TrueCloudLab/coredns
16
0
Fork 2
Code Issues Pull requests 4 Projects Releases Packages Wiki Activity Actions

only create PTR records for endpoints with hostname defined (#6898)

Browse source 
Signed-off-by: Chris O'Haver <cohaver@infoblox.com>
This commit is contained in:
Chris O'Haver 2024-09-30 10:32:13 -04:00 • committed by GitHub
parent b086f081b6
commit f4f0d55dce
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
2 changed files with 21 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
plugin/kubernetes/reverse.go
View file

@ -44,8 +44,13 @@ func (k *Kubernetes) serviceRecordForIP(ip, name string) []msg.Service {
}
for _, eps := range ep.Subsets {
for _, addr := range eps.Addresses {
if addr.IP == ip {
domain := strings.Join([]string{endpointHostname(addr, k.endpointNameMode), ep.Index, Svc, k.primaryZone()}, ".")
// The endpoint's Hostname will be set if this endpoint is supposed to generate a PTR.
// So only return reverse records that match the IP AND have a non-empty hostname.
// Kubernetes more or less keeps this to one canonical service/endpoint per IP, but in the odd event there
// are multiple endpoints for the same IP with hostname set, return them all rather than selecting one
// arbitrarily.
if addr.IP == ip && addr.Hostname != "" {
domain := strings.Join([]string{addr.Hostname, ep.Index, Svc, k.primaryZone()}, ".")
svcs = append(svcs, msg.Service{Host: domain, TTL: k.ttl})
}
}

27
plugin/kubernetes/reverse_test.go
View file

@ -60,8 +60,10 @@ func (APIConnReverseTest) EpIndexReverse(ip string) []*object.Endpoints {
Subsets: []object.EndpointSubset{
{
Addresses: []object.EndpointAddress{
{IP: "10.0.0.100", Hostname: "ep1a"},
{IP: "10.0.0.99", Hostname: "double-ep"}, // this endpoint is used by two services
{IP: "10.0.0.100", Hostname: "ep1a"}, // this endpoint is duplicated across two slices, which can happen in k8s
// 10.0.0.99 is used by two services. Only one will have hostname defined, as is typically enforced by K8s
{IP: "10.0.0.99", Hostname: "double-ep"},
},
Ports: []object.EndpointPort{
{Port: 80, Protocol: "tcp", Name: "http"},
@ -93,7 +95,7 @@ func (APIConnReverseTest) EpIndexReverse(ip string) []*object.Endpoints {
Subsets: []object.EndpointSubset{
{
Addresses: []object.EndpointAddress{
{IP: "10.0.0.100", Hostname: "ep1a"}, // duplicate endpointslice address
{IP: "10.0.0.100", Hostname: "ep1a"}, // This endpoint duplicated across used by two slices, see above
},
Ports: []object.EndpointPort{
{Port: 80, Protocol: "tcp", Name: "http"},
@ -108,7 +110,7 @@ func (APIConnReverseTest) EpIndexReverse(ip string) []*object.Endpoints {
Subsets: []object.EndpointSubset{
{
Addresses: []object.EndpointAddress{
{IP: "10.0.0.99", Hostname: "double-ep"}, // this endpoint is used by two services
{IP: "10.0.0.99", Hostname: ""}, // This endpoint is used by two services, see above
},
Ports: []object.EndpointPort{
{Port: 80, Protocol: "tcp", Name: "http"},
@ -153,6 +155,13 @@ func TestReverse(t *testing.T) {
k.APIConn = &APIConnReverseTest{}
tests := []test.Case{
{
Qname: "99.0.0.10.in-addr.arpa.", Qtype: dns.TypePTR,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.PTR("99.0.0.10.in-addr.arpa. 5 IN PTR double-ep.svc1.testns.svc.cluster.local."),
},
},
{
Qname: "100.0.0.10.in-addr.arpa.", Qtype: dns.TypePTR,
Rcode: dns.RcodeSuccess,
@ -223,14 +232,6 @@ func TestReverse(t *testing.T) {
test.SOA("cluster.local. 5 IN SOA ns.dns.cluster.local. hostmaster.cluster.local. 1502989566 7200 1800 86400 5"),
},
},
{
Qname: "99.0.0.10.in-addr.arpa.", Qtype: dns.TypePTR,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.PTR("99.0.0.10.in-addr.arpa. 5 IN PTR double-ep.svc1.testns.svc.cluster.local."),
test.PTR("99.0.0.10.in-addr.arpa. 5 IN PTR double-ep.svc2.testns.svc.cluster.local."),
},
},
}
ctx := context.TODO()
@ -250,7 +251,7 @@ func TestReverse(t *testing.T) {
t.Fatalf("Test %d: got nil message and no error for: %s %d", i, r.Question[0].Name, r.Question[0].Qtype)
}
if err := test.SortAndCheck(resp, tc); err != nil {
t.Error(err)
t.Errorf("Test %d error: %s", i, err)
}
}
}