not list namespaces"))
+	}
+	for _, ns := range namespaces {
+		if ns == o.config.Namespace {
+			return errors.New("please clean up the old installation of Everest first")
+		}
+	}
+
+	return nil
+}
+
 // provisionAllOperators provisions all configured operators to a k8s cluster.
 func (o *Operators) provisionAllOperators(ctx context.Context) error {
 	o.l.Info("Started provisioning the cluster")
@@ -792,6 +815,9 @@ func (o *Operators) connectToEverest(ctx context.Context) (*client.KubernetesClu
 
 	o.l.Info("Connecting your Kubernetes cluster to Everest")
 
+	// list clusters
+	// check the current uid is there, if so, skip the registration
+
 	k, err := o.everestClient.RegisterKubernetesCluster(ctx, client.CreateKubernetesClusterParams{
 		Kubeconfig: base64.StdEncoding.EncodeToString([]byte(kubeconfig)),
 		Name:       o.config.Name,

pkg/kubernetes/client/client.go

@@ -999,6 +999,21 @@ func (c *Client) CreateNamespace(name string) error {
 	return c.ApplyObject(n)
 }
 
+// ListNamespaces lists the existing namespaces.
+func (c *Client) ListNamespaces(ctx context.Context) ([]string, error) {
+	list, err := c.clientset.CoreV1().Namespaces().List(ctx, metav1.ListOptions{})
+	if err != nil {
+		return nil, err
+	}
+
+	namespaces := make([]string, 0, len(list.Items))
+	for _, ns := range list.Items {
+		namespaces = append(namespaces, ns.Name)
+	}
+
+	return namespaces, nil
+}
+
 // GetOperatorGroup retrieves an operator group details by namespace and name.
 func (c *Client) GetOperatorGroup(ctx context.Context, namespace, name string) (*v1.OperatorGroup, error) {
 	operatorClient, err := versioned.NewForConfig(c.restConfig)

pkg/kubernetes/kubernetes.go

@@ -574,6 +574,11 @@ func (k *Kubernetes) CreateNamespace(name string) error {
 	return k.client.CreateNamespace(name)
 }
 
+// ListNamespaces creates a new namespace.
+func (k *Kubernetes) ListNamespaces(ctx context.Context) ([]string, error) {
+	return k.client.ListNamespaces(ctx)
+}
+
 // InstallOperatorRequest holds the fields to make an operator install request.
 type InstallOperatorRequest struct {
 	Namespace              string