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Add k8s external service CNAMEs (#677)

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* Add external service cnames

* remove cruft

* update CI k8s version

* change CI k8s version

* min k8s ver for ext services

* trying k8s 1.5

* k8s 1.5 requires ports spec

* remove kruft

* update dns schema version
This commit is contained in:
Chris O'Haver 2017-05-30 08:20:39 -04:00 • committed by Miek Gieben
parent 2f2c90f391
commit d917ff5ac2
11 changed files with 293 additions and 16 deletions
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35
middleware/kubernetes/kubernetes.go
View file

@ -55,7 +55,7 @@ const (
// PodModeInsecure is where pod requests are answered without verfying they exist
PodModeInsecure = "insecure"
// DNSSchemaVersion is the schema version: https://github.com/kubernetes/dns/blob/master/docs/specification.md
DNSSchemaVersion = "1.0.0"
DNSSchemaVersion = "1.0.1"
)
type endpoint struct {
@ -97,7 +97,7 @@ func (k *Kubernetes) Services(state request.Request, exact bool, opt middleware.
}
switch state.Type() {
case "A", "SRV":
case "A", "CNAME":
if state.Type() == "A" && isDefaultNS(state.Name(), r) {
// If this is an A request for "ns.dns", respond with a "fake" record for coredns.
// SOA records always use this hardcoded name
@ -106,6 +106,16 @@ func (k *Kubernetes) Services(state request.Request, exact bool, opt middleware.
}
s, e := k.Records(r)
return s, nil, e // Haven't implemented debug queries yet.
case "SRV":
s, e := k.Records(r)
// SRV for external services is not yet implemented, so remove those records
noext := []msg.Service{}
for _, svc := range s {
if t, _ := svc.HostType(); t != dns.TypeCNAME {
noext = append(noext, svc)
}
}
return noext, nil, e
case "TXT":
err := k.recordsForTXT(r, &svcs)
return svcs, nil, err
@ -373,6 +383,14 @@ func (k *Kubernetes) getRecordsForK8sItems(services []service, pods []pod, zone
Port: int(p.Port)}
records = append(records, s)
}
// If the addr is not an IP (i.e. an external service), add the record ...
s := msg.Service{
Key: strings.Join([]string{zonePath, "svc", svc.namespace, svc.name}, "/"),
Host: svc.addr}
if t, _ := s.HostType(); t == dns.TypeCNAME {
records = append(records, s)
}
}
}
@ -466,8 +484,16 @@ func (k *Kubernetes) findServices(r recordRequest) ([]service, error) {
if nsWildcard && (len(k.Namespaces) > 0) && (!dnsstrings.StringInSlice(svc.Namespace, k.Namespaces)) {
continue
}
s := service{name: svc.Name, namespace: svc.Namespace, addr: svc.Spec.ClusterIP}
if s.addr != api.ClusterIPNone {
s := service{name: svc.Name, namespace: svc.Namespace}
// External Service
if svc.Spec.ExternalName != "" {
s.addr = svc.Spec.ExternalName
resultItems = append(resultItems, s)
continue
}
// ClusterIP service
if svc.Spec.ClusterIP != api.ClusterIPNone {
s.addr = svc.Spec.ClusterIP
for _, p := range svc.Spec.Ports {
if !(symbolMatches(r.port, strings.ToLower(p.Name), portWildcard) && symbolMatches(r.protocol, strings.ToLower(string(p.Protocol)), protocolWildcard)) {
continue
@ -478,6 +504,7 @@ func (k *Kubernetes) findServices(r recordRequest) ([]service, error) {
continue
}
// Headless service
s.addr = svc.Spec.ClusterIP
endpointsList := k.APIConn.EndpointsList()
for _, ep := range endpointsList.Items {