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kubeadm: change in logic of getDNSIP

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This commit is contained in:
madhukar32 2017-09-05 16:47:16 -07:00 committed by Madhukar Nayakbomman
parent b983cee8b8
commit 359d81419c
5 changed files with 47 additions and 13 deletions
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1
cmd/kubeadm/app/cmd/phases/addons.go
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@ -116,6 +116,7 @@ func getAddonsSubCommands() []*cobra.Command {
if properties.use == "all" || properties.use == "kube-dns" {
cmd.Flags().StringVar(&cfg.Networking.DNSDomain, "service-dns-domain", cfg.Networking.DNSDomain, `Use alternative domain for services, e.g. "myorg.internal.`)
cmd.Flags().StringVar(&cfg.Networking.ServiceSubnet, "service-cidr", cfg.Networking.ServiceSubnet, `Use alternative range of IP address for service VIPs`)
}
subCmds = append(subCmds, cmd)
}

2
cmd/kubeadm/app/cmd/phases/addons_test.go
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@ -47,6 +47,7 @@ func TestAddonsSubCommandsHasFlags(t *testing.T) {
"apiserver-bind-port",
"pod-network-cidr",
"service-dns-domain",
"service-cidr",
},
},
{
@ -61,6 +62,7 @@ func TestAddonsSubCommandsHasFlags(t *testing.T) {
command: "kube-dns",
additionalFlags: []string{
"service-dns-domain",
"service-cidr",
},
},
}

1
cmd/kubeadm/app/phases/addons/dns/BUILD
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@ -41,6 +41,7 @@ go_library(
"//cmd/kubeadm/app/util:go_default_library",
"//cmd/kubeadm/app/util/apiclient:go_default_library",
"//pkg/api/legacyscheme:go_default_library",
"//pkg/registry/core/service/ipallocator:go_default_library",
"//pkg/util/version:go_default_library",
"//vendor/k8s.io/api/apps/v1beta2:go_default_library",
"//vendor/k8s.io/api/core/v1:go_default_library",

26
cmd/kubeadm/app/phases/addons/dns/dns.go
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@ -34,6 +34,7 @@ import (
kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
"k8s.io/kubernetes/pkg/api/legacyscheme"
"k8s.io/kubernetes/pkg/registry/core/service/ipallocator"
"k8s.io/kubernetes/pkg/util/version"
)
@ -59,7 +60,7 @@ func kubeDNSAddon(cfg *kubeadmapi.MasterConfiguration, client clientset.Interfac
return err
}
dnsip, err := getDNSIP(client)
dnsip, err := GetDNSIP(cfg.Networking.ServiceSubnet)
if err != nil {
return err
}
@ -148,7 +149,7 @@ func coreDNSAddon(cfg *kubeadmapi.MasterConfiguration, client clientset.Interfac
return fmt.Errorf("error when parsing CoreDNS configMap template: %v", err)
}
dnsip, err := getDNSIP(client)
dnsip, err := GetDNSIP(cfg.Networking.ServiceSubnet)
if err != nil {
return err
}
@ -244,21 +245,20 @@ func createDNSService(dnsService *v1.Service, serviceBytes []byte, client client
return nil
}
// getDNSIP fetches the kubernetes service's ClusterIP and appends a "0" to it in order to get the DNS IP
func getDNSIP(client clientset.Interface) (net.IP, error) {
k8ssvc, err := client.CoreV1().Services(metav1.NamespaceDefault).Get("kubernetes", metav1.GetOptions{})
// GetDNSIP returns a dnsIP, which is 10th IP in svcSubnet CIDR range
func GetDNSIP(svcSubnet string) (net.IP, error) {
// Get the service subnet CIDR
_, svcSubnetCIDR, err := net.ParseCIDR(svcSubnet)
if err != nil {
return nil, fmt.Errorf("couldn't fetch information about the kubernetes service: %v", err)
return nil, fmt.Errorf("couldn't parse service subnet CIDR %q: %v", svcSubnet, err)
}
if len(k8ssvc.Spec.ClusterIP) == 0 {
return nil, fmt.Errorf("couldn't fetch a valid clusterIP from the kubernetes service")
// Selects the 10th IP in service subnet CIDR range as dnsIP
dnsIP, err := ipallocator.GetIndexedIP(svcSubnetCIDR, 10)
if err != nil {
return nil, fmt.Errorf("unable to get tenth IP address from service subnet CIDR %s: %v", svcSubnetCIDR.String(), err)
}
// Build an IP by taking the kubernetes service's clusterIP and appending a "0" and checking that it's valid
dnsIP := net.ParseIP(fmt.Sprintf("%s0", k8ssvc.Spec.ClusterIP))
if dnsIP == nil {
return nil, fmt.Errorf("could not parse dns ip %q: %v", dnsIP, err)
}
return dnsIP, nil
}

30
cmd/kubeadm/app/phases/addons/dns/dns_test.go
View File

@ -144,3 +144,33 @@ func TestCompileManifests(t *testing.T) {
}
}
}
func TestGetDNSIP(t *testing.T) {
var tests = []struct {
svcSubnet, expectedDNSIP string
}{
{
svcSubnet: "10.96.0.0/12",
expectedDNSIP: "10.96.0.10",
},
{
svcSubnet: "10.87.116.64/26",
expectedDNSIP: "10.87.116.74",
},
}
for _, rt := range tests {
dnsIP, err := GetDNSIP(rt.svcSubnet)
if err != nil {
t.Fatalf("couldn't get dnsIP : %v", err)
}
actualDNSIP := dnsIP.String()
if actualDNSIP != rt.expectedDNSIP {
t.Errorf(
"failed GetDNSIP\n\texpected: %s\n\t actual: %s",
rt.expectedDNSIP,
actualDNSIP,
)
}
}
}