[Feature] Switch ID to be IP based (#800)

Author: ajanikow

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [master](https://github.com/arangodb/kube-arangodb/tree/master) (N/A)
 - Replace `beta.kubernetes.io/arch` Pod label with `kubernetes.io/arch` using Silent Rotation
 - Add "Short Names" feature
+- Switch ArangoDB Image Discovery process from Headless Service to Pod IP
 
 ## [1.2.3](https://github.com/arangodb/kube-arangodb/tree/1.2.3) (2021-09-24)
 - Update UBI Image to 8.4

pkg/deployment/images.go

@@ -170,7 +170,7 @@ func (ib *imagesBuilder) fetchArangoDBImageIDAndVersion(ctx context.Context, cac
 		}
 
 		// Try fetching the ArangoDB version
-		client, err := arangod.CreateArangodImageIDClient(ctx, ib.APIObject, role, id)
+		client, err := arangod.CreateArangodImageIDClient(ctx, ib.APIObject, pod.Status.PodIP)
 		if err != nil {
 			log.Warn().Err(err).Msg("Failed to create Image ID Pod client")
 			return true, nil

pkg/util/arangod/client.go

@@ -168,10 +168,9 @@ func CreateArangodDatabaseClient(ctx context.Context, cli corev1.CoreV1Interface
 
 // CreateArangodImageIDClient creates a go-driver client for an ArangoDB instance
 // running in an Image-ID pod.
-func CreateArangodImageIDClient(ctx context.Context, deployment k8sutil.APIObject, role, id string) (driver.Client, error) {
+func CreateArangodImageIDClient(ctx context.Context, deployment k8sutil.APIObject, ip string) (driver.Client, error) {
 	// Create connection
-	dnsName := k8sutil.CreatePodDNSNameWithDomain(deployment, nil, role, id)
-	c, err := createArangodClientForDNSName(ctx, nil, nil, dnsName, false)
+	c, err := createArangodClientForDNSName(ctx, nil, nil, ip, false)
 	if err != nil {
 		return nil, errors.WithStack(err)
 	}