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Unverified Commit 93a2e8a4 authored by Kubernetes Submit Queue's avatar Kubernetes Submit Queue Committed by GitHub
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Merge pull request #64931 from dghubble/automated-cherry-pick-of-#61613-upstream-release-1.10

Automatic merge from submit-queue. Ensure /etc/hosts has a header always - Fix conformance test We have 2 scenarios where we copy /etc/hosts - with host network (we just copy the /etc/hosts from node) - without host network (create a fresh /etc/hosts from pod info) We are having trouble figuring out whether a /etc/hosts in a pod/container has been "fixed-up" or not. And whether we used host network or a fresh /etc/hosts in the various ways we start up the tests which are: - VM/box against a remote cluster - As a container inside the k8s cluster - DIND scenario in CI where test runs inside a managed container Please see previous mis-guided attempt to fix this problem at ba20e634 In this commit we revert the code from there as well. So we should make sure: - we always add a header if we touched the file - we add slightly different headers so we can figure out if we used the host network or not. Update the test case to inject /etc/hosts from node to another path (/etc/hosts-original) as well and use that to compare. **What this PR does / why we need it**: **Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*: Fixes # **Special notes for your reviewer**: **Release note**: ```release-note Rework Kubelet set `/etc/hosts` behavior to fix conformance testability ```
parents 6954fae8 00998d0e
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Showing with 83 additions and 52 deletions
pkg/kubelet/kubelet_pods.go
View file @ 93a2e8a4
......@@ -68,6 +68,11 @@ import (
"k8s.io/kubernetes/third_party/forked/golang/expansion"
)
const (
managedHostsHeader = "# Kubernetes-managed hosts file.\n"
managedHostsHeaderWithHostNetwork = "# Kubernetes-managed hosts file (host network).\n"
)
// Get a list of pods that have data directories.
func (kl *Kubelet) listPodsFromDisk() ([]types.UID, error) {
podInfos, err := ioutil.ReadDir(kl.getPodsDir())
......@@ -341,15 +346,18 @@ func nodeHostsFileContent(hostsFilePath string, hostAliases []v1.HostAlias) ([]b
if err != nil {
return nil, err
}
hostsFileContent = append(hostsFileContent, hostsEntriesFromHostAliases(hostAliases)...)
return hostsFileContent, nil
var buffer bytes.Buffer
buffer.WriteString(managedHostsHeaderWithHostNetwork)
buffer.Write(hostsFileContent)
buffer.Write(hostsEntriesFromHostAliases(hostAliases))
return buffer.Bytes(), nil
}
// managedHostsFileContent generates the content of the managed etc hosts based on Pod IP and other
// information.
func managedHostsFileContent(hostIP, hostName, hostDomainName string, hostAliases []v1.HostAlias) []byte {
var buffer bytes.Buffer
buffer.WriteString("# Kubernetes-managed hosts file.\n")
buffer.WriteString(managedHostsHeader)
buffer.WriteString("127.0.0.1\tlocalhost\n") // ipv4 localhost
buffer.WriteString("::1\tlocalhost ip6-localhost ip6-loopback\n") // ipv6 localhost
buffer.WriteString("fe00::0\tip6-localnet\n")
......@@ -361,9 +369,8 @@ func managedHostsFileContent(hostIP, hostName, hostDomainName string, hostAliase
} else {
buffer.WriteString(fmt.Sprintf("%s\t%s\n", hostIP, hostName))
}
hostsFileContent := buffer.Bytes()
hostsFileContent = append(hostsFileContent, hostsEntriesFromHostAliases(hostAliases)...)
return hostsFileContent
buffer.Write(hostsEntriesFromHostAliases(hostAliases))
return buffer.Bytes()
}
func hostsEntriesFromHostAliases(hostAliases []v1.HostAlias) []byte {
......
pkg/kubelet/kubelet_pods_test.go
View file @ 93a2e8a4
......@@ -519,7 +519,8 @@ fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
123.45.67.89 some.domain
`,
`# hosts file for testing.
`# Kubernetes-managed hosts file (host network).
# hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
......@@ -541,7 +542,8 @@ fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
12.34.56.78 another.domain
`,
`# another hosts file for testing.
`# Kubernetes-managed hosts file (host network).
# another hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
......@@ -565,7 +567,8 @@ fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
123.45.67.89 some.domain
`,
`# hosts file for testing.
`# Kubernetes-managed hosts file (host network).
# hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
......@@ -595,7 +598,8 @@ fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
12.34.56.78 another.domain
`,
`# another hosts file for testing.
`# Kubernetes-managed hosts file (host network).
# another hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
......
test/e2e/common/kubelet_etc_hosts.go
View file @ 93a2e8a4
......@@ -17,8 +17,6 @@ limitations under the License.
package common
import (
"io/ioutil"
"os"
"strings"
"time"
......@@ -34,6 +32,8 @@ const (
etcHostsPodName = "test-pod"
etcHostsHostNetworkPodName = "test-host-network-pod"
etcHostsPartialContent = "# Kubernetes-managed hosts file."
etcHostsPath = "/etc/hosts"
etcHostsOriginalPath = "/etc/hosts-original"
)
var etcHostsImageName = imageutils.GetE2EImage(imageutils.Netexec)
......@@ -42,7 +42,6 @@ type KubeletManagedHostConfig struct {
hostNetworkPod *v1.Pod
pod *v1.Pod
f *framework.Framework
tmpEtcHostFile *os.File
}
var _ = framework.KubeDescribe("KubeletManagedEtcHosts", func() {
......@@ -62,8 +61,6 @@ var _ = framework.KubeDescribe("KubeletManagedEtcHosts", func() {
By("Running the test")
config.verifyEtcHosts()
config.cleanup()
})
})
......@@ -81,26 +78,6 @@ func (config *KubeletManagedHostConfig) verifyEtcHosts() {
}
func (config *KubeletManagedHostConfig) setup() {
etcHostContents := `127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters`
// Write the data to a temp file.
var err error
config.tmpEtcHostFile, err = ioutil.TempFile("", "etc-hosts")
if err != nil {
framework.Failf("failed to create temp file for /etc/hosts: %v", err)
}
if _, err := config.tmpEtcHostFile.Write([]byte(etcHostContents)); err != nil {
framework.Failf("Failed to write temp file for /etc/hosts data: %v", err)
}
if err := config.tmpEtcHostFile.Close(); err != nil {
framework.Failf("Failed to close temp file: %v", err)
}
By("Creating hostNetwork=false pod")
config.createPodWithoutHostNetwork()
......@@ -108,12 +85,6 @@ ff02::2 ip6-allrouters`
config.createPodWithHostNetwork()
}
func (config *KubeletManagedHostConfig) cleanup() {
if config.tmpEtcHostFile != nil {
os.Remove(config.tmpEtcHostFile.Name())
}
}
func (config *KubeletManagedHostConfig) createPodWithoutHostNetwork() {
podSpec := config.createPodSpec(etcHostsPodName)
config.pod = config.f.PodClient().CreateSync(podSpec)
......@@ -137,16 +108,24 @@ func assertManagedStatus(
etcHostsContent := ""
for startTime := time.Now(); time.Since(startTime) < retryTimeout; {
etcHostsContent = config.getEtcHostsContent(podName, name)
isManaged := strings.Contains(etcHostsContent, etcHostsPartialContent)
if expectedIsManaged == isManaged {
return
etcHostsContent = config.getFileContents(podName, name, etcHostsPath)
etcHostsOriginalContent := config.getFileContents(podName, name, etcHostsOriginalPath)
// Make sure there is some content in both files
if len(etcHostsContent) > 0 && len(etcHostsOriginalContent) > 0 {
// if the files match, kubernetes did not touch the file at all
// if the file has the header, kubernetes is not using host network
// and is constructing the file based on Pod IP
isManaged := strings.HasPrefix(etcHostsContent, etcHostsPartialContent) &&
etcHostsContent != etcHostsOriginalContent
if expectedIsManaged == isManaged {
return
}
}
glog.Warningf(
"For pod: %s, name: %s, expected %t, actual %t (/etc/hosts was %q), retryCount: %d",
podName, name, expectedIsManaged, isManaged, etcHostsContent, retryCount)
"For pod: %s, name: %s, expected %t, (/etc/hosts was %q), (/etc/hosts-original was %q), retryCount: %d",
podName, name, expectedIsManaged, etcHostsContent, etcHostsOriginalContent, retryCount)
retryCount++
time.Sleep(100 * time.Millisecond)
......@@ -163,8 +142,8 @@ func assertManagedStatus(
}
}
func (config *KubeletManagedHostConfig) getEtcHostsContent(podName, containerName string) string {
return config.f.ExecCommandInContainer(podName, containerName, "cat", "/etc/hosts")
func (config *KubeletManagedHostConfig) getFileContents(podName, containerName, path string) string {
return config.f.ExecCommandInContainer(podName, containerName, "cat", path)
}
func (config *KubeletManagedHostConfig) createPodSpec(podName string) *v1.Pod {
......@@ -184,6 +163,12 @@ func (config *KubeletManagedHostConfig) createPodSpec(podName string) *v1.Pod {
"sleep",
"900",
},
VolumeMounts: []v1.VolumeMount{
{
Name: "host-etc-hosts",
MountPath: etcHostsOriginalPath,
},
},
},
{
Name: "busybox-2",
......@@ -193,6 +178,12 @@ func (config *KubeletManagedHostConfig) createPodSpec(podName string) *v1.Pod {
"sleep",
"900",
},
VolumeMounts: []v1.VolumeMount{
{
Name: "host-etc-hosts",
MountPath: etcHostsOriginalPath,
},
},
},
{
Name: "busybox-3",
......@@ -205,7 +196,11 @@ func (config *KubeletManagedHostConfig) createPodSpec(podName string) *v1.Pod {
VolumeMounts: []v1.VolumeMount{
{
Name: "host-etc-hosts",
MountPath: "/etc/hosts",
MountPath: etcHostsPath,
},
{
Name: "host-etc-hosts",
MountPath: etcHostsOriginalPath,
},
},
},
......@@ -215,7 +210,7 @@ func (config *KubeletManagedHostConfig) createPodSpec(podName string) *v1.Pod {
Name: "host-etc-hosts",
VolumeSource: v1.VolumeSource{
HostPath: &v1.HostPathVolumeSource{
Path: config.tmpEtcHostFile.Name(),
Path: etcHostsPath,
Type: hostPathType,
},
},
......@@ -227,6 +222,8 @@ func (config *KubeletManagedHostConfig) createPodSpec(podName string) *v1.Pod {
}
func (config *KubeletManagedHostConfig) createPodSpecWithHostNetwork(podName string) *v1.Pod {
hostPathType := new(v1.HostPathType)
*hostPathType = v1.HostPathType(string(v1.HostPathFileOrCreate))
pod := &v1.Pod{
ObjectMeta: metav1.ObjectMeta{
Name: podName,
......@@ -243,6 +240,12 @@ func (config *KubeletManagedHostConfig) createPodSpecWithHostNetwork(podName str
"sleep",
"900",
},
VolumeMounts: []v1.VolumeMount{
{
Name: "host-etc-hosts",
MountPath: etcHostsOriginalPath,
},
},
},
{
Name: "busybox-2",
......@@ -252,6 +255,23 @@ func (config *KubeletManagedHostConfig) createPodSpecWithHostNetwork(podName str
"sleep",
"900",
},
VolumeMounts: []v1.VolumeMount{
{
Name: "host-etc-hosts",
MountPath: etcHostsOriginalPath,
},
},
},
},
Volumes: []v1.Volume{
{
Name: "host-etc-hosts",
VolumeSource: v1.VolumeSource{
HostPath: &v1.HostPathVolumeSource{
Path: etcHostsPath,
Type: hostPathType,
},
},
},
},
},
......
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