Fix StatefulSet Pod creation for caches with a long upstream

pkg/component/registrycaches/export_test.go

@@ -0,0 +1,17 @@
+// Copyright (c) 2024 SAP SE or an SAP affiliate company. All rights reserved. This file is licensed under the Apache Software License, v. 2 except as noted otherwise in the LICENSE file
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package registrycaches
+
+var ComputeName = computeName

pkg/component/registrycaches/registry_caches.go

@@ -276,7 +276,7 @@ func (r *registryCaches) computeResourcesDataForRegistryCache(ctx context.Contex
 	)
 
 	var (
-		name         = strings.Replace(fmt.Sprintf("registry-%s", cache.Upstream), ".", "-", -1)
+		name         = computeName(cache.Upstream)
 		configValues = map[string]interface{}{
 			"http_addr":              fmt.Sprintf(":%d", constants.RegistryCachePort),
 			"http_debug_addr":        fmt.Sprintf(":%d", debugPort),
@@ -513,3 +513,26 @@ func getLabels(name, upstream string) map[string]string {
 		constants.UpstreamHostLabel: upstream,
 	}
 }
+
+// computeName computes a name by given upstream.
+// The name later on is used by the registry cache Service, config Secret, StatefulSet and VPA.
+//
+// If length of registry-<escaped_upsteam> is NOT > 52, the name is registry-<escaped_upsteam>.
+// Otherwise it is registry-<truncated_escaped_upsteam>-<hash> where <escaped_upsteam> is truncated at 37 chars.
+// The returned name is at most 52 chars.
+func computeName(upstream string) string {
+	// The StatefulSet name limit is 63 chars. However Pods for a StatefulSet with name > 52 chars cannot be created due to https://github.com/kubernetes/kubernetes/issues/64023.
+	// The "controller-revision-hash" label gets added to the StatefulSet Pod. The label value is in format <stateful_set_name>_<hash> where <hash> is 10 or 11 chars.
+	// A label value limit is 63 chars. That's why a Pod for a StatefulSet with name > 52 chars cannot be created.
+	const statefulSetNameLimit = 52
+
+	escapedUpstream := strings.Replace(upstream, ".", "-", -1)
+	name := "registry-" + escapedUpstream
+	if len(name) > statefulSetNameLimit {
+		hash := utils.ComputeSHA256Hex([]byte(upstream))[:5]
+		upstreamLimit := statefulSetNameLimit - len("registry-") - len(hash) - 1
+		name = fmt.Sprintf("registry-%s-%s", escapedUpstream[:upstreamLimit], hash)
+	}
+
+	return name
+}

pkg/component/registrycaches/registry_caches_test.go

@@ -707,6 +707,17 @@ metadata:
 			})
 		})
 	})
+
+	DescribeTable("#computeName",
+		func(upstream, expected string) {
+			actual := ComputeName(upstream)
+			Expect(len(actual)).NotTo(BeNumerically(">", 52))
+			Expect(actual).To(Equal(expected))
+		},
+
+		Entry("short upstream", "docker.io", "registry-docker-io"),
+		Entry("long upstream", "myproj-releases.common.repositories.cloud.com", "registry-myproj-releases-common-repositories-c-3f834"),
+	)
 })
 
 func encodeBase64(val string) string {