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Merge pull request #50646 from rickypai/rpai/hostalias_hostnetwork 

Automatic merge from submit-queue

Support HostAlias for HostNetwork Pods

**What this PR does / why we need it**: Currently, HostAlias does not support HostNetwork pods because historically, kubelet only manages hosts file for non-HostNetwork pods. With the recent change in https://github.com/kubernetes/kubernetes/pull/49140, kubelet now manages hosts file for all Pods, which enables HostAlias support also.

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #48398

**Special notes for your reviewer**: might be easier to review commit-by-commit

**Release note**:

```release-note
HostAlias is now supported for both non-HostNetwork Pods and HostNetwork Pods.
```

@yujuhong @hongchaodeng @thockin
pull/6/head
Kubernetes Submit Queue 2017-08-23 22:06:27 -07:00 committed by GitHub
parent 5cb1cccd40 1e7c0a4b0c
commit ef1b835220
4 changed files with 124 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
pkg/api/validation/validation.go
View File

@ -2103,16 +2103,6 @@ func validateHostNetwork(hostNetwork bool, containers []api.Container, fldPath *
return allErrors
}
func validateHostNetworkNoHostAliases(hostNetwork bool, hostAliases []api.HostAlias, fldPath *field.Path) field.ErrorList {
allErrors := field.ErrorList{}
if hostNetwork {
if len(hostAliases) > 0 {
allErrors = append(allErrors, field.Forbidden(fldPath, "may not be set when `hostNetwork` is true"))
}
}
return allErrors
}
// validateImagePullSecrets checks to make sure the pull secrets are well
// formed. Right now, we only expect name to be set (it's the only field). If
// this ever changes and someone decides to set those fields, we'd like to
@ -2649,7 +2639,6 @@ func ValidatePodSecurityContext(securityContext *api.PodSecurityContext, spec *a
if securityContext != nil {
allErrs = append(allErrs, validateHostNetwork(securityContext.HostNetwork, spec.Containers, specPath.Child("containers"))...)
allErrs = append(allErrs, validateHostNetworkNoHostAliases(securityContext.HostNetwork, spec.HostAliases, specPath)...)
if securityContext.FSGroup != nil {
for _, msg := range validation.IsValidGroupID(*securityContext.FSGroup) {
allErrs = append(allErrs, field.Invalid(fldPath.Child("fsGroup"), *(securityContext.FSGroup), msg))

17
pkg/api/validation/validation_test.go
View File

@ -3977,13 +3977,22 @@ func TestValidatePodSpec(t *testing.T) {
RestartPolicy: api.RestartPolicyAlways,
DNSPolicy: api.DNSClusterFirst,
},
{ // Populate HostAliases with `foo.bar` hostnames .
{ // Populate HostAliases with `foo.bar` hostnames.
HostAliases: []api.HostAlias{{IP: "12.34.56.78", Hostnames: []string{"host1.foo", "host2.bar"}}},
Volumes: []api.Volume{{Name: "vol", VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}}},
Containers: []api.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
RestartPolicy: api.RestartPolicyAlways,
DNSPolicy: api.DNSClusterFirst,
},
{ // Populate HostAliases with HostNetwork.
HostAliases: []api.HostAlias{{IP: "12.34.56.78", Hostnames: []string{"host1.foo", "host2.bar"}}},
Containers: []api.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
SecurityContext: &api.PodSecurityContext{
HostNetwork: true,
},
RestartPolicy: api.RestartPolicyAlways,
DNSPolicy: api.DNSClusterFirst,
},
{ // Populate PriorityClassName.
Volumes: []api.Volume{{Name: "vol", VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}}},
Containers: []api.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
@ -4056,12 +4065,6 @@ func TestValidatePodSpec(t *testing.T) {
RestartPolicy: api.RestartPolicyAlways,
DNSPolicy: api.DNSClusterFirst,
},
"with hostNetwork and hostAliases": {
SecurityContext: &api.PodSecurityContext{
HostNetwork: true,
},
HostAliases: []api.HostAlias{{IP: "12.34.56.78", Hostnames: []string{"host1", "host2"}}},
},
"with hostAliases with invalid IP": {
SecurityContext: &api.PodSecurityContext{
HostNetwork: false,

24
pkg/kubelet/kubelet_pods.go
View File

@ -233,7 +233,7 @@ func ensureHostsFile(fileName, hostIP, hostName, hostDomainName string, hostAlia
// if Pod is using host network, read hosts file from the node's filesystem.
// `etcHostsPath` references the location of the hosts file on the node.
// `/etc/hosts` for *nix systems.
hostsFileContent, err = nodeHostsFileContent(etcHostsPath)
hostsFileContent, err = nodeHostsFileContent(etcHostsPath, hostAliases)
if err != nil {
return err
}
@ -246,8 +246,13 @@ func ensureHostsFile(fileName, hostIP, hostName, hostDomainName string, hostAlia
}
// nodeHostsFileContent reads the content of node's hosts file.
func nodeHostsFileContent(hostsFilePath string) ([]byte, error) {
return ioutil.ReadFile(hostsFilePath)
func nodeHostsFileContent(hostsFilePath string, hostAliases []v1.HostAlias) ([]byte, error) {
hostsFileContent, err := ioutil.ReadFile(hostsFilePath)
if err != nil {
return nil, err
}
hostsFileContent = append(hostsFileContent, hostsEntriesFromHostAliases(hostAliases)...)
return hostsFileContent, nil
}
// managedHostsFileContent generates the content of the managed etc hosts based on Pod IP and other
@ -266,6 +271,19 @@ 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
}
func hostsEntriesFromHostAliases(hostAliases []v1.HostAlias) []byte {
if len(hostAliases) == 0 {
return []byte{}
}
var buffer bytes.Buffer
buffer.WriteString("\n")
buffer.WriteString("# Entries added by HostAliases.\n")
// write each IP/hostname pair as an entry into hosts file
for _, hostAlias := range hostAliases {
for _, hostname := range hostAlias.Hostnames {

98
pkg/kubelet/kubelet_pods_test.go
View File

@ -184,11 +184,23 @@ func TestMakeMounts(t *testing.T) {
func TestNodeHostsFileContent(t *testing.T) {
testCases := []struct {
hostsFileName string
expectedContent string
hostsFileName string
hostAliases []v1.HostAlias
rawHostsFileContent string
expectedHostsFileContent string
}{
{
"hosts_test_file1",
[]v1.HostAlias{},
`# hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
123.45.67.89 some.domain
`,
`# hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
@ -201,6 +213,16 @@ fe00::2 ip6-allrouters
},
{
"hosts_test_file2",
[]v1.HostAlias{},
`# another hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
12.34.56.78 another.domain
`,
`# another hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
@ -209,18 +231,80 @@ fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
12.34.56.78 another.domain
`,
},
{
"hosts_test_file1_with_host_aliases",
[]v1.HostAlias{
{IP: "123.45.67.89", Hostnames: []string{"foo", "bar", "baz"}},
},
`# hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
123.45.67.89 some.domain
`,
`# hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
123.45.67.89 some.domain
# Entries added by HostAliases.
123.45.67.89 foo
123.45.67.89 bar
123.45.67.89 baz
`,
},
{
"hosts_test_file2_with_host_aliases",
[]v1.HostAlias{
{IP: "123.45.67.89", Hostnames: []string{"foo", "bar", "baz"}},
{IP: "456.78.90.123", Hostnames: []string{"park", "doo", "boo"}},
},
`# another hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
12.34.56.78 another.domain
`,
`# another hosts file for testing.
127.0.0.1 localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
12.34.56.78 another.domain
# Entries added by HostAliases.
123.45.67.89 foo
123.45.67.89 bar
123.45.67.89 baz
456.78.90.123 park
456.78.90.123 doo
456.78.90.123 boo
`,
},
}
for _, testCase := range testCases {
tmpdir, err := writeHostsFile(testCase.hostsFileName, testCase.expectedContent)
tmpdir, err := writeHostsFile(testCase.hostsFileName, testCase.rawHostsFileContent)
require.NoError(t, err, "could not create a temp hosts file")
defer os.RemoveAll(tmpdir)
actualContent, fileReadErr := nodeHostsFileContent(filepath.Join(tmpdir, testCase.hostsFileName))
actualContent, fileReadErr := nodeHostsFileContent(filepath.Join(tmpdir, testCase.hostsFileName), testCase.hostAliases)
require.NoError(t, fileReadErr, "could not create read hosts file")
assert.Equal(t, testCase.expectedContent, string(actualContent), "hosts file content not expected")
assert.Equal(t, testCase.expectedHostsFileContent, string(actualContent), "hosts file content not expected")
}
}
@ -287,6 +371,8 @@ fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
203.0.113.1 podFoo.domainFoo podFoo
# Entries added by HostAliases.
123.45.67.89 foo
123.45.67.89 bar
123.45.67.89 baz
@ -308,6 +394,8 @@ fe00::0 ip6-mcastprefix
fe00::1 ip6-allnodes
fe00::2 ip6-allrouters
203.0.113.1 podFoo.domainFoo podFoo
# Entries added by HostAliases.
123.45.67.89 foo
123.45.67.89 bar
123.45.67.89 baz