Check etcd key availability for the new cluster

pkg/cluster/cluster.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/Sirupsen/logrus"
 	etcdclient "github.com/coreos/etcd/client"
+	"golang.org/x/net/context"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/pkg/api"
 	"k8s.io/client-go/pkg/api/v1"
@@ -131,7 +132,26 @@ func (c *Cluster) initUsers() error {
 	return nil
 }
 
+func (c *Cluster) etcdKeyExists(keyName string) (bool, error) {
+	options := etcdclient.GetOptions{}
+	resp, err := c.EtcdClient.Get(context.Background(), keyName, &options)
+	if err != nil {
+		if err.(etcdclient.Error).Code == etcdclient.ErrorCodeKeyNotFound {
+			return false, nil
+		}
+	}
+
+	return resp != nil, err
+}
+
 func (c *Cluster) Create() error {
+	keyExist, err := c.etcdKeyExists(fmt.Sprintf("/%s/%s", c.OpConfig.EtcdScope, c.Metadata.Name))
+	if err != nil {
+		return fmt.Errorf("Can't check etcd key: %s", err)
+	}
+	if keyExist {
+		return fmt.Errorf("Etcd key for the cluster already exists")
+	}
 	//TODO: service will create endpoint implicitly
 	ep, err := c.createEndpoint()
 	if err != nil {

pkg/controller/controller.go

@@ -60,10 +60,6 @@ func (c *Controller) Run(stopCh <-chan struct{}, wg *sync.WaitGroup) {
 	wg.Add(1)
 
 	c.initController()
-	if err := c.initEtcdClient(c.opConfig.EtcdHost); err != nil {
-		c.logger.Errorf("Can't get etcd client: %s", err)
-		return
-	}
 
 	c.logger.Infof("'%s' namespace will be watched", c.PodNamespace)
 	go c.runInformers(stopCh)
@@ -112,6 +108,10 @@ func (c *Controller) initController() {
 		UpdateFunc: c.podUpdate,
 		DeleteFunc: c.podDelete,
 	})
+
+	if err := c.initEtcdClient(c.opConfig.EtcdHost); err != nil {
+		c.logger.Fatalf("Can't get etcd client: %s", err)
+	}
 }
 
 func (c *Controller) runInformers(stopCh <-chan struct{}) {

pkg/util/config/config.go

@@ -3,6 +3,7 @@ package config
 import (
 	"encoding/json"
 	"fmt"
+	"strings"
 	"time"
 
 	"github.com/kelseyhightower/envconfig"
@@ -39,6 +40,8 @@ type Config struct {
 	DockerImage        string `split_words:"true" default:"registry.opensource.zalan.do/acid/spilo-9.6:1.2-p12"`
 	ServiceAccountName string `split_words:"true" default:"operator"`
 	DbHostedZone       string `split_words:"true" default:"db.example.com"`
+	EtcdScope          string `split_words:"true" default:"service"`
+	DebugLogging       bool   `split_words:"true" default:"false"`
 }
 
 func LoadFromEnv() *Config {
@@ -47,6 +50,7 @@ func LoadFromEnv() *Config {
 	if err != nil {
 		panic(fmt.Errorf("Can't read config: %v", err))
 	}
+	cfg.EtcdScope = strings.Trim(cfg.EtcdScope, "/")
 
 	return &cfg
 }