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mw/kubernetes: add configurable TTL (#995)

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* mw/kubernetes: add configurable TTL

Add ttl option to kubernetes. This defaults to 5s but allows
configuration to go up to 3600.

Configure the tests so that a few actually check for the 5s, while the
rest use the TTL of 303 which is ignored by the checking code.

Fixes #935

* fix tests

* and more
This commit is contained in:
Miek Gieben 2017-08-27 01:32:46 +01:00 • committed by Yong Tang
parent 01f6e8cba5
commit 4049ed4f4b
6 changed files with 90 additions and 27 deletions
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3
middleware/kubernetes/README.md
View file

@ -28,6 +28,7 @@ kubernetes [ZONES...] {
labels EXPRESSION
pods POD-MODE
upstream ADDRESS...
ttl TTL
fallthrough
}
```
@ -62,6 +63,8 @@ kubernetes [ZONES...] {
* `upstream` **ADDRESS [ADDRESS...]** defines the upstream resolvers used for resolving services
that point to external hosts (External Services). **ADDRESS** can be an ip, an ip:port, or a path
to a file structured like resolv.conf.
* `ttl` allows you to set a custom TTL for responses. The default (and allowed minimum) is to use
5 seconds, the maximum is capped at 3600 seconds.
* `fallthrough` If a query for a record in the cluster zone results in NXDOMAIN, normally that is
what the response will be. However, if you specify this option, the query will instead be passed
on down the middleware chain, which can include another middleware to handle the query.

32
middleware/kubernetes/handler_test.go
View file

@ -16,33 +16,33 @@ var dnsTestCases = map[string](test.Case){
Qname: "svc1.testns.svc.cluster.local.", Qtype: dns.TypeA,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.A("svc1.testns.svc.cluster.local. 0 IN A 10.0.0.1"),
test.A("svc1.testns.svc.cluster.local. 5 IN A 10.0.0.1"),
},
},
"A Service (wildcard)": {
Qname: "svc1.*.svc.cluster.local.", Qtype: dns.TypeA,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.A("svc1.*.svc.cluster.local. 0 IN A 10.0.0.1"),
test.A("svc1.*.svc.cluster.local. 5 IN A 10.0.0.1"),
},
},
"SRV Service (wildcard)": {
Qname: "svc1.*.svc.cluster.local.", Qtype: dns.TypeSRV,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{test.SRV("svc1.*.svc.cluster.local. 0 IN SRV 0 100 80 svc1.testns.svc.cluster.local.")},
Extra: []dns.RR{test.A("svc1.testns.svc.cluster.local. 0 IN A 10.0.0.1")},
Answer: []dns.RR{test.SRV("svc1.*.svc.cluster.local. 303 IN SRV 0 100 80 svc1.testns.svc.cluster.local.")},
Extra: []dns.RR{test.A("svc1.testns.svc.cluster.local. 303 IN A 10.0.0.1")},
},
"SRV Service (wildcards)": {
Qname: "*.any.svc1.*.svc.cluster.local.", Qtype: dns.TypeSRV,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{test.SRV("*.any.svc1.*.svc.cluster.local. 0 IN SRV 0 100 80 svc1.testns.svc.cluster.local.")},
Extra: []dns.RR{test.A("svc1.testns.svc.cluster.local. 0 IN A 10.0.0.1")},
Answer: []dns.RR{test.SRV("*.any.svc1.*.svc.cluster.local. 303 IN SRV 0 100 80 svc1.testns.svc.cluster.local.")},
Extra: []dns.RR{test.A("svc1.testns.svc.cluster.local. 303 IN A 10.0.0.1")},
},
"A Service (wildcards)": {
Qname: "*.any.svc1.*.svc.cluster.local.", Qtype: dns.TypeA,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.A("*.any.svc1.*.svc.cluster.local. 0 IN A 10.0.0.1"),
test.A("*.any.svc1.*.svc.cluster.local. 303 IN A 10.0.0.1"),
},
},
"SRV Service Not udp/tcp": {
@ -56,37 +56,37 @@ var dnsTestCases = map[string](test.Case){
Qname: "_http._tcp.svc1.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.SRV("_http._tcp.svc1.testns.svc.cluster.local. 0 IN SRV 0 100 80 svc1.testns.svc.cluster.local."),
test.SRV("_http._tcp.svc1.testns.svc.cluster.local. 303 IN SRV 0 100 80 svc1.testns.svc.cluster.local."),
},
Extra: []dns.RR{
test.A("svc1.testns.svc.cluster.local. 0 IN A 10.0.0.1"),
test.A("svc1.testns.svc.cluster.local. 303 IN A 10.0.0.1"),
},
},
"A Service (Headless)": {
Qname: "hdls1.testns.svc.cluster.local.", Qtype: dns.TypeA,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.A("hdls1.testns.svc.cluster.local. 0 IN A 172.0.0.2"),
test.A("hdls1.testns.svc.cluster.local. 0 IN A 172.0.0.3"),
test.A("hdls1.testns.svc.cluster.local. 303 IN A 172.0.0.2"),
test.A("hdls1.testns.svc.cluster.local. 303 IN A 172.0.0.3"),
},
},
"SRV Service (Headless)": {
Qname: "_http._tcp.hdls1.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.SRV("_http._tcp.hdls1.testns.svc.cluster.local. 0 IN SRV 0 50 80 172-0-0-2.hdls1.testns.svc.cluster.local."),
test.SRV("_http._tcp.hdls1.testns.svc.cluster.local. 0 IN SRV 0 50 80 172-0-0-3.hdls1.testns.svc.cluster.local."),
test.SRV("_http._tcp.hdls1.testns.svc.cluster.local. 303 IN SRV 0 50 80 172-0-0-2.hdls1.testns.svc.cluster.local."),
test.SRV("_http._tcp.hdls1.testns.svc.cluster.local. 303 IN SRV 0 50 80 172-0-0-3.hdls1.testns.svc.cluster.local."),
},
Extra: []dns.RR{
test.A("172-0-0-2.hdls1.testns.svc.cluster.local. 0 IN A 172.0.0.2"),
test.A("172-0-0-3.hdls1.testns.svc.cluster.local. 0 IN A 172.0.0.3"),
test.A("172-0-0-2.hdls1.testns.svc.cluster.local. 303 IN A 172.0.0.2"),
test.A("172-0-0-3.hdls1.testns.svc.cluster.local. 303 IN A 172.0.0.3"),
},
},
"CNAME External": {
Qname: "external.testns.svc.cluster.local.", Qtype: dns.TypeCNAME,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.CNAME("external.testns.svc.cluster.local. 0 IN CNAME ext.interwebs.test."),
test.CNAME("external.testns.svc.cluster.local. 303 IN CNAME ext.interwebs.test."),
},
},
"AAAA Service (existing service)": {

10
middleware/kubernetes/kubernetes.go
View file

@ -40,6 +40,7 @@ type Kubernetes struct {
Namespaces map[string]bool
podMode string
Fallthrough bool
ttl uint32
primaryZoneIndex int
interfaceAddrsFunc func() net.IP
@ -55,6 +56,7 @@ func New(zones []string) *Kubernetes {
k.interfaceAddrsFunc = func() net.IP { return net.ParseIP("127.0.0.1") }
k.podMode = podModeDisabled
k.Proxy = proxy.Proxy{}
k.ttl = defaultTTL
return k
}
@ -382,7 +384,7 @@ func (k *Kubernetes) findServices(r recordRequest, zone string) (services []msg.
if !(match(r.port, p.Name) && match(r.protocol, string(p.Protocol))) {
continue
}
s := msg.Service{Host: addr.IP, Port: int(p.Port)}
s := msg.Service{Host: addr.IP, Port: int(p.Port), TTL: k.ttl}
s.Key = strings.Join([]string{zonePath, Svc, svc.Namespace, svc.Name, endpointHostname(addr)}, "/")
err = nil
@ -397,7 +399,7 @@ func (k *Kubernetes) findServices(r recordRequest, zone string) (services []msg.
// External service
if svc.Spec.ExternalName != "" {
s := msg.Service{Key: strings.Join([]string{zonePath, Svc, svc.Namespace, svc.Name}, "/"), Host: svc.Spec.ExternalName}
s := msg.Service{Key: strings.Join([]string{zonePath, Svc, svc.Namespace, svc.Name}, "/"), Host: svc.Spec.ExternalName, TTL: k.ttl}
if t, _ := s.HostType(); t == dns.TypeCNAME {
s.Key = strings.Join([]string{zonePath, Svc, svc.Namespace, svc.Name}, "/")
services = append(services, s)
@ -416,7 +418,7 @@ func (k *Kubernetes) findServices(r recordRequest, zone string) (services []msg.
err = nil
s := msg.Service{Host: svc.Spec.ClusterIP, Port: int(p.Port)}
s := msg.Service{Host: svc.Spec.ClusterIP, Port: int(p.Port), TTL: k.ttl}
s.Key = strings.Join([]string{zonePath, Svc, svc.Namespace, svc.Name}, "/")
services = append(services, s)
@ -455,4 +457,6 @@ const (
Svc = "svc"
// Pod is the DNS schema for kubernetes pods
Pod = "pod"
// defaultTTL to apply to all answers.
defaultTTL = 5
)

14
middleware/kubernetes/setup.go
View file

@ -3,6 +3,7 @@ package kubernetes
import (
"errors"
"fmt"
"strconv"
"strings"
"time"
@ -174,6 +175,19 @@ func kubernetesParse(c *caddy.Controller) (*Kubernetes, dnsControlOpts, error) {
return nil, opts, err
}
k8s.Proxy = proxy.NewLookup(ups)
case "ttl":
args := c.RemainingArgs()
if len(args) == 0 {
return nil, opts, c.ArgErr()
}
t, err := strconv.Atoi(args[0])
if err != nil {
return nil, opts, err
}
if t < 5 || t > 3600 {
return nil, opts, c.Errf("ttl must be in range [5, 3600]: %d", t)
}
k8s.ttl = uint32(t)
default:
return nil, opts, c.Errf("unknown property '%s'", c.Val())
}

45
middleware/kubernetes/setup_ttl_test.go Normal file
View file

@ -0,0 +1,45 @@
package kubernetes
import (
"testing"
"github.com/mholt/caddy"
)
func TestKubernetesParseTTL(t *testing.T) {
tests := []struct {
input string // Corefile data as string
expectedTTL uint32 // expected count of defined zones.
shouldErr bool
}{
{`kubernetes cluster.local {
ttl 56
}`, 56, false},
{`kubernetes cluster.local`, defaultTTL, false},
{`kubernetes cluster.local {
ttl -1
}`, 0, true},
{`kubernetes cluster.local {
ttl 3601
}`, 0, true},
}
for i, tc := range tests {
c := caddy.NewTestController("dns", tc.input)
k, _, err := kubernetesParse(c)
if err != nil && !tc.shouldErr {
t.Fatalf("Test %d: Expected no error, got %q", i, err)
}
if err == nil && tc.shouldErr {
t.Fatalf("Test %d: Expected error, got none", i)
}
if err != nil && tc.shouldErr {
// input should error
continue
}
if k.ttl != tc.expectedTTL {
t.Errorf("Test %d: Expected TTl to be %d, got %d", i, tc.expectedTTL, k.ttl)
}
}
}

13
test/kubernetes_test.go
View file

@ -30,7 +30,7 @@ var dnsTestCases = []test.Case{
Qname: "svc-1-a.test-1.svc.cluster.local.", Qtype: dns.TypeA,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.A("svc-1-a.test-1.svc.cluster.local. 303 IN A 10.0.0.100"),
test.A("svc-1-a.test-1.svc.cluster.local. 5 IN A 10.0.0.100"),
},
},
{
@ -535,9 +535,7 @@ var dnsTestCasesFallthrough = []test.Case{
Rcode: dns.RcodeSuccess,
Answer: append(srvResponse("_c-port._UDP.*.test-1.svc.cluster.local.", "TypeSRV", "headless-svc", "test-1"),
[]dns.RR{
test.SRV("_c-port._UDP.*.test-1.svc.cluster.local. 303 IN SRV 0 33 1234 svc-c.test-1.svc.cluster.local."),
}...),
test.SRV("_c-port._UDP.*.test-1.svc.cluster.local. 303 IN SRV 0 33 1234 svc-c.test-1.svc.cluster.local.")}...),
Extra: append(srvResponse("_c-port._UDP.*.test-1.svc.cluster.local.", "TypeA", "headless-svc", "test-1"),
[]dns.RR{
test.A("svc-c.test-1.svc.cluster.local. 303 IN A 10.0.0.115"),
@ -626,14 +624,14 @@ var dnsTestCasesFallthrough = []test.Case{
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.A("example.net. 303 IN A 13.14.15.16"),
test.CNAME("ext-svc.test-1.svc.cluster.local. 0 IN CNAME example.net."),
test.CNAME("ext-svc.test-1.svc.cluster.local. 303 IN CNAME example.net."),
},
},
{
Qname: "ext-svc.test-1.svc.cluster.local.", Qtype: dns.TypeCNAME,
Rcode: dns.RcodeSuccess,
Answer: []dns.RR{
test.CNAME("ext-svc.test-1.svc.cluster.local. 0 IN CNAME example.net."),
test.CNAME("ext-svc.test-1.svc.cluster.local. 303 IN CNAME example.net."),
},
},
{
@ -855,7 +853,7 @@ func srvResponse(qname, responsetype, namespace, name string) []dns.RR {
ip := strings.Replace(result[i], ".", "-", -1)
t := strconv.Itoa(100 / (lr + 1))
if responsetype == "TypeA" {
rr = append(rr, test.A(ip+"."+namespace+"."+name+".svc.cluster.local. 0 IN A "+result[i]))
rr = append(rr, test.A(ip+"."+namespace+"."+name+".svc.cluster.local. 303 IN A "+result[i]))
}
if responsetype == "TypeSRV" && namespace == "headless-svc" {
rr = append(rr, test.SRV(qname+" 303 IN SRV 0 "+t+" 1234 "+ip+"."+namespace+"."+name+".svc.cluster.local."))
@ -864,7 +862,6 @@ func srvResponse(qname, responsetype, namespace, name string) []dns.RR {
rr = append(rr, test.SRV(qname+" 303 IN SRV 0 "+t+" 443 "+ip+"."+namespace+"."+name+".svc.cluster.local."))
rr = append(rr, test.SRV(qname+" 303 IN SRV 0 "+t+" 80 "+ip+"."+namespace+"."+name+".svc.cluster.local."))
}
}
return rr
}