Generate correct output on NumCPU() when using cgroups2 (#11778)

Co-authored-by: Nicholas Orlowsky <nickorlow@nickorlow.com>

test/e2e/cgroups/cgroups.go

@@ -0,0 +1,115 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+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 cgroups
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+
+	"github.com/onsi/ginkgo/v2"
+	"github.com/stretchr/testify/assert"
+
+	"k8s.io/ingress-nginx/test/e2e/framework"
+
+	"k8s.io/ingress-nginx/pkg/util/runtime"
+)
+
+var _ = framework.IngressNginxDescribeSerial("[CGroups] cgroups", func() {
+	f := framework.NewDefaultFramework("cgroups")
+
+	ginkgo.BeforeEach(func() {
+		f.NewEchoDeployment()
+		f.NewSlowEchoDeployment()
+	})
+
+	ginkgo.It("detects cgroups version v1", func() {
+		cgroupPath := "/testing/sys/fs/cgroup/"
+		if err := os.MkdirAll(cgroupPath, os.ModePerm); err != nil {
+			log.Fatal(err)
+		}
+
+		quotaFile, err := os.Create(filepath.Join(cgroupPath, "cpu.cfs_quota_us"))
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		periodFile, err := os.Create(filepath.Join(cgroupPath, "cpu.cfs_period_us"))
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		_, err = quotaFile.WriteString("4")
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		err = quotaFile.Sync()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		_, err = periodFile.WriteString("2")
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		err = periodFile.Sync()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		assert.Equal(ginkgo.GinkgoT(), runtime.GetCgroupVersion(cgroupPath), int64(1))
+		assert.Equal(ginkgo.GinkgoT(), runtime.NumCPUWithCustomPath(cgroupPath), 2)
+
+		os.Remove(filepath.Join(cgroupPath, "cpu.cfs_quota_us"))
+		os.Remove(filepath.Join(cgroupPath, "cpu.cfs_period_us"))
+	})
+
+	ginkgo.It("detect cgroups version v2", func() {
+		cgroupPath := "/testing/sys/fs/cgroup/"
+		if err := os.MkdirAll(cgroupPath, os.ModePerm); err != nil {
+			log.Fatal(err)
+		}
+
+		_, err := os.Create(filepath.Join(cgroupPath, "cgroup.controllers"))
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		file, err := os.Create(filepath.Join(cgroupPath, "cpu.max"))
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		_, err = file.WriteString("4 2")
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		err = file.Sync()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		assert.Equal(ginkgo.GinkgoT(), runtime.GetCgroupVersion(cgroupPath), int64(2))
+		assert.Equal(ginkgo.GinkgoT(), runtime.NumCPUWithCustomPath(cgroupPath), 2)
+
+		os.Remove(filepath.Join(cgroupPath, "cpu.max"))
+		os.Remove(filepath.Join(cgroupPath, "cgroup.controllers"))
+	})
+})

test/e2e/e2e.go

@@ -32,6 +32,7 @@ import (
 	_ "k8s.io/ingress-nginx/test/e2e/admission"
 	_ "k8s.io/ingress-nginx/test/e2e/annotations"
 	_ "k8s.io/ingress-nginx/test/e2e/annotations/modsecurity"
+	_ "k8s.io/ingress-nginx/test/e2e/cgroups"
 	_ "k8s.io/ingress-nginx/test/e2e/dbg"
 	_ "k8s.io/ingress-nginx/test/e2e/defaultbackend"
 	_ "k8s.io/ingress-nginx/test/e2e/disableleaderelection"