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plugin/k8s_external: Resolve headless services (#5505)

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*add option for resolving headless Services without external IPs in k8s_external

Signed-off-by: Tomas Kohout <tomas.kohout1995@gmail.com>
This commit is contained in:
TomasKohout
2022-08-30 20:59:27 +02:00
committed by GitHub
parent b218b56063
commit 6782b7fb42
15 changed files with 491 additions and 81 deletions
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133
plugin/k8s_external/external_test.go
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@@ -21,6 +21,7 @@ func TestExternal(t *testing.T) {
e := New()
e.Zones = []string{"example.com.", "in-addr.arpa."}
e.headless = true
e.Next = test.NextHandler(dns.RcodeSuccess, nil)
e.externalFunc = k.External
e.externalAddrFunc = externalAddress // internal test function
@@ -216,18 +217,86 @@ var tests = []test.Case{
test.SRV("svc12.testns.example.com. 5 IN SRV 0 100 80 dummy.hostname."),
},
},
// headless service
{
Qname: "svc-headless.testns.example.com.", Qtype: dns.TypeA, Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.A("svc-headless.testns.example.com. 5 IN A 1.2.3.4"),
test.A("svc-headless.testns.example.com. 5 IN A 1.2.3.5"),
},
},
{
Qname: "svc-headless.testns.example.com.", Qtype: dns.TypeSRV, Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.SRV("svc-headless.testns.example.com. 5 IN SRV 0 50 80 endpoint-svc-0.svc-headless.testns.example.com."),
test.SRV("svc-headless.testns.example.com. 5 IN SRV 0 50 80 endpoint-svc-1.svc-headless.testns.example.com."),
},
Extra: []dns.RR{
test.A("endpoint-svc-0.svc-headless.testns.example.com. 5 IN A 1.2.3.4"),
test.A("endpoint-svc-1.svc-headless.testns.example.com. 5 IN A 1.2.3.5"),
},
},
{
Qname: "_http._tcp.svc-headless.testns.example.com.", Qtype: dns.TypeSRV, Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.SRV("_http._tcp.svc-headless.testns.example.com. 5 IN SRV 0 50 80 endpoint-svc-0.svc-headless.testns.example.com."),
test.SRV("_http._tcp.svc-headless.testns.example.com. 5 IN SRV 0 50 80 endpoint-svc-1.svc-headless.testns.example.com."),
},
Extra: []dns.RR{
test.A("endpoint-svc-0.svc-headless.testns.example.com. 5 IN A 1.2.3.4"),
test.A("endpoint-svc-1.svc-headless.testns.example.com. 5 IN A 1.2.3.5"),
},
},
{
Qname: "endpoint-svc-0.svc-headless.testns.example.com.", Qtype: dns.TypeSRV, Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.SRV("endpoint-svc-0.svc-headless.testns.example.com. 5 IN SRV 0 100 80 endpoint-svc-0.svc-headless.testns.example.com."),
},
Extra: []dns.RR{
test.A("endpoint-svc-0.svc-headless.testns.example.com. 5 IN A 1.2.3.4"),
},
},
{
Qname: "endpoint-svc-1.svc-headless.testns.example.com.", Qtype: dns.TypeSRV, Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.SRV("endpoint-svc-1.svc-headless.testns.example.com. 5 IN SRV 0 100 80 endpoint-svc-1.svc-headless.testns.example.com."),
},
Extra: []dns.RR{
test.A("endpoint-svc-1.svc-headless.testns.example.com. 5 IN A 1.2.3.5"),
},
},
{
Qname: "endpoint-svc-0.svc-headless.testns.example.com.", Qtype: dns.TypeA, Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.A("endpoint-svc-0.svc-headless.testns.example.com. 5 IN A 1.2.3.4"),
},
},
{
Qname: "endpoint-svc-1.svc-headless.testns.example.com.", Qtype: dns.TypeA, Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.A("endpoint-svc-1.svc-headless.testns.example.com. 5 IN A 1.2.3.5"),
},
},
}
type external struct{}
func (external) HasSynced() bool { return true }
func (external) Run() {}
func (external) Stop() error { return nil }
func (external) EpIndexReverse(string) []*object.Endpoints { return nil }
func (external) SvcIndexReverse(string) []*object.Service { return nil }
func (external) Modified(bool) int64 { return 0 }
func (external) EpIndex(s string) []*object.Endpoints { return nil }
func (external) EndpointsList() []*object.Endpoints { return nil }
func (external) HasSynced() bool { return true }
func (external) Run() {}
func (external) Stop() error { return nil }
func (external) EpIndexReverse(string) []*object.Endpoints { return nil }
func (external) SvcIndexReverse(string) []*object.Service { return nil }
func (external) Modified(bool) int64 { return 0 }
func (external) EpIndex(s string) []*object.Endpoints {
return epIndexExternal[s]
}
func (external) EndpointsList() []*object.Endpoints {
var eps []*object.Endpoints
for _, ep := range epIndexExternal {
eps = append(eps, ep...)
}
return eps
}
func (external) GetNodeByName(ctx context.Context, name string) (*api.Node, error) { return nil, nil }
func (external) SvcIndex(s string) []*object.Service { return svcIndexExternal[s] }
func (external) PodIndex(string) []*object.Pod { return nil }
@@ -252,6 +321,41 @@ func (external) GetNamespaceByName(name string) (*object.Namespace, error) {
}, nil
}
var epIndexExternal = map[string][]*object.Endpoints{
"svc-headless.testns": {
{
Name: "svc-headless",
Namespace: "testns",
Index: "svc-headless.testns",
Subsets: []object.EndpointSubset{
{
Ports: []object.EndpointPort{
{
Port: 80,
Name: "http",
Protocol: "TCP",
},
},
Addresses: []object.EndpointAddress{
{
IP: "1.2.3.4",
Hostname: "endpoint-svc-0",
NodeName: "test-node",
TargetRefName: "endpoint-svc-0",
},
{
IP: "1.2.3.5",
Hostname: "endpoint-svc-1",
NodeName: "test-node",
TargetRefName: "endpoint-svc-1",
},
},
},
},
},
},
}
var svcIndexExternal = map[string][]*object.Service{
"svc1.testns": {
{
@@ -279,6 +383,7 @@ var svcIndexExternal = map[string][]*object.Service{
Namespace: "testns",
Type: api.ServiceTypeLoadBalancer,
ExternalIPs: []string{"2.3.4.5"},
ClusterIPs: []string{"10.0.0.3"},
Ports: []api.ServicePort{{Name: "http", Protocol: "tcp", Port: 80}},
},
},
@@ -287,10 +392,20 @@ var svcIndexExternal = map[string][]*object.Service{
Name: "svc12",
Namespace: "testns",
Type: api.ServiceTypeLoadBalancer,
ClusterIPs: []string{"10.0.0.3"},
ExternalIPs: []string{"dummy.hostname"},
Ports: []api.ServicePort{{Name: "http", Protocol: "tcp", Port: 80}},
},
},
"svc-headless.testns": {
{
Name: "svc-headless",
Namespace: "testns",
Type: api.ServiceTypeClusterIP,
ClusterIPs: []string{"None"},
Ports: []api.ServicePort{{Name: "http", Protocol: "tcp", Port: 80}},
},
},
}
func (external) ServiceList() []*object.Service {
@@ -301,7 +416,7 @@ func (external) ServiceList() []*object.Service {
return svcs
}
func externalAddress(state request.Request) []dns.RR {
func externalAddress(state request.Request, headless bool) []dns.RR {
a := test.A("example.org. IN A 127.0.0.1")
return []dns.RR{a}
}