Add k8s provider option to create services without endpoints

docs/content/providers/kubernetes-ingress.md

@@ -440,6 +440,30 @@ providers:
 --providers.kubernetesingress.throttleDuration=10s
 ```
 
+### `allowEmptyServices`
+
+_Optional, Default: false
+
+```toml tab="File (TOML)"
+[providers.kubernetesIngress]
+  allowEmptyServices = true
+  # ...
+```
+
+```yaml tab="File (YAML)"
+providers:
+  kubernetesIngress:
+    allowEmptyServices: true
+    # ...
+```
+
+```bash tab="CLI"
+--providers.kubernetesingress.allowEmptyServices=true
+```
+
+Allow the creation of services if there are no endpoints available.
+This results in `503` http responses instead of `404`.
+
 ### Further
 
 To learn more about the various aspects of the Ingress specification that Traefik supports,

docs/content/reference/static-configuration/cli-ref.md

@@ -624,6 +624,9 @@ Kubernetes bearer token (not needed for in-cluster client).
 `--providers.kubernetesingress`:  
 Enable Kubernetes backend with default settings. (Default: ```false```)
 
+`--providers.kubernetesingress.allowemptyservices`:  
+Allow creation of services without endpoints. (Default: ```false```)
+
 `--providers.kubernetesingress.certauthfilepath`:  
 Kubernetes certificate authority file path (not needed for in-cluster client).
 

docs/content/reference/static-configuration/env-ref.md

@@ -624,6 +624,9 @@ Kubernetes bearer token (not needed for in-cluster client).
 `TRAEFIK_PROVIDERS_KUBERNETESINGRESS`:  
 Enable Kubernetes backend with default settings. (Default: ```false```)
 
+`TRAEFIK_PROVIDERS_KUBERNETESINGRESS_ALLOWEMPTYSERVICES`:  
+Allow creation of services without endpoints. (Default: ```false```)
+
 `TRAEFIK_PROVIDERS_KUBERNETESINGRESS_CERTAUTHFILEPATH`:  
 Kubernetes certificate authority file path (not needed for in-cluster client).
 

docs/content/reference/static-configuration/file.toml

@@ -106,6 +106,7 @@
     labelSelector = "foobar"
     ingressClass = "foobar"
     throttleDuration = "42s"
+    allowEmptyServices = true
     [providers.kubernetesIngress.ingressEndpoint]
       ip = "foobar"
       hostname = "foobar"

docs/content/reference/static-configuration/file.yaml

@@ -114,6 +114,7 @@ providers:
     labelSelector: foobar
     ingressClass: foobar
     throttleDuration: 42s
+    allowEmptyServices: true
     ingressEndpoint:
       ip: foobar
       hostname: foobar