5ef0be2f58
Upon reconsidering as to the purpose of the test i.e to test the lock contention flags (--lock-file-contention and --lock-file), it makes sense that we test only the actual functionality which is the kubelet should stop once there is a lock contention. In no way it is the responsiblity of the kubelet to restart, which would be the responsiblity of a higher system such as systemd. Hence the removal of the check for releasing the lock and checking for whether the kubelet is healthy again or not seem out of scope from kubelet's responsiblities. Signed-off-by: Imran Pochi <imran@kinvolk.io>
76 lines
3.2 KiB
Go
76 lines
3.2 KiB
Go
//go:build linux
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// +build linux
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/*
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Copyright 2021 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package e2enode
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import (
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"time"
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"golang.org/x/sys/unix"
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"github.com/onsi/ginkgo"
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"github.com/onsi/gomega"
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"k8s.io/kubernetes/test/e2e/framework"
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)
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const contentionLockFile = "/var/run/kubelet.lock"
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// Kubelet Lock contention tests the lock contention feature.
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// Disruptive because the kubelet is restarted in the test.
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// NodeSpecialFeature:LockContention because we don't want the test to be picked up by any other
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// test suite, hence the unique name "LockContention".
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var _ = SIGDescribe("Lock contention [Slow] [Disruptive] [NodeSpecialFeature:LockContention]", func() {
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// Requires `--lock-file` & `--exit-on-lock-contention` flags to be set on the Kubelet.
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ginkgo.It("Kubelet should stop when the test acquires the lock on lock file and restart once the lock is released", func() {
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ginkgo.By("perform kubelet health check to check if kubelet is healthy and running.")
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// Precautionary check that kubelet is healthy before running the test.
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gomega.Expect(kubeletHealthCheck(kubeletHealthCheckURL)).To(gomega.BeTrue())
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ginkgo.By("acquiring the lock on lock file i.e /var/run/kubelet.lock")
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// Open the file with the intention to acquire the lock, this would imitate the behaviour
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// of the another kubelet(self-hosted) trying to start. When this lock contention happens
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// it is expected that the running kubelet must terminate and wait until the lock on the
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// lock file is released.
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// Kubelet uses the same approach to acquire the lock on lock file as shown here:
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// https://github.com/kubernetes/kubernetes/blob/9d2b361ebc7ef28f7cb75596ef40b7c239732d37/cmd/kubelet/app/server.go#L512-#L523
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// and the function definition of Acquire is here:
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// https://github.com/kubernetes/kubernetes/blob/9d2b361ebc7ef28f7cb75596ef40b7c239732d37/pkg/util/flock/flock_unix.go#L26
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fd, err := unix.Open(contentionLockFile, unix.O_CREAT|unix.O_RDWR|unix.O_CLOEXEC, 0600)
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framework.ExpectNoError(err)
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// Defer the lock release in case test fails and we don't reach the step of the release
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// lock. This ensures that we release the lock for sure.
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defer func() {
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err = unix.Flock(fd, unix.LOCK_UN)
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framework.ExpectNoError(err)
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}()
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// Acquire lock.
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err = unix.Flock(fd, unix.LOCK_EX)
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framework.ExpectNoError(err)
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ginkgo.By("verifying the kubelet is not healthy as there was a lock contention.")
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// Once the lock is acquired, check if the kubelet is in healthy state or not.
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// It should not be as the lock contention forces the kubelet to stop.
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gomega.Eventually(func() bool {
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return kubeletHealthCheck(kubeletHealthCheckURL)
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}, 10*time.Second, time.Second).Should(gomega.BeFalse())
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})
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})
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